Question

我正在开发一个应用程序，我想在其中实现计时器任务，每5秒打一次Toast消息。问题是我的应用程序在运行它5秒后崩溃.Below是我的代码的一部分，请告诉我我在哪里犯错误，如何克服它。

public class main_activity extends Activity implements BluetoothLeUart.Callback{

public ImageButton fabbutton;
Activity activity;
Timer time;
TimerTask timetask;
Handler handle;

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

    fabbutton = (ImageButton) findViewById(R.id.fabbutton);

  startTimer(); //this is where I start my timer task  

  fabbutton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            scanLeDevice(false);
            Intent intent = new Intent(getApplicationContext(), ScanList.class);
            startActivity(intent);

        }

    });
 } 
 public void startTimer(){
    time = new Timer();
    initializeTimerTask();
    time.schedule(timetask, 5000, 10000);

}
public void initializeTimerTask(){
    timetask = new TimerTask() {
        @Override
        public void run() {
            handle.post(new Runnable() {
                @Override
                public void run() {
                    int duration = Toast.LENGTH_SHORT;
                    Toast toast = Toast.makeText(getApplicationContext(),"Timer...", duration);
                    toast.show();

                }
            });
        }
    };
}
public void stoptimertask() {
    //stop the timer, if it's not already null
    if (time != null) {
        time.cancel();
        time = null;

    }

   }
 }

Answer 1

你忘了初始化处理程序，只需在oncreate或startTimer();

中添加以下行

handle = new Handler();

甚至在您的情况下，您可以使用，

runOnUiThread(new Runnable(){
            @Override
            public void run() {
                int duration = Toast.LENGTH_SHORT;
                Toast toast = Toast.makeText(getApplicationContext(),"Timer...", duration);
                toast.show();

            }
        });

实现Timer Task会使应用程序崩溃

1 个答案: