Java tutorial
/* * Copyright (C) 2010 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.app; import android.annotation.UnsupportedAppUsage; import android.content.Context; import android.content.DialogInterface; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.Window; import android.view.WindowManager; import java.io.FileDescriptor; import java.io.PrintWriter; /** * 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. * * <p>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. * * <p>Topics covered here: * <ol> * <li><a href="#Lifecycle">Lifecycle</a> * <li><a href="#BasicDialog">Basic Dialog</a> * <li><a href="#AlertDialog">Alert Dialog</a> * <li><a href="#DialogOrEmbed">Selecting Between Dialog or Embedding</a> * </ol> * * <a name="Lifecycle"></a> * <h3>Lifecycle</h3> * * <p>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). * * <p>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. * * <a name="BasicDialog"></a> * <h3>Basic Dialog</h3> * * <p>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} * * <p>An example showDialog() method on the Activity could be: * * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialog.java * add_dialog} * * <p>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. * * <a name="AlertDialog"></a> * <h3>Alert Dialog</h3> * * <p>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. * * <p>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} * * <p>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} * * <p>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. * * <a name="DialogOrEmbed"></a> * <h3>Selecting Between Dialog or Embedding</h3> * * <p>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)}. * * <p>For example, here is a simple dialog fragment: * * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialogOrActivity.java * dialog} * * <p>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} * * <p>It can also be added as content in a view hierarchy: * * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/FragmentDialogOrActivity.java * embed} * * @deprecated Use the <a href="{@docRoot}tools/extras/support-library.html">Support Library</a> * {@link android.support.v4.app.DialogFragment} for consistent behavior across all devices * and access to <a href="{@docRoot}topic/libraries/architecture/lifecycle.html">Lifecycle</a>. */ @Deprecated public class DialogFragment extends Fragment implements DialogInterface.OnCancelListener, DialogInterface.OnDismissListener { /** * Style for {@link #setStyle(int, int)}: a basic, * normal dialog. */ public static final int STYLE_NORMAL = 0; /** * Style for {@link #setStyle(int, int)}: don't include * a title area. */ public static final int STYLE_NO_TITLE = 1; /** * 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_FRAME = 2; /** * 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. */ public static final int STYLE_NO_INPUT = 3; private static final String SAVED_DIALOG_STATE_TAG = "android:savedDialogState"; private static final String SAVED_STYLE = "android:style"; private static final String SAVED_THEME = "android:theme"; private static final String SAVED_CANCELABLE = "android:cancelable"; private static final String SAVED_SHOWS_DIALOG = "android:showsDialog"; private static final String SAVED_BACK_STACK_ID = "android:backStackId"; int mStyle = STYLE_NORMAL; int mTheme = 0; boolean mCancelable = true; boolean mShowsDialog = true; @UnsupportedAppUsage int mBackStackId = -1; Dialog mDialog; @UnsupportedAppUsage boolean mViewDestroyed; @UnsupportedAppUsage boolean mDismissed; @UnsupportedAppUsage boolean mShownByMe; public DialogFragment() { } /** * 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. */ public void setStyle(int style, int theme) { 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; } } /** * 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 * <em>not</em> 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}. */ public void show(FragmentManager manager, String tag) { mDismissed = false; mShownByMe = true; FragmentTransaction ft = manager.beginTransaction(); ft.add(this, tag); ft.commit(); } /** {@hide} */ @UnsupportedAppUsage public void showAllowingStateLoss(FragmentManager manager, String tag) { mDismissed = false; mShownByMe = true; FragmentTransaction ft = manager.beginTransaction(); ft.add(this, tag); ft.commitAllowingStateLoss(); } /** * 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()}. */ public int show(FragmentTransaction transaction, String tag) { mDismissed = false; mShownByMe = true; transaction.add(this, tag); mViewDestroyed = false; mBackStackId = transaction.commit(); return mBackStackId; } /** * 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. */ public void dismiss() { dismissInternal(false); } /** * Version of {@link #dismiss()} that uses * {@link FragmentTransaction#commitAllowingStateLoss() * FragmentTransaction.commitAllowingStateLoss()}. See linked * documentation for further details. */ public void dismissAllowingStateLoss() { dismissInternal(true); } void dismissInternal(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 Dialog getDialog() { return mDialog; } public int getTheme() { return mTheme; } /** * 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. */ public void setCancelable(boolean cancelable) { mCancelable = cancelable; if (mDialog != null) mDialog.setCancelable(cancelable); } /** * Return the current value of {@link #setCancelable(boolean)}. */ public boolean isCancelable() { return mCancelable; } /** * 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). * * <p>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. */ public void setShowsDialog(boolean showsDialog) { mShowsDialog = showsDialog; } /** * Return the current value of {@link #setShowsDialog(boolean)}. */ public boolean getShowsDialog() { return mShowsDialog; } @Override public void onAttach(Context context) { super.onAttach(context); if (!mShownByMe) { // If not explicitly shown through our API, take this as an // indication that the dialog is no longer dismissed. mDismissed = false; } } @Override public void onDetach() { 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; } } @Override public void onCreate(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); } } /** @hide */ @Override public LayoutInflater onGetLayoutInflater(Bundle savedInstanceState) { if (!mShowsDialog) { return super.onGetLayoutInflater(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) mHost.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); } /** * 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. * * <p>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. * * <p><em>Note: DialogFragment own the {@link Dialog#setOnCancelListener * Dialog.setOnCancelListener} and {@link Dialog#setOnDismissListener * Dialog.setOnDismissListener} callbacks. You must not set them yourself.</em> * To find out about these events, override {@link #onCancel(DialogInterface)} * and {@link #onDismiss(DialogInterface)}.</p> * * @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. */ public Dialog onCreateDialog(Bundle savedInstanceState) { return new Dialog(getActivity(), getTheme()); } public void onCancel(DialogInterface dialog) { } public void onDismiss(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); } } @Override public void onActivityCreated(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); } final Activity activity = getActivity(); if (activity != null) { mDialog.setOwnerActivity(activity); } 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); } } } @Override public void onStart() { super.onStart(); if (mDialog != null) { mViewDestroyed = false; mDialog.show(); } } @Override public void onSaveInstanceState(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); } } @Override public void onStop() { super.onStop(); if (mDialog != null) { mDialog.hide(); } } /** * Remove dialog. */ @Override public void onDestroyView() { 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; } } @Override public void dump(String prefix, FileDescriptor fd, PrintWriter writer, 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); } }