Chronometer 计时器使用

public class TestProject extends Activity {
    TextView textGoesHere;
    long startTime;
    long countUp;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Chronometer stopWatch = (Chronometer) findViewById(R.id.chrono);
        startTime = SystemClock.elapsedRealtime();

        textGoesHere = (TextView) findViewById(R.id.textGoesHere);
        stopWatch.setOnChronometerTickListener(new OnChronometerTickListener(){
            @Override
            public void onChronometerTick(Chronometer arg0) {
                countUp = (SystemClock.elapsedRealtime() - arg0.getBase()) / 1000;
                String asText = (countUp / 60) + ":" + (countUp % 60); 
                textGoesHere.setText(asText);
            }
        });
        stopWatch.start();
    }
}

<Chronometer android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/chrono"
    android:visibility="gone"/>