FileDocCategorySizeDatePackage
CardEmulation.javaAPI DocAndroid 5.1 API25303Thu Mar 12 22:22:10 GMT 2015android.nfc.cardemulation

CardEmulation

public final class CardEmulation extends Object
This class can be used to query the state of NFC card emulation services. For a general introduction into NFC card emulation, please read the NFC card emulation developer guide.

Use of this class requires the {@link PackageManager#FEATURE_NFC_HOST_CARD_EMULATION} to be present on the device.

Fields Summary
static final String
TAG
public static final String
ACTION_CHANGE_DEFAULT
Activity action: ask the user to change the default card emulation service for a certain category. This will show a dialog that asks the user whether he wants to replace the current default service with the service identified with the ComponentName specified in {@link #EXTRA_SERVICE_COMPONENT}, for the category specified in {@link #EXTRA_CATEGORY}
public static final String
EXTRA_CATEGORY
The category extra for {@link #ACTION_CHANGE_DEFAULT}.
public static final String
EXTRA_SERVICE_COMPONENT
The service {@link ComponentName} object passed in as an extra for {@link #ACTION_CHANGE_DEFAULT}.
public static final String
CATEGORY_PAYMENT
Category used for NFC payment services.
public static final String
CATEGORY_OTHER
Category that can be used for all other card emulation services.
public static final int
SELECTION_MODE_PREFER_DEFAULT
Return value for {@link #getSelectionModeForCategory(String)}.

In this mode, the user has set a default service for this category.

When using ISO-DEP card emulation with {@link HostApduService} or {@link OffHostApduService}, if a remote NFC device selects any of the Application IDs (AIDs) that the default service has registered in this category, that service will automatically be bound to to handle the transaction.

public static final int
SELECTION_MODE_ALWAYS_ASK
Return value for {@link #getSelectionModeForCategory(String)}.

In this mode, when using ISO-DEP card emulation with {@link HostApduService} or {@link OffHostApduService}, whenever an Application ID (AID) of this category is selected, the user is asked which service he wants to use to handle the transaction, even if there is only one matching service.

public static final int
SELECTION_MODE_ASK_IF_CONFLICT
Return value for {@link #getSelectionModeForCategory(String)}.

In this mode, when using ISO-DEP card emulation with {@link HostApduService} or {@link OffHostApduService}, the user will only be asked to select a service if the Application ID (AID) selected by the reader has been registered by multiple services. If there is only one service that has registered for the AID, that service will be invoked directly.

static boolean
sIsInitialized
static HashMap
sCardEmus
static android.nfc.INfcCardEmulation
sService
final android.content.Context
mContext
Constructors Summary
private CardEmulation(android.content.Context context, android.nfc.INfcCardEmulation service)


         
        mContext = context.getApplicationContext();
        sService = service;
Methods Summary
public booleancategoryAllowsForegroundPreference(java.lang.String category)
Returns whether the user has allowed AIDs registered in the specified category to be handled by a service that is preferred by the foreground application, instead of by a pre-configured default. Foreground applications can set such preferences using the {@link #setPreferredService(Activity, ComponentName)} method.

param
category The category, e.g. {@link #CATEGORY_PAYMENT}
return
whether AIDs in the category can be handled by a service specified by the foreground app.

        if (CATEGORY_PAYMENT.equals(category)) {
            boolean preferForeground = false;
            try {
                preferForeground = Settings.Secure.getInt(mContext.getContentResolver(),
                        Settings.Secure.NFC_PAYMENT_FOREGROUND) != 0;
            } catch (SettingNotFoundException e) {
            }
            return preferForeground;
        } else {
            // Allowed for all other categories
            return true;
        }
public java.util.ListgetAidsForService(android.content.ComponentName service, java.lang.String category)
Retrieves the currently registered AIDs for the specified category for a service.

Note that this will only return AIDs that were dynamically registered using {@link #registerAidsForService(ComponentName, String, List)} method. It will *not* return AIDs that were statically registered in the manifest.

param
service The component name of the service
param
category The category for which the AIDs were registered, e.g. {@link #CATEGORY_PAYMENT}
return
The list of AIDs registered for this category, or null if it couldn't be found.

        try {
            AidGroup group =  sService.getAidGroupForService(UserHandle.myUserId(), service,
                    category);
            return (group != null ? group.getAids() : null);
        } catch (RemoteException e) {
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return null;
            }
            try {
                AidGroup group = sService.getAidGroupForService(UserHandle.myUserId(), service,
                        category);
                return (group != null ? group.getAids() : null);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return null;
            }
        }
public static synchronized android.nfc.cardemulation.CardEmulationgetInstance(android.nfc.NfcAdapter adapter)
Helper to get an instance of this class.

param
adapter A reference to an NfcAdapter object.
return

        if (adapter == null) throw new NullPointerException("NfcAdapter is null");
        Context context = adapter.getContext();
        if (context == null) {
            Log.e(TAG, "NfcAdapter context is null.");
            throw new UnsupportedOperationException();
        }
        if (!sIsInitialized) {
            IPackageManager pm = ActivityThread.getPackageManager();
            if (pm == null) {
                Log.e(TAG, "Cannot get PackageManager");
                throw new UnsupportedOperationException();
            }
            try {
                if (!pm.hasSystemFeature(PackageManager.FEATURE_NFC_HOST_CARD_EMULATION)) {
                    Log.e(TAG, "This device does not support card emulation");
                    throw new UnsupportedOperationException();
                }
            } catch (RemoteException e) {
                Log.e(TAG, "PackageManager query failed.");
                throw new UnsupportedOperationException();
            }
            sIsInitialized = true;
        }
        CardEmulation manager = sCardEmus.get(context);
        if (manager == null) {
            // Get card emu service
            INfcCardEmulation service = adapter.getCardEmulationService();
            if (service == null) {
                Log.e(TAG, "This device does not implement the INfcCardEmulation interface.");
                throw new UnsupportedOperationException();
            }
            manager = new CardEmulation(context, service);
            sCardEmus.put(context, manager);
        }
        return manager;
public intgetSelectionModeForCategory(java.lang.String category)
Returns the service selection mode for the passed in category. Valid return values are:

{@link #SELECTION_MODE_PREFER_DEFAULT} the user has requested a default service for this category, which will be preferred.

{@link #SELECTION_MODE_ALWAYS_ASK} the user has requested to be asked every time what service he would like to use in this category.

{@link #SELECTION_MODE_ASK_IF_CONFLICT} the user will only be asked to pick a service if there is a conflict.

param
category The category, for example {@link #CATEGORY_PAYMENT}
return
the selection mode for the passed in category

        if (CATEGORY_PAYMENT.equals(category)) {
            String defaultComponent = Settings.Secure.getString(mContext.getContentResolver(),
                    Settings.Secure.NFC_PAYMENT_DEFAULT_COMPONENT);
            if (defaultComponent != null) {
                return SELECTION_MODE_PREFER_DEFAULT;
            } else {
                return SELECTION_MODE_ALWAYS_ASK;
            }
        } else {
            return SELECTION_MODE_ASK_IF_CONFLICT;
        }
public java.util.ListgetServices(java.lang.String category)

hide

        try {
            return sService.getServices(UserHandle.myUserId(), category);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return null;
            }
            try {
                return sService.getServices(UserHandle.myUserId(), category);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return null;
            }
        }
public booleanisDefaultServiceForAid(android.content.ComponentName service, java.lang.String aid)
Allows an application to query whether a service is currently the default handler for a specified ISO7816-4 Application ID.

param
service The ComponentName of the service
param
aid The ISO7816-4 Application ID
return
whether the service is the default handler for the specified AID

Requires the {@link android.Manifest.permission#NFC} permission.

        try {
            return sService.isDefaultServiceForAid(UserHandle.myUserId(), service, aid);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.isDefaultServiceForAid(UserHandle.myUserId(), service, aid);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleanisDefaultServiceForCategory(android.content.ComponentName service, java.lang.String category)
Allows an application to query whether a service is currently the default service to handle a card emulation category.

Note that if {@link #getSelectionModeForCategory(String)} returns {@link #SELECTION_MODE_ALWAYS_ASK} or {@link #SELECTION_MODE_ASK_IF_CONFLICT}, this method will always return false. That is because in these selection modes a default can't be set at the category level. For categories where the selection mode is {@link #SELECTION_MODE_ALWAYS_ASK} or {@link #SELECTION_MODE_ASK_IF_CONFLICT}, use {@link #isDefaultServiceForAid(ComponentName, String)} to determine whether a service is the default for a specific AID.

param
service The ComponentName of the service
param
category The category
return
whether service is currently the default service for the category.

Requires the {@link android.Manifest.permission#NFC} permission.

        try {
            return sService.isDefaultServiceForCategory(UserHandle.myUserId(), service, category);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.isDefaultServiceForCategory(UserHandle.myUserId(), service,
                        category);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
        }
public static booleanisValidAid(java.lang.String aid)
A valid AID according to ISO/IEC 7816-4:
  • Has >= 5 bytes and <=16 bytes (>=10 hex chars and <= 32 hex chars)
  • Consist of only hex characters
  • Additionally, we allow an asterisk at the end, to indicate a prefix

hide

        if (aid == null)
            return false;

        // If a prefix AID, the total length must be odd (even # of AID chars + '*')
        if (aid.endsWith("*") && ((aid.length() % 2) == 0)) {
            Log.e(TAG, "AID " + aid + " is not a valid AID.");
            return false;
        }

        // If not a prefix AID, the total length must be even (even # of AID chars)
        if (!aid.endsWith("*") && ((aid.length() % 2) != 0)) {
            Log.e(TAG, "AID " + aid + " is not a valid AID.");
            return false;
        }

        // Verify hex characters
        if (!aid.matches("[0-9A-Fa-f]{10,32}\\*?")) {
            Log.e(TAG, "AID " + aid + " is not a valid AID.");
            return false;
        }

        return true;
voidrecoverService()

        NfcAdapter adapter = NfcAdapter.getDefaultAdapter(mContext);
        sService = adapter.getCardEmulationService();
public booleanregisterAidsForService(android.content.ComponentName service, java.lang.String category, java.util.List aids)
Registers a list of AIDs for a specific category for the specified service.

If a list of AIDs for that category was previously registered for this service (either statically through the manifest, or dynamically by using this API), that list of AIDs will be replaced with this one.

Note that you can only register AIDs for a service that is running under the same UID as the caller of this API. Typically this means you need to call this from the same package as the service itself, though UIDs can also be shared between packages using shared UIDs.

param
service The component name of the service
param
category The category of AIDs to be registered
param
aids A list containing the AIDs to be registered
return
whether the registration was successful.

        AidGroup aidGroup = new AidGroup(aids, category);
        try {
            return sService.registerAidGroupForService(UserHandle.myUserId(), service, aidGroup);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.registerAidGroupForService(UserHandle.myUserId(), service,
                        aidGroup);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleanremoveAidsForService(android.content.ComponentName service, java.lang.String category)
Removes a previously registered list of AIDs for the specified category for the service provided.

Note that this will only remove AIDs that were dynamically registered using the {@link #registerAidsForService(ComponentName, String, List)} method. It will *not* remove AIDs that were statically registered in the manifest. If dynamically registered AIDs are removed using this method, and a statically registered AID group for the same category exists in the manifest, the static AID group will become active again.

param
service The component name of the service
param
category The category of the AIDs to be removed, e.g. {@link #CATEGORY_PAYMENT}
return
whether the group was successfully removed.

        try {
            return sService.removeAidGroupForService(UserHandle.myUserId(), service, category);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.removeAidGroupForService(UserHandle.myUserId(), service, category);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleansetDefaultForNextTap(android.content.ComponentName service)

hide

        try {
            return sService.setDefaultForNextTap(UserHandle.myUserId(), service);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.setDefaultForNextTap(UserHandle.myUserId(), service);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleansetDefaultServiceForCategory(android.content.ComponentName service, java.lang.String category)

hide

        try {
            return sService.setDefaultServiceForCategory(UserHandle.myUserId(), service, category);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.setDefaultServiceForCategory(UserHandle.myUserId(), service,
                        category);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleansetPreferredService(android.app.Activity activity, android.content.ComponentName service)
Allows a foreground application to specify which card emulation service should be preferred while a specific Activity is in the foreground.

The specified Activity must currently be in resumed state. A good paradigm is to call this method in your {@link Activity#onResume}, and to call {@link #unsetPreferredService(Activity)} in your {@link Activity#onPause}.

This method call will fail in two specific scenarios:

  • If the service registers one or more AIDs in the {@link #CATEGORY_PAYMENT} category, but the user has indicated that foreground apps are not allowed to override the default payment service.
  • If the service registers one or more AIDs in the {@link #CATEGORY_OTHER} category that are also handled by the default payment service, and the user has indicated that foreground apps are not allowed to override the default payment service.

Use {@link #categoryAllowsForegroundPreference(String)} to determine whether foreground apps can override the default payment service.

Note that this preference is not persisted by the OS, and hence must be called every time the Activity is resumed.

param
activity The activity which prefers this service to be invoked
param
service The service to be preferred while this activity is in the foreground
return
whether the registration was successful

        // Verify the activity is in the foreground before calling into NfcService
        if (activity == null || service == null) {
            throw new NullPointerException("activity or service or category is null");
        }
        if (!activity.isResumed()) {
            throw new IllegalArgumentException("Activity must be resumed.");
        }
        try {
            return sService.setPreferredService(service);
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.setPreferredService(service);
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleansupportsAidPrefixRegistration()
Some devices may allow an application to register all AIDs that starts with a certain prefix, e.g. "A000000004*" to register all MasterCard AIDs. Use this method to determine whether this device supports registering AID prefixes.

return
whether AID prefix registering is supported on this device.

        try {
            return sService.supportsAidPrefixRegistration();
        } catch (RemoteException e) {
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.supportsAidPrefixRegistration();
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }
public booleanunsetPreferredService(android.app.Activity activity)
Unsets the preferred service for the specified Activity.

Note that the specified Activity must still be in resumed state at the time of this call. A good place to call this method is in your {@link Activity#onPause} implementation.

param
activity The activity which the service was registered for
return
true when successful

        if (activity == null) {
            throw new NullPointerException("activity is null");
        }
        if (!activity.isResumed()) {
            throw new IllegalArgumentException("Activity must be resumed.");
        }
        try {
            return sService.unsetPreferredService();
        } catch (RemoteException e) {
            // Try one more time
            recoverService();
            if (sService == null) {
                Log.e(TAG, "Failed to recover CardEmulationService.");
                return false;
            }
            try {
                return sService.unsetPreferredService();
            } catch (RemoteException ee) {
                Log.e(TAG, "Failed to reach CardEmulationService.");
                return false;
            }
        }