Question

我在Handler中创建AlertDialog时遇到问题，因为它会导致内存泄漏或其他错误。

详细信息：

我有一个活动，线程和处理程序，其中包含对活动的WeakReference。在开始我的线程之前，我在我的activity类中创建了ProgressDialog dialog。线程任务具有对MyHandler对象的引用。当用户在我的活动中解除dialog时，onCancelListener会调用线程的中断（）。我的线程安全地完成任务并将Message DOWNLOAD_STATE.CANCELLED发送到主活动线程。然后我用MyHandler

中的代码创建AlertDialog

问题：

问题是用户在解除alert（取消线程）之后和创建新AlertDialog之前立即按下后退按钮（在MyHandler类内）。花了大约一秒钟。当用户在这段时间没有按回时，一切正常。

它在这里泄漏（在MyHandler类中）： new AlertDialog.Builder(activity).setMessage("update cancelled").setPositiveButton("OK", null).show();

正常情况是当用户按下后退按钮时，活动被破坏（活动onBackKeyPressed的效果），但为什么handleMessage没有停止并创建AlertDialog？

我的处理程序类：

static class MyHandler extends Handler {

    WeakReference<MainActivity> activityRef;
    MyHandler(MainActivity activity)
    {
        this.activityRef=new WeakReference<MainActivity>(activity);
    }

    @Override
    public void handleMessage(Message msg) {

        MainActivity activity=activityRef.get();
        if(activity==null)
            return;

        if (msg.arg1==DownloadTask.DOWNLOAD_STATE.FINISHED.ordinal())
        {
            activity.dialog.dismiss();
            Toast.makeText(activity, "updated", Toast.LENGTH_LONG).show();
        }

        else if( msg.arg1== DownloadTask.DOWNLOAD_STATE.CANCELLED.ordinal())
        {
            new AlertDialog.Builder(activity).setMessage("update cancelled").setPositiveButton("OK", null).show();
        }

        else if(msg.arg1==DownloadTask.DOWNLOAD_STATE.ERROR.ordinal())
        {

              activity.dialog.dismiss();
            new AlertDialog.Builder(activity).setMessage(activity.getString(R.string.no_connection_info)).setPositiveButton("OK", null).show();
        }

    }
}

内部线程的可运行：

if(Thread.interrupted()) 
        {
            Message msg=handler.obtainMessage();
            msg.arg1=DOWNLOAD_STATE.CANCELLED.ordinal();
            msg.arg2=counter;
            msg.obj=cities.length;
            handler.sendMessage(msg);

            return;
        }

错误堆栈trace1：

android.view.WindowLeaked: Activity com.mycompany.mooz.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@42723848 that was originally added here
        at android.view.ViewRootImpl.<init>(ViewRootImpl.java:403)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:311)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
        at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
        at android.view.Window$LocalWindowManager.addView(Window.java:554)
        at android.app.Dialog.show(Dialog.java:277)
        at android.support.v7.app.AlertDialog$Builder.show(AlertDialog.java:902)
        at com.mycompany.mooz.MainActivity$MyHandler.handleMessage(MainActivity.java:55)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:4921)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
        at dalvik.system.NativeStart.main(Native Method)

错误堆栈跟踪2：

android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@427329e0 is not valid; is your activity running?
        at android.view.ViewRootImpl.setView(ViewRootImpl.java:700)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:345)
        at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
        at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
        at android.view.Window$LocalWindowManager.addView(Window.java:554)
        at android.app.Dialog.show(Dialog.java:277)
        at android.support.v7.app.AlertDialog$Builder.show(AlertDialog.java:902)
        at com.mycompany.mooz.MainActivity`enter code here`$MyHandler.handleMessage(MainActivity.java:55)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:4921)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:511)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
        at dalvik.system.NativeStart.main(Native Method)

Answer 1

活动com.mycompany.mooz.MainActivity已泄露窗口 com.android.internal.policy.impl.PhoneWindow$DecorView@42723848那个最初是在这里添加的

通常在Activity暂停且对话框仍在屏幕上时发生。保留对Dialog的引用，如果引用不为null，则在onPause中调用dismiss并且对话框为isShowing

  if (mDialog != null && mDialog.isShowing()) {
        mDialog.dismiss();
  }

android.view.WindowManager $ BadTokenException：无法添加窗口 - 令牌android.os.BinderProxy@427329e0无效;是你的活动运行

当您尝试在暂停活动时显示对话框时，通常会发生这种情况。避免检查isFinishing标志

  if (activity != null && !activity.isFinishing()) {
      // show dialog
  }

尽管使用了WeakReference

详细信息：

问题：

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