Android中Home鍵的監(jiān)聽和攔截示例

更新時間：2017年02月14日 08:09:39 作者：雪舞飛影

本篇文章主要介紹了Android中Home鍵的監(jiān)聽和攔截示例，小編覺得挺不錯的，現(xiàn)在分享給大家，也給大家做個參考。一起跟隨小編過來看看吧

首先大家應該先了解一種情況，就是Android在應用中是無法攔截Home鍵的，今天我們帶大家看一下Home鍵的三種情況。

1、在應用中按下Home鍵的邏輯處理

當我們在應用中按下Home鍵時界面會啟動到桌面，我們在frameworks\base\policy\src\com\android\internal\policy\impl\PhoneWindowManager.Java類中可以看到其實現(xiàn)原理，其不外乎就是調(diào)用了以下代碼。

  Intent mHomeIntent;
  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);

  startActivity(mHomeIntent);

創(chuàng)建一個啟動到桌面的Intent。

2、在應用中監(jiān)聽Home鍵

在Android應用中如果想監(jiān)聽Home鍵可以使用廣播機制，這個在源碼中也有體現(xiàn)。

static public final String SYSTEM_DIALOG_REASON_KEY = "reason";
  static public final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions";
  static public final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
  static public final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";
  static public final String SYSTEM_DIALOG_REASON_ASSIST = "assist";

  @Override
  public void onReceive(Context arg0, Intent arg1) {
    String action = arg1.getAction();
    //按下Home鍵會發(fā)送ACTION_CLOSE_SYSTEM_DIALOGS的廣播
    if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {

      String reason = arg1.getStringExtra(SYSTEM_DIALOG_REASON_KEY);
      if (reason != null) {
        if (reason.equals(SYSTEM_DIALOG_REASON_HOME_KEY)) {
          // 短按home鍵
          Toast.makeText(arg0, "短按Home鍵", Toast.LENGTH_SHORT).show();
        } else if (reason.equals(SYSTEM_DIALOG_REASON_RECENT_APPS)) {
          // RECENT_APPS鍵
          Toast.makeText(arg0, "RECENT_APPS", Toast.LENGTH_SHORT).show();
        }
      }
    }
  }

這樣就可以監(jiān)聽Home的是否被按下。

3、在Frameworks層攔截Home鍵

在frameworks\base\policy\src\com\android\internal\policy\impl\PhoneWindowManager.java文件中我們首先看一下interceptKeyBeforeDispatching()方法。

public long interceptKeyBeforeDispatching(WindowState win, KeyEvent event, int policyFlags) {

  //......
  if (keyCode == KeyEvent.KEYCODE_HOME) {

    //......
    handleShortPressOnHome();
  }
}

//進入handleShortPressOnHome
private void handleShortPressOnHome() {
    // If there's a dream running then use home to escape the dream
    // but don't actually go home.
    if (mDreamManagerInternal != null && mDreamManagerInternal.isDreaming()) {
      mDreamManagerInternal.stopDream(false /*immediate*/);
      return;
    }

    // Go home!
    launchHomeFromHotKey();
  }

進入launchHomeFromHotKey方法。

static public final String SYSTEM_DIALOG_REASON_KEY = "reason";
  static public final String SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS = "globalactions";
  static public final String SYSTEM_DIALOG_REASON_RECENT_APPS = "recentapps";
  static public final String SYSTEM_DIALOG_REASON_HOME_KEY = "homekey";
  static public final String SYSTEM_DIALOG_REASON_ASSIST = "assist";

void launchHomeFromHotKey() {
    if (isKeyguardShowingAndNotOccluded()) {
      // don't launch home if keyguard showing
    } else if (!mHideLockScreen && mKeyguardDelegate.isInputRestricted()) {
      // when in keyguard restricted mode, must first verify unlock
      // before launching home
      mKeyguardDelegate.verifyUnlock(new OnKeyguardExitResult() {
        @Override
        public void onKeyguardExitResult(boolean success) {
          if (success) {
            try {
              ActivityManagerNative.getDefault().stopAppSwitches();
            } catch (RemoteException e) {
            }
            sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY);
            startDockOrHome();
          }
        }
      });
    } else {
      // no keyguard stuff to worry about, just launch home!
      try {
        ActivityManagerNative.getDefault().stopAppSwitches();
      } catch (RemoteException e) {
      }
      if (mRecentsVisible) {
        // Hide Recents and notify it to launch Home
        awakenDreams();
        sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY);
        hideRecentApps(false, true);
      } else {
        // Otherwise, just launch Home
        sendCloseSystemWindows(SYSTEM_DIALOG_REASON_HOME_KEY);
        //啟動Launcher界面
        startDockOrHome();
      }
    }
  }

以上方法可處理Home鍵的攔截操作，接下來我們進入startDockOrHome方法。

void startDockOrHome() {

    if (OptConfig.LC_RAM_SUPPORT) {
      try {
        ActivityManagerNative.getDefault().startHomePre();
      } catch (RemoteException re) {

      }
    }

    awakenDreams();

    Intent dock = createHomeDockIntent();
    if (dock != null) {
      try {
        startActivityAsUser(dock, UserHandle.CURRENT);
        return;
      } catch (ActivityNotFoundException e) {
      }
    }

    //intent的相關設置
    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);

    startActivityAsUser(mHomeIntent, UserHandle.CURRENT);
  }

好啦，這里就對Home鍵進行簡單的監(jiān)聽和攔截。

以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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