Isaac Waller Isaac Waller - 1 month ago 33
Android Question

Android - Get time of chronometer widget

I have a Chronometer widget in my Android app. I was wondering how to get the time from it. I tried getText, getFormat, getBase, etc, but none of them work. This is probably a easy question, but I could not find it on Google.

Thanks, Isaac Waller

Example code snippet:

Chronometer t = (Chronometer)findViewById(R.id.toptime);
long time = SystemClock.elapsedRealtime()-t.getBase();
Log.d(null,"Was: "+time); //time is not the proper time for some reason - it is a random number between 0 and 50
t.setBase(SystemClock.elapsedRealtime());
t.start();

Answer

If you look at the source of the Chronometer class, you'll see that it doesn't store the elapsed time in a field and it calculates it internally every time it needs to update the display.

However it's relatively easy to do the same in your own code:

long elapsedMillis = SystemClock.elapsedRealtime() - chronometerInstance.getBase();

This assumes that you have started your clock something like this:

chronometerInstance.setBase(SystemClock.elapsedRealtime());
chronometerInstance.start();

Here's a full example:

public class ChronoExample extends Activity {
Chronometer mChronometer;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    LinearLayout layout = new LinearLayout(this);
    layout.setOrientation(LinearLayout.VERTICAL);

    mChronometer = new Chronometer(this);
    layout.addView(mChronometer);

    Button startButton = new Button(this);
    startButton.setText("Start");
    startButton.setOnClickListener(mStartListener);
    layout.addView(startButton);

    Button stopButton = new Button(this);
    stopButton.setText("Stop");
    stopButton.setOnClickListener(mStopListener);
    layout.addView(stopButton);

    Button resetButton = new Button(this);
    resetButton.setText("Reset");
    resetButton.setOnClickListener(mResetListener);
    layout.addView(resetButton);        

    setContentView(layout);
}

private void showElapsedTime() {
    long elapsedMillis = SystemClock.elapsedRealtime() - mChronometer.getBase();            
    Toast.makeText(ChronoExample.this, "Elapsed milliseconds: " + elapsedMillis, 
            Toast.LENGTH_SHORT).show();
}

View.OnClickListener mStartListener = new OnClickListener() {
    public void onClick(View v) {
        mChronometer.start();
        showElapsedTime();
    }
};

View.OnClickListener mStopListener = new OnClickListener() {
    public void onClick(View v) {
        mChronometer.stop();
        showElapsedTime();
    }
};

View.OnClickListener mResetListener = new OnClickListener() {
    public void onClick(View v) {
        mChronometer.setBase(SystemClock.elapsedRealtime());
        showElapsedTime();
    }
};
}

One somewhat confusing thing about Chronometer is that you can't really use it as a stopwatch that gets started, stopped and restarted again. When it's running, it will always show the time elapsed since you last reset it, no matter how many times and for how long you have stopped it in the meantime. When it is stopped, it simply stops updating the display.

If you need something like a stopwatch you'll have to subclass Chronometer or maybe create your own version using the source.

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