Is there already a StopWatch class for android and why doesn't my implementation work?
Have a look at the Chronometer class.
Sample code from APIDemo:
import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Chronometer;
public class ChronometerDemo extends Activity {
Chronometer mChronometer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.chronometer);
Button button;
mChronometer = (Chronometer) findViewById(R.id.chronometer);
// Watch for button clicks.
button = (Button) findViewById(R.id.start);
button.setOnClickListener(mStartListener);
button = (Button) findViewById(R.id.stop);
button.setOnClickListener(mStopListener);
button = (Button) findViewById(R.id.reset);
button.setOnClickListener(mResetListener);
button = (Button) findViewById(R.id.set_format);
button.setOnClickListener(mSetFormatListener);
button = (Button) findViewById(R.id.clear_format);
button.setOnClickListener(mClearFormatListener);
}
View.OnClickListener mStartListener = new OnClickListener() {
public void onClick(View v) {
mChronometer.start();
}
};
View.OnClickListener mStopListener = new OnClickListener() {
public void onClick(View v) {
mChronometer.stop();
}
};
View.OnClickListener mResetListener = new OnClickListener() {
public void onClick(View v) {
mChronometer.setBase(SystemClock.elapsedRealtime());
}
};
View.OnClickListener mSetFormatListener = new OnClickListener() {
public void onClick(View v) {
mChronometer.setFormat("Formatted time (%s)");
}
};
View.OnClickListener mClearFormatListener = new OnClickListener() {
public void onClick(View v) {
mChronometer.setFormat(null);
}
};
}
R.layout.chronometer:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:padding="4dip"
android:gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Chronometer android:id="@+id/chronometer"
android:format="@string/chronometer_initial_format"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0"
android:paddingBottom="30dip"
android:paddingTop="30dip"
/>
<Button android:id="@+id/start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/chronometer_start">
<requestFocus />
</Button>
<Button android:id="@+id/stop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/chronometer_stop">
</Button>
<Button android:id="@+id/reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/chronometer_reset">
</Button>
<Button android:id="@+id/set_format"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/chronometer_set_format">
</Button>
<Button android:id="@+id/clear_format"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/chronometer_clear_format">
</Button>
</LinearLayout>
Add this to Strings.xml
<string name="chronometer_start">Start</string>
<string name="chronometer_stop">Stop</string>
<string name="chronometer_reset">Reset</string>
<string name="chronometer_set_format">Set format string</string>
<string name="chronometer_clear_format">Clear format string</string>
<string name="chronometer_initial_format">Initial format: <xliff:g id="initial-format">%s</xliff:g></string>
You should use a Chronometer.
But anyway, your code can work if you remove the sleep from UI thread.
private final Runnable mRunnable = new Runnable() {
@Override
public void run() {
if (mStarted) {
long seconds = (System.currentTimeMillis() - t) / 1000;
statusBar.setText(String.format("%02d:%02d", seconds / 60, seconds % 60));
handler.postDelayed(runnable, 1000L);
}
}
};
private Hanlder mHandler;
private boolean mStarted;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mHandler = new Handler();
}
@Override
protected void onStart() {
super.onStart();
mStarted = true;
mHandler.postDealyed(runnable, 1000L);
}
@Override
protected void onStop() {
super.onStop();
mStarted = false;
mHandler.removeCallbacks(mRunnable);
}
You should use a Chronometer.
Chronometer mChronometer;
mChronometer = (Chronometer) findViewById(R.id.chronometer1);
long timeWhenStopped = 0;
when we stop the chronometer
timeWhenStopped = mChronometer.getBase() - SystemClock.elapsedRealtime();
mChronometer.stop();
the chronometer before starting it
mChronometer.setBase(SystemClock.elapsedRealtime() + timeWhenStopped);
mChronometer.start();
resetting the chronometer
mChronometer.setBase(SystemClock.elapsedRealtime());
timeWhenStopped = 0;