Android-每单位时间执行动作

Question

This is more of a question of ignorance than inability. I am trying to build a timer application, but have found the CountDownTimer object too inaccurate for my purposes. Thus, I want to manually create the timer by just ticking every unit of time and performing some kind of action on each tick (without necessarily counting down to anything, as I will handle this manually) - is there a built-in object to do this (other than CountDownTimer), or do I have to use threads/sleeps?

Answer 1

Use a Handler and the postDelayed() method. Accurate and easy to use. You just have to keep putting the callback in after every loop, but that's not too onerous, and lets you adjust the interval as you see fit.

Handler timeThing = new Handler();    
Runnable timedWorker = new Runnable {
    public void run(){
        // Do work
        timeThing.postDelayed(this, 10000); // do it again later
    }
};
timeThing.postDelayed(timedWorker, 10000);

Answer 2

Use AsyncTask and Thread.sleep() :

AsyncTask task=new AsyncTask<Void,Void,Void>() {
    @Override
    protected Void doInBackground(Void... params) {
        while (!isCancelled()) {
            try {
                Thread.sleep(1000);
                publishProgress();
            } catch (InterruptedException e) {
                break;
            }
        }
        return null;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        //do something here    
    }
};
//task.execute(); to start
//task.cancel(); to stop

Your onProgressUpdate() will be called every N seconds (1000 in this example).