安卓:你的活动在运行吗？对话框无法在OnFinish上显示

Question

我有一个名为SpotOnView的视图，正在Game_shooting_AB上扩展。编码如下。

背景：

在SpotOnView中有一个倒计时器。当时间到了，游戏就结束了，会弹出一个对话框来询问用户是想退出还是再玩一次。

SpotOnView代码：

public class SpotOnView extends View 
{
   ......
  // constructs a new SpotOnView
   public SpotOnView(Context context, RelativeLayout parentLayout)
   {
      super(context);          
      resources = context.getResources();            
      layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
      ....    

   } 


   public void start_timer() 
   {
        if (!timerHasStarted) 
        {
            countDownTimer.start();
            timerHasStarted = true;
        } 
        else 
        {
            countDownTimer.cancel();
            timerHasStarted = false;
        }
   }

    public class MyCountDownTimer extends CountDownTimer 
    {
        public MyCountDownTimer(long startTime, long interval) 
        {
            super(startTime, interval);
        }

        @Override
        public void onFinish() 
        {
            text.setText("Time's up!");
               ((Game_shooting_AB)getContext()).replay_dialog();  //LINE 181
        }

        @Override
        public void onTick(long millisUntilFinished) 
        {
            ....
        }
    }

Game_shooting_AB代码：

   public void onCreate(Bundle savedInstanceState) 
   {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.game_shooting);

      // create a new SpotOnView and add it to the RelativeLayout
      RelativeLayout layout = (RelativeLayout) findViewById(R.id.relativeLayout);
      view = new SpotOnView(this, layout);                                          //EXTENDING HERE
      layout.addView(view, 0); // add view to the layout
    ....
}



public void replay_dialog()    
{
    final Dialog dialog1 = new Dialog(Game_shooting_AB.this, android.R.style.Theme_Translucent_NoTitleBar);
    WindowManager.LayoutParams lp = dialog1.getWindow().getAttributes();
    lp.dimAmount = 0.7f;
    dialog1.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);

    Window window = dialog1.getWindow();
    window.setGravity(Gravity.CENTER);

    dialog1.setContentView(R.layout.alert_dialog_replay_shooting);
    dialog1.setCancelable(false);
    dialog1.show();     //LINE 431
    ....

逻辑猫：

在上述代码中添加了必要的行号作为注释。

11-22 00:16:34.365: W/dalvikvm(1105): threadid=1: thread exiting with uncaught exception (group=0x41f342a0)
11-22 00:16:34.370: E/AndroidRuntime(1105): FATAL EXCEPTION: main
11-22 00:16:34.370: E/AndroidRuntime(1105): android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@43304558 is not valid; is your activity running?
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.view.ViewRootImpl.setView(ViewRootImpl.java:708)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:346)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.view.Window$LocalWindowManager.addView(Window.java:554)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.app.Dialog.show(Dialog.java:277)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at com.app.abc.Game_shooting_AB.replay_dialog(Game_shooting_AB.java:431)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at com.app.abc.SpotOnView$MyCountDownTimer.onFinish(SpotOnView.java:181)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.os.CountDownTimer$1.handleMessage(CountDownTimer.java:118)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.os.Looper.loop(Looper.java:137)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at android.app.ActivityThread.main(ActivityThread.java:4898)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at java.lang.reflect.Method.invokeNative(Native Method)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at java.lang.reflect.Method.invoke(Method.java:511)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
11-22 00:16:34.370: E/AndroidRuntime(1105):     at dalvik.system.NativeStart.main(Native Method)

问题：

logcat显示您的活动正在运行吗？

1. 我知道对话需要有一个基础才能显示出来。但是如何修改代码呢？
2. 是否可以在SpotOnView中编码和显示对话框，而不是在Game_shooting_AB代码中编写？
3. 我试图通过将类MyCountDownTimer和方法replay_dialog移回Game_shooting_AB来修改代码，但同样的错误仍然出现。我想问一下，OnFinish of MyCountDownTimer是否会使活动完成，这样对话框就无法找到要显示的基础？

太感谢了！！

Answer 1

问题是从"((Game_shooting_AB)getContext()).replay_dialog();“开始的--这一行代码。

当您从视图内部调用getContext()时，您将从android的文档中找到“视图的上下文”。现在您要做的是将该上下文转换为Game_shooting_AB，这并不好，因为这可能是活动的上下文，也可能不是活动的上下文。请看Romain Guy's answer关于这一点。因此，android告诉你“你的活动在运行吗？”

现在，要解决当前的问题，可以通过任何公共方法将活动实例传递给此视图，并将其存储在局部变量中。

按照以下方式调整代码：

public class SpotOnView extends View 
{
  Game_shooting_AB mGame_shooting_AB;
  public void setGame_shooting_AB(Game_shooting_AB mGame_shooting_AB){
   this.mGame_shooting_AB = mGame_shooting_AB;
  }
   ......
   // constructs a new SpotOnView
  public SpotOnView(Context context, RelativeLayout parentLayout)
  {
   super(context);          
   resources = context.getResources();            
    layoutInflater = (LayoutInflater)          context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  ....    

  } 


  public void start_timer() 
  {
    if (!timerHasStarted) 
    {
        countDownTimer.start();
        timerHasStarted = true;
    } 
    else 
    {
        countDownTimer.cancel();
        timerHasStarted = false;
    }
  }

public class MyCountDownTimer extends CountDownTimer 
{
    public MyCountDownTimer(long startTime, long interval) 
    {
        super(startTime, interval);
    }

    @Override
    public void onFinish() 
    {
        text.setText("Time's up!");
           mGame_shooting_AB.replay_dialog();  //LINE 181
    }

    @Override
    public void onTick(long millisUntilFinished) 
    {
        ....
    }
}

在获得SpotOnView实例之后，设置活动：

      view = new SpotOnView(this, layout);                                          //EXTENDING HERE
  layout.addView(view, 0); // add view to the layout
  view.setGame_shooting_AB(Game_shooting_AB.this);

希望这能有所帮助。