开始另一个活动时如何停止可运行对象？

Question

I have a Android app that shows a dialog when a value is '1' and shows the dialog repeatedly till the value is set to '0'. A Runnable calls a Handler which starts the dialog, and the Runnable loops with a delay.

Problem is that when I go to another activity with the same function and go back, the dialog is already open. This causes my app to crash. I already try to use removeMessage and removeCallback but still have the problem.

Handler

Handler myHandler = new Handler()
{
    @Override
    public void handleMessage(Message msg)
    {
        /* Dialog */
        final AlertDialog.Builder AlertAlarm_Build;
        LayoutInflater inflater = (LayoutInflater) Settings_Activity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        AlertAlarm_Build = new AlertDialog.Builder(Settings_Activity.this);
        final View Disengaged_View;
        Disengaged_View = inflater.inflate(R.layout.disengage_dialog,null);
        final AlertDialog PasswordDialog = AlertAlarm_Build.create();
        PasswordDialog.show();

        final String[] given_password = new String[1];
        final boolean[] Password_Pass = {false};

        //respose
        final RequestQueue requestHander;
        requestHander = (RequestQueue) Volley.newRequestQueue(getApplicationContext());

...//Ask for password

        //New
        PasswordDialog.setOnDismissListener(new DialogInterface.OnDismissListener()
        {
            @Override
            public void onDismiss(DialogInterface dialogInterface)
            {
                recreate();
            }
        });

    }

};

Runnable

    //Runnable
final Runnable aMyRunnable = new Runnable()
{
    @Override
    public void run()
    {
        RequestQueue requestRun;
        requestRun = (RequestQueue) Volley.newRequestQueue(getApplicationContext());

        if(New_engaged[0].equals("1") && New_alarm[0].equals("1"))
        {
            set_engaged[0] = "1";
            myHandler.sendEmptyMessage(0);
        }
        else
        {
            requestRun.add(JOR_SystemCheck);
            myHandler.postDelayed(this,5000);

        }
    }
};

onStop

    protected void onStop() {
        super.onStop();
        myHandler.removeCallbacksAndMessages(aMyRunnable);
        myHandler.removeMessages(0);
    }

Error

/AndroidRuntime: FATAL EXCEPTION: main
              Process: com.example.djwiz.eclipse5, PID: 17705
              android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@f8866f3 is not valid; is your activity running?
                  at android.view.ViewRootImpl.setView(ViewRootImpl.java:765)
                  at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:356)
                  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:92)
                  at android.app.Dialog.show(Dialog.java:330)
                  at com.example.djwiz.eclipse5.Settings_Activity$1.handleMessage(Settings_Activity.java:68)
                  at android.os.Handler.dispatchMessage(Handler.java:105)
                  at android.os.Looper.loop(Looper.java:164)
                  at android.app.ActivityThread.main(ActivityThread.java:6541)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Answer 1

Based on the documentation for removeCallbacksAndMessages

Remove any pending posts of callbacks and sent messages whose obj is token . If token is null, all callbacks and messages will be removed

Your code won't match any token: myHandler.removeCallbacksAndMessages(aMyRunnable);

So the solution would be to use:

myHandler.removeCallbacksAndMessages(null);