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DialogFragment.javaAPI DocAndroid 5.1 API21351Thu Mar 12 22:22:10 GMT 2015android.app

DialogFragment

public class DialogFragment extends Fragment implements DialogInterface.OnDismissListener, DialogInterface.OnCancelListener
A fragment that displays a dialog window, floating on top of its activity's window. This fragment contains a Dialog object, which it displays as appropriate based on the fragment's state. Control of the dialog (deciding when to show, hide, dismiss it) should be done through the API here, not with direct calls on the dialog.

Implementations should override this class and implement {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)} to supply the content of the dialog. Alternatively, they can override {@link #onCreateDialog(Bundle)} to create an entirely custom dialog, such as an AlertDialog, with its own content.

Topics covered here:

  1. Lifecycle
  2. Basic Dialog
  3. Alert Dialog
  4. Selecting Between Dialog or Embedding

Lifecycle

DialogFragment does various things to keep the fragment's lifecycle driving it, instead of the Dialog. Note that dialogs are generally autonomous entities -- they are their own window, receiving their own input events, and often deciding on their own when to disappear (by receiving a back key event or the user clicking on a button).

DialogFragment needs to ensure that what is happening with the Fragment and Dialog states remains consistent. To do this, it watches for dismiss events from the dialog and takes care of removing its own state when they happen. This means you should use {@link #show(FragmentManager, String)} or {@link #show(FragmentTransaction, String)} to add an instance of DialogFragment to your UI, as these keep track of how DialogFragment should remove itself when the dialog is dismissed.

Basic Dialog

The simplest use of DialogFragment is as a floating container for the fragment's view hierarchy. A simple implementation may look like this: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialog.java dialog}

An example showDialog() method on the Activity could be: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialog.java add_dialog}

This removes any currently shown dialog, creates a new DialogFragment with an argument, and shows it as a new state on the back stack. When the transaction is popped, the current DialogFragment and its Dialog will be destroyed, and the previous one (if any) re-shown. Note that in this case DialogFragment will take care of popping the transaction of the Dialog is dismissed separately from it.

Alert Dialog

Instead of (or in addition to) implementing {@link #onCreateView} to generate the view hierarchy inside of a dialog, you may implement {@link #onCreateDialog(Bundle)} to create your own custom Dialog object.

This is most useful for creating an {@link AlertDialog}, allowing you to display standard alerts to the user that are managed by a fragment. A simple example implementation of this is: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentAlertDialog.java dialog}

The activity creating this fragment may have the following methods to show the dialog and receive results from it: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentAlertDialog.java activity}

Note that in this case the fragment is not placed on the back stack, it is just added as an indefinitely running fragment. Because dialogs normally are modal, this will still operate as a back stack, since the dialog will capture user input until it is dismissed. When it is dismissed, DialogFragment will take care of removing itself from its fragment manager.

Selecting Between Dialog or Embedding

A DialogFragment can still optionally be used as a normal fragment, if desired. This is useful if you have a fragment that in some cases should be shown as a dialog and others embedded in a larger UI. This behavior will normally be automatically selected for you based on how you are using the fragment, but can be customized with {@link #setShowsDialog(boolean)}.

For example, here is a simple dialog fragment: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialogOrActivity.java dialog}

An instance of this fragment can be created and shown as a dialog: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialogOrActivity.java show_dialog}

It can also be added as content in a view hierarchy: {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialogOrActivity.java embed}

Fields Summary
public static final int
STYLE_NORMAL
Style for {@link #setStyle(int, int)}: a basic, normal dialog.
public static final int
STYLE_NO_TITLE
Style for {@link #setStyle(int, int)}: don't include a title area.
public static final int
STYLE_NO_FRAME
Style for {@link #setStyle(int, int)}: don't draw any frame at all; the view hierarchy returned by {@link #onCreateView} is entirely responsible for drawing the dialog.
public static final int
STYLE_NO_INPUT
Style for {@link #setStyle(int, int)}: like {@link #STYLE_NO_FRAME}, but also disables all input to the dialog. The user can not touch it, and its window will not receive input focus.
private static final String
SAVED_DIALOG_STATE_TAG
private static final String
SAVED_STYLE
private static final String
SAVED_THEME
private static final String
SAVED_CANCELABLE
private static final String
SAVED_SHOWS_DIALOG
private static final String
SAVED_BACK_STACK_ID
int
mStyle
int
mTheme
boolean
mCancelable
boolean
mShowsDialog
int
mBackStackId
Dialog
mDialog
boolean
mViewDestroyed
boolean
mDismissed
boolean
mShownByMe
Constructors Summary
public DialogFragment()
Methods Summary
public voiddismiss()
Dismiss the fragment and its dialog. If the fragment was added to the back stack, all back stack state up to and including this entry will be popped. Otherwise, a new transaction will be committed to remove the fragment.

        dismissInternal(false);
public voiddismissAllowingStateLoss()
Version of {@link #dismiss()} that uses {@link FragmentTransaction#commitAllowingStateLoss() FragmentTransaction.commitAllowingStateLoss()}. See linked documentation for further details.

        dismissInternal(true);
voiddismissInternal(boolean allowStateLoss)

        if (mDismissed) {
            return;
        }
        mDismissed = true;
        mShownByMe = false;
        if (mDialog != null) {
            mDialog.dismiss();
            mDialog = null;
        }
        mViewDestroyed = true;
        if (mBackStackId >= 0) {
            getFragmentManager().popBackStack(mBackStackId,
                    FragmentManager.POP_BACK_STACK_INCLUSIVE);
            mBackStackId = -1;
        } else {
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.remove(this);
            if (allowStateLoss) {
                ft.commitAllowingStateLoss();
            } else {
                ft.commit();
            }
        }
public voiddump(java.lang.String prefix, java.io.FileDescriptor fd, java.io.PrintWriter writer, java.lang.String[] args)

        super.dump(prefix, fd, writer, args);
        writer.print(prefix); writer.println("DialogFragment:");
        writer.print(prefix); writer.print("  mStyle="); writer.print(mStyle);
                writer.print(" mTheme=0x"); writer.println(Integer.toHexString(mTheme));
        writer.print(prefix); writer.print("  mCancelable="); writer.print(mCancelable);
                writer.print(" mShowsDialog="); writer.print(mShowsDialog);
                writer.print(" mBackStackId="); writer.println(mBackStackId);
        writer.print(prefix); writer.print("  mDialog="); writer.println(mDialog);
        writer.print(prefix); writer.print("  mViewDestroyed="); writer.print(mViewDestroyed);
                writer.print(" mDismissed="); writer.print(mDismissed);
                writer.print(" mShownByMe="); writer.println(mShownByMe);
public DialoggetDialog()

        return mDialog;
public android.view.LayoutInflatergetLayoutInflater(android.os.Bundle savedInstanceState)

hide

        if (!mShowsDialog) {
            return super.getLayoutInflater(savedInstanceState);
        }

        mDialog = onCreateDialog(savedInstanceState);
        switch (mStyle) {
            case STYLE_NO_INPUT:
                mDialog.getWindow().addFlags(
                        WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE |
                        WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE);
                // fall through...
            case STYLE_NO_FRAME:
            case STYLE_NO_TITLE:
                mDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        }
        if (mDialog != null) {
            return (LayoutInflater)mDialog.getContext().getSystemService(
                    Context.LAYOUT_INFLATER_SERVICE);
        }
        return (LayoutInflater)mActivity.getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);
public booleangetShowsDialog()
Return the current value of {@link #setShowsDialog(boolean)}.

        return mShowsDialog;
public intgetTheme()

        return mTheme;
public booleanisCancelable()
Return the current value of {@link #setCancelable(boolean)}.

        return mCancelable;
public voidonActivityCreated(android.os.Bundle savedInstanceState)

        super.onActivityCreated(savedInstanceState);

        if (!mShowsDialog) {
            return;
        }

        View view = getView();
        if (view != null) {
            if (view.getParent() != null) {
                throw new IllegalStateException("DialogFragment can not be attached to a container view");
            }
            mDialog.setContentView(view);
        }
        mDialog.setOwnerActivity(getActivity());
        mDialog.setCancelable(mCancelable);
        if (!mDialog.takeCancelAndDismissListeners("DialogFragment", this, this)) {
            throw new IllegalStateException(
                    "You can not set Dialog's OnCancelListener or OnDismissListener");
        }
        if (savedInstanceState != null) {
            Bundle dialogState = savedInstanceState.getBundle(SAVED_DIALOG_STATE_TAG);
            if (dialogState != null) {
                mDialog.onRestoreInstanceState(dialogState);
            }
        }
public voidonAttach(Activity activity)

        super.onAttach(activity);
        if (!mShownByMe) {
            // If not explicitly shown through our API, take this as an
            // indication that the dialog is no longer dismissed.
            mDismissed = false;
        }
public voidonCancel(android.content.DialogInterface dialog)
public voidonCreate(android.os.Bundle savedInstanceState)

        super.onCreate(savedInstanceState);

        mShowsDialog = mContainerId == 0;

        if (savedInstanceState != null) {
            mStyle = savedInstanceState.getInt(SAVED_STYLE, STYLE_NORMAL);
            mTheme = savedInstanceState.getInt(SAVED_THEME, 0);
            mCancelable = savedInstanceState.getBoolean(SAVED_CANCELABLE, true);
            mShowsDialog = savedInstanceState.getBoolean(SAVED_SHOWS_DIALOG, mShowsDialog);
            mBackStackId = savedInstanceState.getInt(SAVED_BACK_STACK_ID, -1);
        }
public DialogonCreateDialog(android.os.Bundle savedInstanceState)
Override to build your own custom Dialog container. This is typically used to show an AlertDialog instead of a generic Dialog; when doing so, {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)} does not need to be implemented since the AlertDialog takes care of its own content.

This method will be called after {@link #onCreate(Bundle)} and before {@link #onCreateView(LayoutInflater, ViewGroup, Bundle)}. The default implementation simply instantiates and returns a {@link Dialog} class.

Note: DialogFragment own the {@link Dialog#setOnCancelListener Dialog.setOnCancelListener} and {@link Dialog#setOnDismissListener Dialog.setOnDismissListener} callbacks. You must not set them yourself. To find out about these events, override {@link #onCancel(DialogInterface)} and {@link #onDismiss(DialogInterface)}.

param
savedInstanceState The last saved instance state of the Fragment, or null if this is a freshly created Fragment.
return
Return a new Dialog instance to be displayed by the Fragment.

        return new Dialog(getActivity(), getTheme());
public voidonDestroyView()
Remove dialog.

        super.onDestroyView();
        if (mDialog != null) {
            // Set removed here because this dismissal is just to hide
            // the dialog -- we don't want this to cause the fragment to
            // actually be removed.
            mViewDestroyed = true;
            mDialog.dismiss();
            mDialog = null;
        }
public voidonDetach()

        super.onDetach();
        if (!mShownByMe && !mDismissed) {
            // The fragment was not shown by a direct call here, it is not
            // dismissed, and now it is being detached...  well, okay, thou
            // art now dismissed.  Have fun.
            mDismissed = true;
        }
public voidonDismiss(android.content.DialogInterface dialog)

        if (!mViewDestroyed) {
            // Note: we need to use allowStateLoss, because the dialog
            // dispatches this asynchronously so we can receive the call
            // after the activity is paused.  Worst case, when the user comes
            // back to the activity they see the dialog again.
            dismissInternal(true);
        }
public voidonSaveInstanceState(android.os.Bundle outState)

        super.onSaveInstanceState(outState);
        if (mDialog != null) {
            Bundle dialogState = mDialog.onSaveInstanceState();
            if (dialogState != null) {
                outState.putBundle(SAVED_DIALOG_STATE_TAG, dialogState);
            }
        }
        if (mStyle != STYLE_NORMAL) {
            outState.putInt(SAVED_STYLE, mStyle);
        }
        if (mTheme != 0) {
            outState.putInt(SAVED_THEME, mTheme);
        }
        if (!mCancelable) {
            outState.putBoolean(SAVED_CANCELABLE, mCancelable);
        }
        if (!mShowsDialog) {
            outState.putBoolean(SAVED_SHOWS_DIALOG, mShowsDialog);
        }
        if (mBackStackId != -1) {
            outState.putInt(SAVED_BACK_STACK_ID, mBackStackId);
        }
public voidonStart()

        super.onStart();
        if (mDialog != null) {
            mViewDestroyed = false;
            mDialog.show();
        }
public voidonStop()

        super.onStop();
        if (mDialog != null) {
            mDialog.hide();
        }
public voidsetCancelable(boolean cancelable)
Control whether the shown Dialog is cancelable. Use this instead of directly calling {@link Dialog#setCancelable(boolean) Dialog.setCancelable(boolean)}, because DialogFragment needs to change its behavior based on this.

param
cancelable If true, the dialog is cancelable. The default is true.

        mCancelable = cancelable;
        if (mDialog != null) mDialog.setCancelable(cancelable);
public voidsetShowsDialog(boolean showsDialog)
Controls whether this fragment should be shown in a dialog. If not set, no Dialog will be created in {@link #onActivityCreated(Bundle)}, and the fragment's view hierarchy will thus not be added to it. This allows you to instead use it as a normal fragment (embedded inside of its activity).

This is normally set for you based on whether the fragment is associated with a container view ID passed to {@link FragmentTransaction#add(int, Fragment) FragmentTransaction.add(int, Fragment)}. If the fragment was added with a container, setShowsDialog will be initialized to false; otherwise, it will be true.

param
showsDialog If true, the fragment will be displayed in a Dialog. If false, no Dialog will be created and the fragment's view hierarchly left undisturbed.

        mShowsDialog = showsDialog;
public voidsetStyle(int style, int theme)
Call to customize the basic appearance and behavior of the fragment's dialog. This can be used for some common dialog behaviors, taking care of selecting flags, theme, and other options for you. The same effect can be achieve by manually setting Dialog and Window attributes yourself. Calling this after the fragment's Dialog is created will have no effect.

param
style Selects a standard style: may be {@link #STYLE_NORMAL}, {@link #STYLE_NO_TITLE}, {@link #STYLE_NO_FRAME}, or {@link #STYLE_NO_INPUT}.
param
theme Optional custom theme. If 0, an appropriate theme (based on the style) will be selected for you.

        mStyle = style;
        if (mStyle == STYLE_NO_FRAME || mStyle == STYLE_NO_INPUT) {
            mTheme = com.android.internal.R.style.Theme_DeviceDefault_Dialog_NoFrame;
        }
        if (theme != 0) {
            mTheme = theme;
        }
public voidshow(FragmentManager manager, java.lang.String tag)
Display the dialog, adding the fragment to the given FragmentManager. This is a convenience for explicitly creating a transaction, adding the fragment to it with the given tag, and committing it. This does not add the transaction to the back stack. When the fragment is dismissed, a new transaction will be executed to remove it from the activity.

param
manager The FragmentManager this fragment will be added to.
param
tag The tag for this fragment, as per {@link FragmentTransaction#add(Fragment, String) FragmentTransaction.add}.

        mDismissed = false;
        mShownByMe = true;
        FragmentTransaction ft = manager.beginTransaction();
        ft.add(this, tag);
        ft.commit();
public intshow(FragmentTransaction transaction, java.lang.String tag)
Display the dialog, adding the fragment using an existing transaction and then committing the transaction.

param
transaction An existing transaction in which to add the fragment.
param
tag The tag for this fragment, as per {@link FragmentTransaction#add(Fragment, String) FragmentTransaction.add}.
return
Returns the identifier of the committed transaction, as per {@link FragmentTransaction#commit() FragmentTransaction.commit()}.

        mDismissed = false;
        mShownByMe = true;
        transaction.add(this, tag);
        mViewDestroyed = false;
        mBackStackId = transaction.commit();
        return mBackStackId;