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/* * Copyright (C) 2012 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.support.v4.app; import android.app.Activity; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.pm.ActivityInfo; import android.content.pm.PackageManager; import android.content.pm.PackageManager.NameNotFoundException; /** * NavUtils provides helper functionality for applications implementing * recommended Android UI navigation patterns. For information about recommended * navigation patterns see * <a href="{@docRoot}guide/topics/fundamentals/tasks-and-back-stack.html">Tasks and Back Stack</a> * from the developer guide and <a href="{@docRoot}design/patterns/navigation.html">Navigation</a> * from the design guide. */ public class NavUtils { private static final String TAG = "NavUtils"; public static final String PARENT_ACTIVITY = "android.support.PARENT_ACTIVITY"; /** * Returns true if sourceActivity should recreate the task when navigating 'up' * by using targetIntent. * * <p>If this method returns false the app can trivially call * {@link #navigateUpTo(Activity, Intent)} using the same parameters to correctly perform * up navigation. If this method returns false, the app should synthesize a new task stack * by using {@link TaskStackBuilder} or another similar mechanism to perform up navigation.</p> * * @param sourceActivity The current activity from which the user is attempting to navigate up * @param targetIntent An intent representing the target destination for up navigation * @return true if navigating up should recreate a new task stack, false if the same task * should be used for the destination */ public static boolean shouldUpRecreateTask(Activity sourceActivity, Intent targetIntent) { String action = sourceActivity.getIntent().getAction(); return action != null && !action.equals(Intent.ACTION_MAIN); } /** * Convenience method that is equivalent to calling * <code>{@link #navigateUpTo(Activity, Intent) navigateUpTo}(sourceActivity, * {@link #getParentActivityIntent(Activity) getParentActivityIntent} (sourceActivity))</code>. * sourceActivity will be finished by this call. * * <p><em>Note:</em> This method should only be used when sourceActivity and the corresponding * parent are within the same task. If up navigation should cross tasks in some cases, see * {@link #shouldUpRecreateTask(Activity, Intent)}.</p> * * @param sourceActivity The current activity from which the user is attempting to navigate up */ public static void navigateUpFromSameTask(Activity sourceActivity) { Intent upIntent = getParentActivityIntent(sourceActivity); if (upIntent == null) { throw new IllegalArgumentException("Activity " + sourceActivity.getClass().getSimpleName() + " does not have a parent activity name specified." + " (Did you forget to add the android.support.PARENT_ACTIVITY <meta-data> " + " element in your manifest?)"); } navigateUpTo(sourceActivity, upIntent); } /** * Navigate from sourceActivity to the activity specified by upIntent, finishing sourceActivity * in the process. upIntent will have the flag {@link Intent#FLAG_ACTIVITY_CLEAR_TOP} set * by this method, along with any others required for proper up navigation as outlined * in the Android Design Guide. * * <p>This method should be used when performing up navigation from within the same task * as the destination. If up navigation should cross tasks in some cases, see * {@link #shouldUpRecreateTask(Activity, Intent)}.</p> * * @param sourceActivity The current activity from which the user is attempting to navigate up * @param upIntent An intent representing the target destination for up navigation */ public static void navigateUpTo(Activity sourceActivity, Intent upIntent) { upIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); sourceActivity.startActivity(upIntent); sourceActivity.finish(); } /** * Obtain an {@link Intent} that will launch {@link Intent#ACTION_MAIN} with an explicit * target activity specified by sourceActivity's {@link #PARENT_ACTIVITY} <meta-data> * element in the application's manifest. * * @param sourceActivity Activity to fetch a parent intent for * @return a new Intent targeting the defined parent activity of sourceActivity */ public static Intent getParentActivityIntent(Activity sourceActivity) { String parentActivity = getParentActivityName(sourceActivity); if (parentActivity == null) return null; return new Intent(Intent.ACTION_MAIN).setClassName(sourceActivity, parentActivity); } /** * Obtain an {@link Intent} that will launch {@link Intent#ACTION_MAIN} with an explicit * target activity specified by sourceActivityClass's {@link #PARENT_ACTIVITY} <meta-data> * element in the application's manifest. * * @param context Context for looking up the activity component for sourceActivityClass * @param sourceActivityClass {@link java.lang.Class} object for an Activity class * @return a new Intent targeting the defined parent activity of sourceActivity * @throws NameNotFoundException if the ComponentName for sourceActivityClass is invalid */ public static Intent getParentActivityIntent(Context context, Class<?> sourceActivityClass) throws NameNotFoundException { String parentActivity = getParentActivityName(context, new ComponentName(context, sourceActivityClass)); if (parentActivity == null) return null; return new Intent(Intent.ACTION_MAIN).setClassName(context, parentActivity); } /** * Obtain an {@link Intent} that will launch {@link Intent#ACTION_MAIN} with an explicit * target activity specified by sourceActivityClass's {@link #PARENT_ACTIVITY} <meta-data> * element in the application's manifest. * * @param context Context for looking up the activity component for the source activity * @param componentName ComponentName for the source Activity * @return a new Intent targeting the defined parent activity of sourceActivity * @throws NameNotFoundException if the ComponentName for sourceActivityClass is invalid */ public static Intent getParentActivityIntent(Context context, ComponentName componentName) throws NameNotFoundException { String parentActivity = getParentActivityName(context, componentName); if (parentActivity == null) return null; if (parentActivity.charAt(0) == '.') { parentActivity = context.getPackageName() + parentActivity; } return new Intent(Intent.ACTION_MAIN).setClassName(context, parentActivity); } /** * Return the fully qualified class name of sourceActivity's parent activity as specified by * a {@link #PARENT_ACTIVITY} <meta-data> element within the activity element in * the application's manifest. * * @param sourceActivity Activity to fetch a parent class name for * @return The fully qualified class name of sourceActivity's parent activity or null if * it was not specified */ public static String getParentActivityName(Activity sourceActivity) { try { return getParentActivityName(sourceActivity, sourceActivity.getComponentName()); } catch (NameNotFoundException e) { // Component name of supplied activity does not exist...? throw new IllegalArgumentException(e); } } /** * Return the fully qualified class name of a source activity's parent activity as specified by * a {@link #PARENT_ACTIVITY} <meta-data> element within the activity element in * the application's manifest. The source activity is provided by componentName. * * @param context Context for looking up the activity component for the source activity * @param componentName ComponentName for the source Activity * @return The fully qualified class name of sourceActivity's parent activity or null if * it was not specified */ public static String getParentActivityName(Context context, ComponentName componentName) throws NameNotFoundException { PackageManager pm = context.getPackageManager(); ActivityInfo info = pm.getActivityInfo(componentName, PackageManager.GET_META_DATA); if (info.metaData == null) return null; String parentActivity = info.metaData.getString(PARENT_ACTIVITY); if (parentActivity == null) return null; if (parentActivity.charAt(0) == '.') { parentActivity = context.getPackageName() + parentActivity; } return parentActivity; } /** No instances! */ private NavUtils() { } }