This class provides access to the system search services.
In practice, you won't interact with this class directly, as search
services are provided through methods in {@link android.app.Activity Activity}
methods and the the {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
{@link android.content.Intent Intent}. This class does provide a basic
overview of search services and how to integrate them with your activities.
If you do require direct access to the Search Manager, do not instantiate
this class directly; instead, retrieve it through
{@link android.content.Context#getSystemService
context.getSystemService(Context.SEARCH_SERVICE)}.
Topics covered here:
- Developer Guide
- How Search Is Invoked
- Query-Search Applications
- Filter-Search Applications
- Search Suggestions
- Action Keys
- Searchability Metadata
- Passing Search Context
- Protecting User Privacy
Developer Guide
The ability to search for user, system, or network based data is considered to be
a core user-level feature of the android platform. At any time, the user should be
able to use a familiar command, button, or keystroke to invoke search, and the user
should be able to search any data which is available to them. The goal is to make search
appear to the user as a seamless, system-wide feature.
In terms of implementation, there are three broad classes of Applications:
- Applications that are not inherently searchable
- Query-Search Applications
- Filter-Search Applications
These categories, as well as related topics, are discussed in
the sections below.
Even if your application is not searchable, it can still support the invocation of
search. Please review the section How Search Is Invoked
for more information on how to support this.
Many applications are searchable. These are
the applications which can convert a query string into a list of results.
Within this subset, applications can be grouped loosely into two families:
- Query Search applications perform batch-mode searches - each query string is
converted to a list of results.
- Filter Search applications provide live filter-as-you-type searches.
Generally speaking, you would use query search for network-based data, and filter
search for local data, but this is not a hard requirement and applications
are free to use the model that fits them best (or invent a new model).
It should be clear that the search implementation decouples "search
invocation" from "searchable". This satisfies the goal of making search appear
to be "universal". The user should be able to launch any search from
almost any context.
How Search Is Invoked
Unless impossible or inapplicable, all applications should support
invoking the search UI. This means that when the user invokes the search command,
a search UI will be presented to them. The search command is currently defined as a menu
item called "Search" (with an alphabetic shortcut key of "S"), or on some devices, a dedicated
search button key.
If your application is not inherently searchable, you can also allow the search UI
to be invoked in a "web search" mode. If the user enters a search term and clicks the
"Search" button, this will bring the browser to the front and will launch a web-based
search. The user will be able to click the "Back" button and return to your application.
In general this is implemented by your activity, or the {@link android.app.Activity Activity}
base class, which captures the search command and invokes the Search Manager to
display and operate the search UI. You can also cause the search UI to be presented in response
to user keystrokes in your activity (for example, to instantly start filter searching while
viewing a list and typing any key).
The search UI is presented as a floating
window and does not cause any change in the activity stack. If the user
cancels search, the previous activity re-emerges. If the user launches a
search, this will be done by sending a search {@link android.content.Intent Intent} (see below),
and the normal intent-handling sequence will take place (your activity will pause,
etc.)
What you need to do: First, you should consider the way in which you want to
handle invoking search. There are four broad (and partially overlapping) categories for
you to choose from.
- You can capture the search command yourself, by including a search
button or menu item - and invoking the search UI directly.
- You can provide a type-to-search feature, in which search is invoked automatically
when the user enters any characters.
- Even if your application is not inherently searchable, you can allow web search,
via the search key (or even via a search menu item).
- You can disable search entirely. This should only be used in very rare circumstances,
as search is a system-wide feature and users will expect it to be available in all contexts.
How to define a search menu. The system provides the following resources which may
be useful when adding a search item to your menu:
- android.R.drawable.ic_search_category_default is an icon you can use in your menu.
- {@link #MENU_KEY SearchManager.MENU_KEY} is the recommended alphabetic shortcut.
How to invoke search directly. In order to invoke search directly, from a button
or menu item, you can launch a generic search by calling
{@link android.app.Activity#onSearchRequested onSearchRequested} as shown:
onSearchRequested();
How to implement type-to-search. While setting up your activity, call
{@link android.app.Activity#setDefaultKeyMode setDefaultKeyMode}:
setDefaultKeyMode(DEFAULT_KEYS_SEARCH_LOCAL); // search within your activity
setDefaultKeyMode(DEFAULT_KEYS_SEARCH_GLOBAL); // search using platform global search
How to enable web-based search. In addition to searching within your activity or
application, you can also use the Search Manager to invoke a platform-global search, typically
a web search. There are two ways to do this:
- You can simply define "search" within your application or activity to mean global search.
This is described in more detail in the
Searchability Metadata section. Briefly, you will
add a single meta-data entry to your manifest, declaring that the default search
for your application is "*". This indicates to the system that no application-specific
search activity is provided, and that it should launch web-based search instead.
- You can specify this at invocation time via default keys (see above), overriding
{@link android.app.Activity#onSearchRequested}, or via a direct call to
{@link android.app.Activity#startSearch}. This is most useful if you wish to provide local
searchability and access to global search.
How to disable search from your activity. search is a system-wide feature and users
will expect it to be available in all contexts. If your UI design absolutely precludes
launching search, override {@link android.app.Activity#onSearchRequested onSearchRequested}
as shown:
@Override
public boolean onSearchRequested() {
return false;
}
Managing focus and knowing if Search is active. The search UI is not a separate
activity, and when the UI is invoked or dismissed, your activity will not typically be paused,
resumed, or otherwise notified by the methods defined in
Application Fundamentals:
Activity Lifecycle. The search UI is
handled in the same way as other system UI elements which may appear from time to time, such as
notifications, screen locks, or other system alerts:
When the search UI appears, your activity will lose input focus.
When the search activity is dismissed, there are three possible outcomes:
- If the user simply canceled the search UI, your activity will regain input focus and
proceed as before. See {@link #setOnDismissListener} and {@link #setOnCancelListener} if you
required direct notification of search dialog dismissals.
- If the user launched a search, and this required switching to another activity to receive
and process the search {@link android.content.Intent Intent}, your activity will receive the
normal sequence of activity pause or stop notifications.
- If the user launched a search, and the current activity is the recipient of the search
{@link android.content.Intent Intent}, you will receive notification via the
{@link android.app.Activity#onNewIntent onNewIntent()} method.
This list is provided in order to clarify the ways in which your activities will interact with
the search UI. More details on searchable activities and search intents are provided in the
sections below.
Query-Search Applications
Query-search applications are those that take a single query (e.g. a search
string) and present a set of results that may fit. Primary examples include
web queries, map lookups, or email searches (with the common thread being
network query dispatch). It may also be the case that certain local searches
are treated this way. It's up to the application to decide.
What you need to do: The following steps are necessary in order to
implement query search.
- Implement search invocation as described above. (Strictly speaking,
these are decoupled, but it would make little sense to be "searchable" but not
"search-invoking".)
- Your application should have an activity that takes a search string and
converts it to a list of results. This could be your primary display activity
or it could be a dedicated search results activity. This is your searchable
activity and every query-search application must have one.
- In the searchable activity, in onCreate(), you must receive and handle the
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
{@link android.content.Intent Intent}. The text to search (query string) for is provided by
calling
{@link #QUERY getStringExtra(SearchManager.QUERY)}.
- To identify and support your searchable activity, you'll need to
provide an XML file providing searchability configuration parameters, a reference to that
in your searchable activity's manifest
entry, and an intent-filter declaring that you can
receive ACTION_SEARCH intents. This is described in more detail in the
Searchability Metadata section.
- Your manifest also needs a metadata entry
providing a global reference to the searchable activity. This is the "glue" directing the search
UI, when invoked from any of your other activities, to use your application as the
default search context. This is also described in more detail in the
Searchability Metadata section.
- Finally, you may want to define your search results activity as with the
{@link android.R.attr#launchMode singleTop} launchMode flag. This allows the system
to launch searches from/to the same activity without creating a pile of them on the
activity stack. If you do this, be sure to also override
{@link android.app.Activity#onNewIntent onNewIntent} to handle the
updated intents (with new queries) as they arrive.
Code snippet showing handling of intents in your search activity:
@Override
protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
final Intent queryIntent = getIntent();
final String queryAction = queryIntent.getAction();
if (Intent.ACTION_SEARCH.equals(queryAction)) {
doSearchWithIntent(queryIntent);
}
}
private void doSearchWithIntent(final Intent queryIntent) {
final String queryString = queryIntent.getStringExtra(SearchManager.QUERY);
doSearchWithQuery(queryString);
}
Filter-Search Applications
Filter-search applications are those that use live text entry (e.g. keystrokes)) to
display and continuously update a list of results. Primary examples include applications
that use locally-stored data.
Filter search is not directly supported by the Search Manager. Most filter search
implementations will use variants of {@link android.widget.Filterable}, such as a
{@link android.widget.ListView} bound to a {@link android.widget.SimpleCursorAdapter}. However,
you may find it useful to mix them together, by declaring your filtered view searchable. With
this configuration, you can still present the standard search dialog in all activities
within your application, but transition to a filtered search when you enter the activity
and display the results.
Search Suggestions
A powerful feature of the Search Manager is the ability of any application to easily provide
live "suggestions" in order to prompt the user. Each application implements suggestions in a
different, unique, and appropriate way. Suggestions be drawn from many sources, including but
not limited to:
- Actual searchable results (e.g. names in the address book)
- Recently entered queries
- Recently viewed data or results
- Contextually appropriate queries or results
- Summaries of possible results
Another feature of suggestions is that they can expose queries or results before the user
ever visits the application. This reduces the amount of context switching required, and helps
the user access their data quickly and with less context shifting. In order to provide this
capability, suggestions are accessed via a
{@link android.content.ContentProvider Content Provider}.
The primary form of suggestions is known as queried suggestions and is based on query
text that the user has already typed. This would generally be based on partial matches in
the available data. In certain situations - for example, when no query text has been typed yet -
an application may also opt to provide zero-query suggestions.
These would typically be drawn from the same data source, but because no partial query text is
available, they should be weighted based on other factors - for example, most recent queries
or most recent results.
Overview of how suggestions are provided. When the search manager identifies a
particular activity as searchable, it will check for certain metadata which indicates that
there is also a source of suggestions. If suggestions are provided, the following steps are
taken.
- Using formatting information found in the metadata, the user's query text (whatever
has been typed so far) will be formatted into a query and sent to the suggestions
{@link android.content.ContentProvider Content Provider}.
- The suggestions {@link android.content.ContentProvider Content Provider} will create a
{@link android.database.Cursor Cursor} which can iterate over the possible suggestions.
- The search manager will populate a list using display data found in each row of the cursor,
and display these suggestions to the user.
- If the user types another key, or changes the query in any way, the above steps are repeated
and the suggestions list is updated or repopulated.
- If the user clicks or touches the "GO" button, the suggestions are ignored and the search is
launched using the normal {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} type of
{@link android.content.Intent Intent}.
- If the user uses the directional controls to navigate the focus into the suggestions list,
the query text will be updated while the user navigates from suggestion to suggestion. The user
can then click or touch the updated query and edit it further. If the user navigates back to
the edit field, the original typed query is restored.
- If the user clicks or touches a particular suggestion, then a combination of data from the
cursor and
values found in the metadata are used to synthesize an Intent and send it to the application.
Depending on the design of the activity and the way it implements search, this might be a
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} (in order to launch a query), or it
might be a {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}, in order to proceed directly
to display of specific data.
Simple Recent-Query-Based Suggestions. The Android framework provides a simple Search
Suggestions provider, which simply records and replays recent queries. For many applications,
this will be sufficient. The basic steps you will need to
do, in order to use the built-in recent queries suggestions provider, are as follows:
- Implement and test query search, as described in the previous sections.
- Create a Provider within your application by extending
{@link android.content.SearchRecentSuggestionsProvider}.
- Create a manifest entry describing your provider.
- Update your searchable activity's XML configuration file with information about your
provider.
- In your searchable activities, capture any user-generated queries and record them
for future searches by calling {@link android.provider.SearchRecentSuggestions#saveRecentQuery}.
For complete implementation details, please refer to
{@link android.content.SearchRecentSuggestionsProvider}. The rest of the information in this
section should not be necessary, as it refers to custom suggestions providers.
Creating a Customized Suggestions Provider: In order to create more sophisticated
suggestion providers, you'll need to take the following steps:
- Implement and test query search, as described in the previous sections.
- Decide how you wish to receive suggestions. Just like queries that the user enters,
suggestions will be delivered to your searchable activity as
{@link android.content.Intent Intent} messages; Unlike simple queries, you have quite a bit of
flexibility in forming those intents. A query search application will probably
wish to continue receiving the {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
{@link android.content.Intent Intent}, which will launch a query search using query text as
provided by the suggestion. A filter search application will probably wish to
receive the {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}
{@link android.content.Intent Intent}, which will take the user directly to a selected entry.
Other interesting suggestions, including hybrids, are possible, and the suggestion provider
can easily mix-and-match results to provide a richer set of suggestions for the user. Finally,
you'll need to update your searchable activity (or other activities) to receive the intents
as you've defined them.
- Implement a Content Provider that provides suggestions. If you already have one, and it
has access to your suggestions data. If not, you'll have to create one.
You'll also provide information about your Content Provider in your
package's manifest.
- Update your searchable activity's XML configuration file. There are two categories of
information used for suggestions:
- The first is (required) data that the search manager will
use to format the queries which are sent to the Content Provider.
- The second is (optional) parameters to configure structure
if intents generated by suggestions.
Configuring your Content Provider to Receive Suggestion Queries. The basic job of
a search suggestions {@link android.content.ContentProvider Content Provider} is to provide
"live" (while-you-type) conversion of the user's query text into a set of zero or more
suggestions. Each application is free to define the conversion, and as described above there are
many possible solutions. This section simply defines how to communicate with the suggestion
provider.
The Search Manager must first determine if your package provides suggestions. This is done
by examination of your searchable meta-data XML file. The android:searchSuggestAuthority
attribute, if provided, is the signal to obtain & display suggestions.
Every query includes a Uri, and the Search Manager will format the Uri as shown:
content:// your.suggest.authority / your.suggest.path / SearchManager.SUGGEST_URI_PATH_QUERY
Your Content Provider can receive the query text in one of two ways.
- Query provided as a selection argument. If you define the attribute value
android:searchSuggestSelection and include a string, this string will be passed as the
selection parameter to your Content Provider's query function. You must define a single
selection argument, using the '?' character. The user's query text will be passed to you
as the first element of the selection arguments array.
- Query provided with Data Uri. If you do not define the attribute value
android:searchSuggestSelection, then the Search Manager will append another "/" followed by
the user's query to the query Uri. The query will be encoding using Uri encoding rules - don't
forget to decode it. (See {@link android.net.Uri#getPathSegments} and
{@link android.net.Uri#getLastPathSegment} for helpful utilities you can use here.)
Handling empty queries. Your application should handle the "empty query"
(no user text entered) case properly, and generate useful suggestions in this case. There are a
number of ways to do this; Two are outlined here:
- For a simple filter search of local data, you could simply present the entire dataset,
unfiltered. (example: People)
- For a query search, you could simply present the most recent queries. This allows the user
to quickly repeat a recent search.
The Format of Individual Suggestions. Your suggestions are communicated back to the
Search Manager by way of a {@link android.database.Cursor Cursor}. The Search Manager will
usually pass a null Projection, which means that your provider can simply return all appropriate
columns for each suggestion. The columns currently defined are:
Column Name | Description | Required? |
{@link #SUGGEST_COLUMN_FORMAT} |
Unused - can be null. |
No |
{@link #SUGGEST_COLUMN_TEXT_1} |
This is the line of text that will be presented to the user as the suggestion. |
Yes |
{@link #SUGGEST_COLUMN_TEXT_2} |
If your cursor includes this column, then all suggestions will be provided in a
two-line format. The data in this column will be displayed as a second, smaller
line of text below the primary suggestion, or it can be null or empty to indicate no
text in this row's suggestion. |
No |
{@link #SUGGEST_COLUMN_ICON_1} |
If your cursor includes this column, then all suggestions will be provided in an
icons+text format. This value should be a reference (resource ID) of the icon to
draw on the left side, or it can be null or zero to indicate no icon in this row.
You must provide both cursor columns, or neither.
|
No, but required if you also have {@link #SUGGEST_COLUMN_ICON_2} |
{@link #SUGGEST_COLUMN_ICON_2} |
If your cursor includes this column, then all suggestions will be provided in an
icons+text format. This value should be a reference (resource ID) of the icon to
draw on the right side, or it can be null or zero to indicate no icon in this row.
You must provide both cursor columns, or neither.
|
No, but required if you also have {@link #SUGGEST_COLUMN_ICON_1} |
{@link #SUGGEST_COLUMN_INTENT_ACTION} |
If this column exists and this element exists at the given row, this is the
action that will be used when forming the suggestion's intent. If the element is
not provided, the action will be taken from the android:searchSuggestIntentAction
field in your XML metadata. At least one of these must be present for the
suggestion to generate an intent. Note: If your action is the same for all
suggestions, it is more efficient to specify it using XML metadata and omit it from
the cursor. |
No |
{@link #SUGGEST_COLUMN_INTENT_DATA} |
If this column exists and this element exists at the given row, this is the
data that will be used when forming the suggestion's intent. If the element is not
provided, the data will be taken from the android:searchSuggestIntentData field in
your XML metadata. If neither source is provided, the Intent's data field will be
null. Note: If your data is the same for all suggestions, or can be described
using a constant part and a specific ID, it is more efficient to specify it using
XML metadata and omit it from the cursor. |
No |
{@link #SUGGEST_COLUMN_INTENT_DATA_ID} |
If this column exists and this element exists at the given row, then "/" and
this value will be appended to the data field in the Intent. This should only be
used if the data field has already been set to an appropriate base string. |
No |
{@link #SUGGEST_COLUMN_QUERY} |
If this column exists and this element exists at the given row, this is the
data that will be used when forming the suggestion's query. |
Required if suggestion's action is
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}, optional otherwise. |
Other Columns |
Finally, if you have defined any Action Keys and you wish
for them to have suggestion-specific definitions, you'll need to define one
additional column per action key. The action key will only trigger if the
currently-selection suggestion has a non-empty string in the corresponding column.
See the section on Action Keys for additional details and
implementation steps. |
No |
Clearly there are quite a few permutations of your suggestion data, but in the next section
we'll look at a few simple combinations that you'll select from.
The Format Of Intents Sent By Search Suggestions. Although there are many ways to
configure these intents, this document will provide specific information on just a few of them.
- Launch a query. In this model, each suggestion represents a query that your
searchable activity can perform, and the {@link android.content.Intent Intent} will be formatted
exactly like those sent when the user enters query text and clicks the "GO" button:
- Action: {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} provided
using your XML metadata (android:searchSuggestIntentAction).
- Data: empty (not used).
- Query: query text supplied by the cursor.
- Go directly to a result, using a complete Data Uri. In this model, the user will be
taken directly to a specific result.
- Action: {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}
- Data: a complete Uri, supplied by the cursor, that identifies the desired data.
- Query: query text supplied with the suggestion (probably ignored)
- Go directly to a result, using a synthesized Data Uri. This has the same result
as the previous suggestion, but provides the Data Uri in a different way.
- Action: {@link android.content.Intent#ACTION_VIEW ACTION_VIEW}
- Data: The search manager will assemble a Data Uri using the following elements:
a Uri fragment provided in your XML metadata (android:searchSuggestIntentData), followed by
a single "/", followed by the value found in the {@link #SUGGEST_COLUMN_INTENT_DATA_ID}
entry in your cursor.
- Query: query text supplied with the suggestion (probably ignored)
This list is not meant to be exhaustive. Applications should feel free to define other types
of suggestions. For example, you could reduce long lists of results to summaries, and use one
of the above intents (or one of your own) with specially formatted Data Uri's to display more
detailed results. Or you could display textual shortcuts as suggestions, but launch a display
in a more data-appropriate format such as media artwork.
Suggestion Rewriting. If the user navigates through the suggestions list, the UI
may temporarily rewrite the user's query with a query that matches the currently selected
suggestion. This enables the user to see what query is being suggested, and also allows the user
to click or touch in the entry EditText element and make further edits to the query before
dispatching it. In order to perform this correctly, the Search UI needs to know exactly what
text to rewrite the query with.
For each suggestion, the following logic is used to select a new query string:
- If the suggestion provides an explicit value in the {@link #SUGGEST_COLUMN_QUERY}
column, this value will be used.
- If the metadata includes the queryRewriteFromData flag, and the suggestion provides an
explicit value for the intent Data field, this Uri will be used. Note that this should only be
used with Uri's that are intended to be user-visible, such as HTTP. Internal Uri schemes should
not be used in this way.
- If the metadata includes the queryRewriteFromText flag, the text in
{@link #SUGGEST_COLUMN_TEXT_1} will be used. This should be used for suggestions in which no
query text is provided and the SUGGEST_COLUMN_INTENT_DATA values are not suitable for user
inspection and editing.
Action Keys
Searchable activities may also wish to provide shortcuts based on the various action keys
available on the device. The most basic example of this is the contacts app, which enables the
green "dial" key for quick access during searching. Not all action keys are available on
every device, and not all are allowed to be overriden in this way. (For example, the "Home"
key must always return to the home screen, with no exceptions.)
In order to define action keys for your searchable application, you must do two things.
- You'll add one or more actionkey elements to your searchable metadata configuration
file. Each element defines one of the keycodes you are interested in,
defines the conditions under which they are sent, and provides details
on how to communicate the action key event back to your searchable activity.
- In your broadcast receiver, if you wish, you can check for action keys by checking the
extras field of the {@link android.content.Intent Intent}.
Updating metadata. For each keycode of interest, you must add an <actionkey>
element. Within this element you must define two or three attributes. The first attribute,
<android:keycode>, is required; It is the key code of the action key event, as defined in
{@link android.view.KeyEvent}. The remaining two attributes define the value of the actionkey's
message, which will be passed to your searchable activity in the
{@link android.content.Intent Intent} (see below for more details). Although each of these
attributes is optional, you must define one or both for the action key to have any effect.
<android:queryActionMsg> provides the message that will be sent if the action key is
pressed while the user is simply entering query text. <android:suggestActionMsgColumn>
is used when action keys are tied to specific suggestions. This attribute provides the name
of a column in your suggestion cursor; The individual suggestion, in that column,
provides the message. (If the cell is empty or null, that suggestion will not work with that
action key.)
See the Searchability Metadata section for more details
and examples.
Receiving Action Keys Intents launched by action keys will be specially marked
using a combination of values. This enables your searchable application to examine the intent,
if necessary, and perform special processing. For example, clicking a suggested contact might
simply display them; Selecting a suggested contact and clicking the dial button might
immediately call them.
When a search {@link android.content.Intent Intent} is launched by an action key, two values
will be added to the extras field.
- To examine the key code, use {@link android.content.Intent#getIntExtra
getIntExtra(SearchManager.ACTION_KEY)}.
- To examine the message string, use {@link android.content.Intent#getStringExtra
getStringExtra(SearchManager.ACTION_MSG)}
Searchability Metadata
Every activity that is searchable must provide a small amount of additional information
in order to properly configure the search system. This controls the way that your search
is presented to the user, and controls for the various modalities described previously.
If your application is not searchable,
then you do not need to provide any search metadata, and you can skip the rest of this section.
When this search metadata cannot be found, the search manager will assume that the activity
does not implement search. (Note: to implement web-based search, you will need to add
the android.app.default_searchable metadata to your manifest, as shown below.)
Values you supply in metadata apply only to each local searchable activity. Each
searchable activity can define a completely unique search experience relevant to its own
capabilities and user experience requirements, and a single application can even define multiple
searchable activities.
Metadata for searchable activity. As with your search implementations described
above, you must first identify which of your activities is searchable. In the
manifest entry for this activity, you must
provide two elements:
- An intent-filter specifying that you can receive and process the
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} {@link android.content.Intent Intent}.
- A reference to a small XML file (typically called "searchable.xml") which contains the
remaining configuration information for how your application implements search.
Here is a snippet showing the necessary elements in the
manifest entry for your searchable activity.
<!-- Search Activity - searchable -->
<activity android:name="MySearchActivity"
android:label="Search"
android:launchMode="singleTop">
<intent-filter>
<action android:name="android.intent.action.SEARCH" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
<meta-data android:name="android.app.searchable"
android:resource="@xml/searchable" />
</activity>
Next, you must provide the rest of the searchability configuration in
the small XML file, stored in the ../xml/ folder in your build. The XML file is a
simple enumeration of the search configuration parameters for searching within this activity,
application, or package. Here is a sample XML file (named searchable.xml, for use with
the above manifest) for a query-search activity.
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
android:label="@string/search_label"
android:hint="@string/search_hint" >
</searchable>
Note that all user-visible strings must be provided in the form of "@string"
references. Hard-coded strings, which cannot be localized, will not work properly in search
metadata.
Attributes you can set in search metadata:
Attribute | Description | Required? |
android:label |
This is the name for your application that will be presented to the user in a
list of search targets, or in the search box as a label. |
Yes |
android:icon |
If provided, this icon will be used in place of the label string. This
is provided in order to present logos or other non-textual banners. |
No |
android:hint |
This is the text to display in the search text field when no user text has been
entered. |
No |
android:searchButtonText |
If provided, this text will replace the default text in the "Search" button. |
No |
android:searchMode |
If provided and non-zero, sets additional modes for control of the search
presentation. The following mode bits are defined:
showSearchLabelAsBadge |
If set, this flag enables the display of the search target (label)
within the search bar. If this flag and showSearchIconAsBadge
(see below) are both not set, no badge will be shown. |
showSearchIconAsBadge |
If set, this flag enables the display of the search target (icon) within
the search bar. If this flag and showSearchLabelAsBadge
(see above) are both not set, no badge will be shown. If both flags
are set, showSearchIconAsBadge has precedence and the icon will be
shown. |
queryRewriteFromData |
If set, this flag causes the suggestion column SUGGEST_COLUMN_INTENT_DATA
to be considered as the text for suggestion query rewriting. This should
only be used when the values in SUGGEST_COLUMN_INTENT_DATA are suitable
for user inspection and editing - typically, HTTP/HTTPS Uri's. |
queryRewriteFromText |
If set, this flag causes the suggestion column SUGGEST_COLUMN_TEXT_1 to
be considered as the text for suggestion query rewriting. This should
be used for suggestions in which no query text is provided and the
SUGGEST_COLUMN_INTENT_DATA values are not suitable for user inspection
and editing. |
|
No |
android:inputType |
If provided, supplies a hint about the type of search text the user will be
entering. For most searches, in which free form text is expected, this attribute
need not be provided. Suitable values for this attribute are described in the
inputType attribute. |
No |
android:imeOptions |
If provided, supplies additional options for the input method.
For most searches, in which free form text is expected, this attribute
need not be provided, and will default to "actionSearch".
Suitable values for this attribute are described in the
imeOptions attribute. |
No |
Styleable Resources in your Metadata. It's possible to provide alternate strings
for your searchable application, in order to provide localization and/or to better visual
presentation on different device configurations. Each searchable activity has a single XML
metadata file, but any resource references can be replaced at runtime based on device
configuration, language setting, and other system inputs.
A concrete example is the "hint" text you supply using the android:searchHint attribute.
In portrait mode you'll have less screen space and may need to provide a shorter string, but
in landscape mode you can provide a longer, more descriptive hint. To do this, you'll need to
define two or more strings.xml files, in the following directories:
- .../res/values-land/strings.xml
- .../res/values-port/strings.xml
- .../res/values/strings.xml
For more complete documentation on this capability, see
Resources and
Internationalization: Alternate Resources.
Metadata for non-searchable activities. Activities which are part of a searchable
application, but don't implement search itself, require a bit of "glue" in order to cause
them to invoke search using your searchable activity as their primary context. If this is not
provided, then searches from these activities will use the system default search context.
The simplest way to specify this is to add a search reference element to the
application entry in the manifest file.
The value of this reference can be either of:
- The name of your searchable activity.
It is typically prefixed by '.' to indicate that it's in the same package.
- A "*" indicates that the system may select a default searchable activity, in which
case it will typically select web-based search.
Here is a snippet showing the necessary addition to the manifest entry for your
non-searchable activities.
<application>
<meta-data android:name="android.app.default_searchable"
android:value=".MySearchActivity" />
<!-- followed by activities, providers, etc... -->
</application>
You can also specify android.app.default_searchable on a per-activity basis, by including
the meta-data element (as shown above) in one or more activity sections. If found, these will
override the reference in the application section. The only reason to configure your application
this way would be if you wish to partition it into separate sections with different search
behaviors; Otherwise this configuration is not recommended.
Additional metadata for search suggestions. If you have defined a content provider
to generate search suggestions, you'll need to publish it to the system, and you'll need to
provide a bit of additional XML metadata in order to configure communications with it.
First, in your manifest, you'll add the
following lines.
<!-- Content provider for search suggestions -->
<provider android:name="YourSuggestionProviderClass"
android:authorities="your.suggestion.authority" />
Next, you'll add a few lines to your XML metadata file, as shown:
<!-- Required attribute for any suggestions provider -->
android:searchSuggestAuthority="your.suggestion.authority"
<!-- Optional attribute for configuring queries -->
android:searchSuggestSelection="field =?"
<!-- Optional attributes for configuring intent construction -->
android:searchSuggestIntentAction="intent action string"
android:searchSuggestIntentData="intent data Uri" />
Elements of search metadata that support suggestions:
Attribute | Description | Required? |
android:searchSuggestAuthority |
This value must match the authority string provided in the provider section
of your manifest. |
Yes |
android:searchSuggestPath |
If provided, this will be inserted in the suggestions query Uri, after the authority
you have provide but before the standard suggestions path. This is only required if
you have a single content provider issuing different types of suggestions (e.g. for
different data types) and you need a way to disambiguate the suggestions queries
when they are received. |
No |
android:searchSuggestSelection |
If provided, this value will be passed into your query function as the
selection parameter. Typically this will be a WHERE clause for your database,
and will contain a single question mark, which represents the actual query string
that has been typed by the user. However, you can also use any non-null value
to simply trigger the delivery of the query text (via selection arguments), and then
use the query text in any way appropriate for your provider (ignoring the actual
text of the selection parameter.) |
No |
android:searchSuggestIntentAction |
If provided, and not overridden by the selected suggestion, this value will be
placed in the action field of the {@link android.content.Intent Intent} when the
user clicks a suggestion. |
No |
---|
android:searchSuggestIntentData |
If provided, and not overridden by the selected suggestion, this value will be
placed in the data field of the {@link android.content.Intent Intent} when the user
clicks a suggestion. |
No |
Additional metadata for search action keys. For each action key that you would like to
define, you'll need to add an additional element defining that key, and using the attributes
discussed in Action Keys. A simple example is shown here:
<actionkey
android:keycode="KEYCODE_CALL"
android:queryActionMsg="call"
android:suggestActionMsg="call"
android:suggestActionMsgColumn="call_column" />
Elements of search metadata that support search action keys. Note that although each of the
action message elements are marked as optional, at least one must be present for the
action key to have any effect.
Attribute | Description | Required? |
android:keycode |
This attribute denotes the action key you wish to respond to. Note that not
all action keys are actually supported using this mechanism, as many of them are
used for typing, navigation, or system functions. This will be added to the
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to
your searchable activity. To examine the key code, use
{@link android.content.Intent#getIntExtra getIntExtra(SearchManager.ACTION_KEY)}.
Note, in addition to the keycode, you must also provide one or more of the action
specifier attributes. |
Yes |
android:queryActionMsg |
If you wish to handle an action key during normal search query entry, you
must define an action string here. This will be added to the
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to your
searchable activity. To examine the string, use
{@link android.content.Intent#getStringExtra
getStringExtra(SearchManager.ACTION_MSG)}. |
No |
android:suggestActionMsg |
If you wish to handle an action key while a suggestion is being displayed and
selected, there are two ways to handle this. If all of your suggestions
can handle the action key, you can simply define the action message using this
attribute. This will be added to the
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to
your searchable activity. To examine the string, use
{@link android.content.Intent#getStringExtra
getStringExtra(SearchManager.ACTION_MSG)}. |
No |
android:suggestActionMsgColumn |
If you wish to handle an action key while a suggestion is being displayed and
selected, but you do not wish to enable this action key for every suggestion,
then you can use this attribute to control it on a suggestion-by-suggestion basis.
First, you must define a column (and name it here) where your suggestions will
include the action string. Then, in your content provider, you must provide this
column, and when desired, provide data in this column.
The search manager will look at your suggestion cursor, using the string
provided here in order to select a column, and will use that to select a string from
the cursor. That string will be added to the
{@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH} intent that is passed to
your searchable activity. To examine the string, use
{@link android.content.Intent#getStringExtra
getStringExtra(SearchManager.ACTION_MSG)}. If the data does not exist for the
selection suggestion, the action key will be ignored. |
No |
Additional metadata for enabling voice search. To enable voice search for your
activity, you can add fields to the metadata that enable and configure voice search. When
enabled (and available on the device), a voice search button will be displayed in the
Search UI. Clicking this button will launch a voice search activity. When the user has
finished speaking, the voice search phrase will be transcribed into text and presented to the
searchable activity as if it were a typed query.
Elements of search metadata that support voice search:
Attribute | Description | Required? |
android:voiceSearchMode |
If provided and non-zero, enables voice search. (Voice search may not be
provided by the device, in which case these flags will have no effect.) The
following mode bits are defined:
showVoiceSearchButton |
If set, display a voice search button. This only takes effect if voice
search is available on the device. If set, then launchWebSearch or
launchRecognizer must also be set. |
launchWebSearch |
If set, the voice search button will take the user directly to a
built-in voice web search activity. Most applications will not use this
flag, as it will take the user away from the activity in which search
was invoked. |
launchRecognizer |
If set, the voice search button will take the user directly to a
built-in voice recording activity. This activity will prompt the user
to speak, transcribe the spoken text, and forward the resulting query
text to the searchable activity, just as if the user had typed it into
the search UI and clicked the search button. |
|
No |
android:voiceLanguageModel |
If provided, this specifies the language model that should be used by the voice
recognition system.
See {@link android.speech.RecognizerIntent#EXTRA_LANGUAGE_MODEL}
for more information. If not provided, the default value
{@link android.speech.RecognizerIntent#LANGUAGE_MODEL_FREE_FORM} will be used. |
No |
android:voicePromptText |
If provided, this specifies a prompt that will be displayed during voice input.
(If not provided, a default prompt will be displayed.) |
No |
android:voiceLanguage |
If provided, this specifies the spoken language to be expected. This is only
needed if it is different from the current value of
{@link java.util.Locale#getDefault()}.
|
No |
android:voiceMaxResults |
If provided, enforces the maximum number of results to return, including the "best"
result which will always be provided as the SEARCH intent's primary query. Must be
one or greater. Use {@link android.speech.RecognizerIntent#EXTRA_RESULTS}
to get the results from the intent. If not provided, the recognizer will choose
how many results to return. |
No |
Passing Search Context
In order to improve search experience, an application may wish to specify
additional data along with the search, such as local history or context. For
example, a maps search would be improved by including the current location.
In order to simplify the structure of your activities, this can be done using
the search manager.
Any data can be provided at the time the search is launched, as long as it
can be stored in a {@link android.os.Bundle Bundle} object.
To pass application data into the Search Manager, you'll need to override
{@link android.app.Activity#onSearchRequested onSearchRequested} as follows:
@Override
public boolean onSearchRequested() {
Bundle appData = new Bundle();
appData.put...();
appData.put...();
startSearch(null, false, appData);
return true;
}
To receive application data from the Search Manager, you'll extract it from
the {@link android.content.Intent#ACTION_SEARCH ACTION_SEARCH}
{@link android.content.Intent Intent} as follows:
final Bundle appData = queryIntent.getBundleExtra(SearchManager.APP_DATA);
if (appData != null) {
appData.get...();
appData.get...();
}
Protecting User Privacy
Many users consider their activities on the phone, including searches, to be private
information. Applications that implement search should take steps to protect users' privacy
wherever possible. This section covers two areas of concern, but you should consider your search
design carefully and take any additional steps necessary.
Don't send personal information to servers, and if you do, don't log it.
"Personal information" is information that can personally identify your users, such as name,
email address or billing information, or other data which can be reasonably linked to such
information. If your application implements search with the assistance of a server, try to
avoid sending personal information with your searches. For example, if you are searching for
businesses near a zip code, you don't need to send the user ID as well - just send the zip code
to the server. If you do need to send personal information, you should take steps to avoid
logging it. If you must log it, you should protect that data very carefully, and erase it as
soon as possible.
Provide the user with a way to clear their search history. The Search Manager helps
your application provide context-specific suggestions. Sometimes these suggestions are based
on previous searches, or other actions taken by the user in an earlier session. A user may not
wish for previous searches to be revealed to other users, for instance if they share their phone
with a friend. If your application provides suggestions that can reveal previous activities,
you should implement a "Clear History" menu, preference, or button. If you are using
{@link android.provider.SearchRecentSuggestions}, you can simply call its
{@link android.provider.SearchRecentSuggestions#clearHistory() clearHistory()} method from
your "Clear History" UI. If you are implementing your own form of recent suggestions, you'll
need to provide a similar a "clear history" API in your provider, and call it from your
"Clear History" UI. |