Android: delay function execution and possibility to cancel its execution

Question

I have a animated loader in my application right now.

    public void startLoader() {
        Runnable task = new Runnable() {
             @Override
             public void run() {
                lock = true;
                loader.setVisibility(View.VISIBLE);
            }
        };
        runOnUiThread(task);
    }

    public void stopLoader() {
        Runnable task = new Runnable() {
             @Override
             public void run() {
                lock = false;
                loader.setVisibility(View.GONE);
            }
        };
        runOnUiThread(task);
    }

Now I want it to work like this:

stopLoader should have an delayed execution of like 1000ms, so it dissapears 1 second after stopLoader is called. but if the startLoader is called within that 1000ms the stopLoader timer would be cancelled.

What is the best way to implement this?

Answer 1

You should use Handler instead of runOnUiThread.
With handler you can cancel any delayed task using handler.removeCallbacks(runnable).

Handler mHandler = new Handler();
Runnable startTask = new Runnable() {
         @Override
         public void run() {
            lock = true;
            loader.setVisibility(View.VISIBLE);
        }
    };
Runnable stopTask = new Runnable() {
         @Override
         public void run() {
            lock = false;
            loader.setVisibility(View.GONE);
        }
    };
public void startLoader() {
   mHandler.removeCallbacks(stopTask);
   mHandler.post(startTask);
}

public void stopLoader() {
   mHandler.postDelayed(stopTask, 1000);
}

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