Android App中連續點擊Back鍵退出應用

   現在的App就用越來越人性化了，為了滿足用戶的體驗欲望，從各個方面都進行了仔細處理。比如我們點擊第一次點擊Back鍵的時候，會溫馨提示“再按一次返回鍵退出應用”等，今天 就記錄下自己在項目中寫的這個小功能：

首先寫個工具類：

public class DoubleClickExitApp {

private Context mcontext;
   /是否是再次點擊back鍵*/
   private boolean isOnKeyBack;
   private Handler mHandler;
   /退出提示Toast*/
   private Toast mExitToast;
public DoubleClickExitApp(Context context) {
      this.mcontext = context;
      this.mHandler = new Handler(Looper.getMainLooper());
   }
/所在Activity中的點擊返回事件處理*/
   public boolean onKeyDown(int keyCode, KeyEvent event) {
      if(keyCode != KeyEvent.KEYCODE_BACK) {//如果不是點擊的返回鍵，則返回false
         return false;
      }
      if(isOnKeyBack) {
         mHandler.removeCallbacks(onBackExitRunnable);
         if(mExitToast != null){
            mExitToast.cancel();
         }
         /直接退出*/
         AppManager.getAppManager().AppExit(mcontext);
         return true;
      } else {
         isOnKeyBack = true;
         if(mExitToast == null) {
            mExitToast = Toast.makeText(mcontext, "再按一次返回鍵退出應用", Toast.LENGTH_SHORT);
         }
         mExitToast.show();
         mHandler.postDelayed(onBackExitRunnable, 2000);
         return true;
      }
   }
private Runnable onBackExitRunnable = new Runnable() {

  @Override
  public void run() {
     isOnKeyBack = false;
     if(mExitToast != null){
        mExitToast.cancel();
     }
  }

};
}</pre> 


然后在對應的Activity或是主頁面中直接調用：

public class MainActivity extends Activity{
     private DoubleClickExitApp mDoubleClickExitApp;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

     mDoubleClickExitApp = new DoubleClickExitApp(this);

}    @Override    protected void onDestroy() {        super.onDestroy();    }   /**在處理onKeyDown事件中調用我們寫的工具類方法就可以*/    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {        if (keyCode == KeyEvent.KEYCODE_BACK) {               return mDoubleClickExitApp.onKeyDown(keyCode, event);        }else{

      return super.onKeyDown(keyCode, event);

   }


}


</pre>