Equivalent to javax.swing.Timer in Android

问题:

Is there something that looks like the javax.swing.Timer on Android. I know how to create own Threads, but is there something that is like the swing-timer?

回答1:

There is also Java's TimerTask. Here's an example from my code where I'm playing audio samples:

import java.util.Timer;
import java.util.TimerTask;

// from constructor, shown here out of place
timer = new Timer();

// and in method, again, shown out of place:
        INTERVAL_MILLISECONDS = (int)((double)(bufSize) / (double)(nativeSampleRate * 2) * 1000);
        timer.scheduleAtFixedRate( new TimerTask() {
                public void run() {
                        synchronized(this){
                                track.write(data, 0, bufSize);
                                track.play();
                        }
                }
        }, 0, INTERVAL_MILLISECONDS);

回答2:

You are probably looking for the class android.os.CountDownTimer

You can inherit the class like this:

class MyTimer extends CountDownTimer
{
    public MyTimer(int secsInFuture) {
        super(secsInFuture*1000, 1000); //interval/ticks each second.
    }

    @Override
    public void onFinish() {
        Log.d("mytag","timer finished!");
    }

    @Override
    public void onTick(long millisUntilFinished) {
        //fired on each interval
        Log.d("mytag","tick; " + millisUntilFinished + " ms left");
    }
}

回答3:

The main point of javax.swing.Timer is that it executes tasks on GUI thread (EDT - event dispatching thread). This makes it safe to manipulate Swing components.

In Android there is also EDT and you should only manipulate GUI elements on EDT. To delay your code and then run it on EDT use view.postDelayed(runnable).