【Launcher小知识点】home按键监听

监听广播

在我们每次点击Home按键时系统会发出action为Intent.ACTION_CLOSE_SYSTEM_DIALOGS的广播，用于关闭系统Dialog，此广播可以来监听Home按键。而我们的Launcher也是这样做的。在Launcher的onCreate中：

private class CloseSystemDialogsIntentReceiver extends BroadcastReceiver {         @Override         public void onReceive(Context context, Intent intent) {             closeSystemDialogs();             Log.i("Launcher","closeSystemDialogs");         }     }

onUserLeaveHint方法

/**      * 此方法当用户点击home键或者menu键离开launcher应用时调用      */     protected void onUserLeaveHint() {         super.onUserLeaveHint();         sPausedFromUserAction = true;         Log.i(TAG,"onUserLeaveHint");     }

导航栏home按键触发intent

 mHomeIntent =  new Intent(Intent.ACTION_MAIN, null);         mHomeIntent.addCategory(Intent.CATEGORY_HOME);         mHomeIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK                 | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);

@Override     protected void onNewIntent(Intent intent) {         Log.i("Launcher","onNewIntent");         long startTime = 0;         if (DEBUG_RESUME_TIME) {             startTime = System.currentTimeMillis();         }         super.onNewIntent(intent);          // Close the menu         if (Intent.ACTION_MAIN.equals(intent.getAction())) {             // also will cancel mWaitingForResult.             closeSystemDialogs();              final boolean alreadyOnHome =                     ((intent.getFlags() & Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT)                         != Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);              Runnable processIntent = new Runnable() {                 public void run() {                     if (mWorkspace == null) {                         // Can be cases where mWorkspace is null, this prevents a NPE                         return;                     }                     Folder openFolder = mWorkspace.getOpenFolder();                     // In all these cases, only animate if we're already on home                     mWorkspace.exitWidgetResizeMode();                     if (alreadyOnHome && mState == State.WORKSPACE && !mWorkspace.isTouchActive() &&                             openFolder == null) {                         mWorkspace.moveToDefaultScreen(true);                     }                      closeFolder();                     exitSpringLoadedDragMode();                      // If we are already on home, then just animate back to the workspace,                     // otherwise, just wait until onResume to set the state back to Workspace                     if (alreadyOnHome) {                         showWorkspace(true);                     } else {                         mOnResumeState = State.WORKSPACE;                     }                      final View v = getWindow().peekDecorView();                     if (v != null && v.getWindowToken() != null) {                         InputMethodManager imm = (InputMethodManager)getSystemService(                                 INPUT_METHOD_SERVICE);                         imm.hideSoftInputFromWindow(v.getWindowToken(), 0);                     }                      // Reset AllApps to its initial state                     if (!alreadyOnHome && mAppsCustomizeTabHost != null) {                         mAppsCustomizeTabHost.reset();                     }                 }             };              if (alreadyOnHome && !mWorkspace.hasWindowFocus()) {                 // Delay processing of the intent to allow the status bar animation to finish                 // first in order to avoid janky animations.                 mWorkspace.postDelayed(processIntent, 350);             } else {                 // Process the intent immediately.                 processIntent.run();             }          }         if (DEBUG_RESUME_TIME) {             Log.d(TAG, "Time spent in onNewIntent: " + (System.currentTimeMillis() - startTime));         }     }

文章来源: 【Launcher小知识点】home按键监听