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Asked: 2026-06-09T00:08:56+00:00

I have a simple program with one TextView and two Buttons: Button1 and Button2.

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I have a simple program with one TextView and two Buttons: Button1 and Button2.

Clicking on Button 1 will start a counter, increasing by 1 every 1 second and show result on TextView; clinking on Button 2 will stop it. Here is a part of my code for Button1. But it does not work.

    Timer T=new Timer();
    T.scheduleAtFixedRate(new TimerTask() {         
            @Override
            public void run() {
                myTextView.setText("count="+count);
                count++;                
            }
        }, 1000, 1000);

I know that there are some similar questions about this using Thread but it seems like they do not mention about stopping the counter.

Any suggestion is really appreciated.

Added:

Hello, I just shortened my code just to this from a much bigger program, but it is still crashed:

package com.example.hello;
import java.util.Timer;
import java.util.TimerTask;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;
public class MainActivity extends Activity {
    TextView myTextView;
    int count=0;
    Timer T;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myTextView=(TextView)findViewById(R.id.t);
        T=new Timer();
        T.scheduleAtFixedRate(new TimerTask() {         
            @Override
            public void run() {
                myTextView.setText("count="+count);
                count++;                
            }
        }, 1000, 1000);       
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
    
}

The log file (I do not want to post this because it is too long but someone requested it):

07-28 17:35:07.012: W/dalvikvm(11331): threadid=7: thread exiting with uncaught exception (group=0x4001d800)
07-28 17:35:07.016: E/AndroidRuntime(11331): FATAL EXCEPTION: Timer-0
07-28 17:35:07.016: E/AndroidRuntime(11331): android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.ViewRoot.checkThread(ViewRoot.java:2802)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.ViewRoot.requestLayout(ViewRoot.java:594)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.View.requestLayout(View.java:8125)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.View.requestLayout(View.java:8125)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.View.requestLayout(View.java:8125)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.View.requestLayout(View.java:8125)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:254)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.view.View.requestLayout(View.java:8125)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.widget.TextView.checkForRelayout(TextView.java:5378)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.widget.TextView.setText(TextView.java:2688)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.widget.TextView.setText(TextView.java:2556)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at android.widget.TextView.setText(TextView.java:2531)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at com.example.hello.MainActivity$1.run(MainActivity.java:21)
07-28 17:35:07.016: E/AndroidRuntime(11331):    at java.util.Timer$TimerImpl.run(Timer.java:289)
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1 Answer

  1. Editorial Team

    You can introduce flag. Something like isPaused. Trigger this flag whenever ‘Pause’ button pressed. Check flag value in your timer task. Success.

    Timer T=new Timer();
T.scheduleAtFixedRate(new TimerTask() {         
        @Override
        public void run() {
            runOnUiThread(new Runnable()
            {
                @Override
                public void run()
                {
                    myTextView.setText("count="+count);
                    count++;                
                }
            });
        }
    }, 1000, 1000);


 onClick(View v)
 {
      //this is 'Pause' button click listener
      T.cancel();
 }
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