TestTimer.java

package cn.yo2.aquarium.android.testtimer;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class TestTimer extends Activity {
	private Button btnStart;
	private Button btnStop;
	private Button btnReset;
	private TextView tvCounter;
	private long count = 0;
	private boolean run = false;

	private Handler handler = new Handler();

	private Runnable task = new Runnable() {

		public void run() {
			// TODO Auto-generated method stub
			if (run) {
				handler.postDelayed(this, 1000);
				count++;
			}
			tvCounter.setText("Count: " + count);
		}
	};

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		btnStart = (Button) findViewById(R.id.Button01);
		btnStop = (Button) findViewById(R.id.Button02);
		btnReset = (Button) findViewById(R.id.Button03);
		tvCounter = (TextView) findViewById(R.id.counter);

		btnStart.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {
				// TODO Auto-generated method stub
				run = true;
				updateButton();
				handler.postDelayed(task, 1000);
			}
		});

		btnStop.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {
				// TODO Auto-generated method stub
				run = false;
				updateButton();
				handler.post(task);
			}
		});

		btnReset.setOnClickListener(new OnClickListener() {

			public void onClick(View v) {
				// TODO Auto-generated method stub
				count = 0;
				run = false;
				updateButton();
				handler.post(task);
			}
		});
	}

	private void updateButton() {
		btnStart.setEnabled(!run);
		btnStop.setEnabled(run);
	}
}