android developer官网例子threadSample.zip

/* * 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 com.example.android.threadsample; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.Build; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentManager.OnBackStackChangedListener; import android.support.v4.app.FragmentTransaction; import android.support.v4.content.LocalBroadcastManager; import android.util.Log; import android.view.View; import android.view.WindowManager; /** * This activity displays Picasa's current featured images. It uses a service running * a background thread to download Picasa's "featured image" RSS feed. * <p> * An IntentHandler is used to communicate between the active Fragment and this * activity. This pattern simulates some of the communication used between * activities, and allows this activity to make choices of how to manage the * fragments. */ public class DisplayActivity extends FragmentActivity implements OnBackStackChangedListener { // A handle to the main screen view View mMainView; // An instance of the status broadcast receiver DownloadStateReceiver mDownloadStateReceiver; // Tracks whether Fragments are displaying side-by-side boolean mSideBySide; // Tracks whether navigation should be hidden boolean mHideNavigation; // Tracks whether the app is in full-screen mode boolean mFullScreen; // Tracks the number of Fragments on the back stack int mPreviousStackCount; // Instantiates a new broadcast receiver for handling Fragment state private FragmentDisplayer mFragmentDisplayer = new FragmentDisplayer(); // Sets a tag to use in logging private static final String CLASS_TAG = "DisplayActivity"; /** * Sets full screen mode on the device, by setting parameters in the current * window and View * @param fullscreen */ public void setFullScreen(boolean fullscreen) { // If full screen is set, sets the fullscreen flag in the Window manager getWindow().setFlags( fullscreen ? WindowManager.LayoutParams.FLAG_FULLSCREEN : 0, WindowManager.LayoutParams.FLAG_FULLSCREEN); // Sets the global fullscreen flag to the current setting mFullScreen = fullscreen; // If the platform version is Android 3.0 (Honeycomb) or above if (Build.VERSION.SDK_INT >= 11) { // Sets the View to be "low profile". Status and navigation bar icons will be dimmed int flag = fullscreen ? View.SYSTEM_UI_FLAG_LOW_PROFILE : 0; // If the platform version is Android 4.0 (ICS) or above if (Build.VERSION.SDK_INT >= 14 && fullscreen) { // Hides all of the navigation icons flag |= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION; } // Applies the settings to the screen View mMainView.setSystemUiVisibility(flag); // If the user requests a full-screen view, hides the Action Bar. if ( fullscreen ) { this.getActionBar().hide(); } else { this.getActionBar().show(); } } } /* * A callback invoked when the task's back stack changes. This allows the app to * move to the previous state of the Fragment being displayed. * */ @Override public void onBackStackChanged() { // Gets the previous global stack count int previousStackCount = mPreviousStackCount; // Gets a FragmentManager instance FragmentManager localFragmentManager = getSupportFragmentManager(); // Sets the current back stack count int currentStackCount = localFragmentManager.getBackStackEntryCount(); // Re-sets the global stack count to be the current count mPreviousStackCount = currentStackCount; /* * If the current stack count is less than the previous, something was popped off the stack * probably because the user clicked Back. */ boolean popping = currentStackCount < previousStackCount; Log.d(CLASS_TAG, "backstackchanged: popping = " + popping); // When going backwards in the back stack, turns off full screen mode. if (popping) { setFullScreen(false); } } /* * This callback is invoked by the system when the Activity is being killed * It saves the full screen status, so it can be restored when the Activity is restored * */ @Override protected void onSaveInstanceState(Bundle outState) { outState.putBoolean(Constants.EXTENDED_FULLSCREEN, mFullScreen); super.onSaveInstanceState(outState); } /* * This callback is invoked when the Activity is first created. It sets up the Activity's * window and initializes the Fragments associated with the Activity */ @Override public void onCreate(Bundle stateBundle) { // Sets fullscreen-related flags for the display getWindow().setFlags( WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN | WindowManager.LayoutParams.FLAG_LAYOUT_INSET_DECOR, WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN | WindowManager.LayoutParams.FLAG_LAYOUT_INSET_DECOR); // Calls the super method (required) super.onCreate(stateBundle); // Inflates the main View, which will be the host View for the fragments mMainView = getLayoutInflater().inflate(R.layout.fragmenthost, null); // Sets the content view for the Activity setContentView(mMainView); /* * Creates an intent filter for DownloadStateReceiver that intercepts broadcast Intents */ // The filter's action is BROADCAST_ACTION IntentFilter statusIntentFilter = new IntentFilter( Constants.BROADCAST_ACTION); // Sets the filter's category to DEFAULT statusIntentFilter.addCategory(Intent.CATEGORY_DEFAULT); // Instantiates a new DownloadStateReceiver mDownloadStateReceiver = new DownloadStateReceiver(); // Registers the DownloadStateReceiver and its intent filters LocalBroadcastManager.getInstance(this).registerReceiver( mDownloadStateReceiver, statusIntentFilter); /* * Creates intent filters for the FragmentDisplayer */ // One filter is for the action ACTION_VIEW_IMAGE IntentFilter displayerIntentFilter = new IntentFilter( Constants.ACTION_VIEW_IMAGE); // Adds a data filter for the HTTP scheme displayerIntentFilter.addDataScheme("http"); // Registers the receiver LocalBroadcastManager.getInstance(this).registerReceiver( mFragmentDisplayer, displayerIntentFilter); // Creates a second filter for ACTION_ZOOM_IMAGE displayerI