Repeat A Task With A Time Delay Inside A Custom View

The question Repeat a task with a time delay? talks about a repeated task within an activity. The top voted answer looks good for that situation. I am trying to make a blinking cur

Solution 1:

The following example shows how to set a repeating task on a custom view. The task works by using a handler that runs some code every second. Touching the view starts and stops the task.

publicclassMyCustomViewextendsView {

    privatestaticfinalintDELAY=1000; // 1 secondprivate Handler mHandler;

    // keep track of the current color and whether the task is runningprivatebooleanisBlue=true;
    privatebooleanisRunning=false;

    // constructorspublicMyCustomView(Context context) {
        this(context, null, 0);
    }
    publicMyCustomView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }
    publicMyCustomView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    privatevoidinit() {
        mHandler = newHandler();
    }

    // start or stop the blinking when the view is touched@OverridepublicbooleanonTouchEvent(MotionEvent event) {

        if (event.getAction() == MotionEvent.ACTION_UP) {
            if (isRunning) {
                stopRepeatingTask();
            } else {
                startRepeatingTask();
            }
            isRunning = !isRunning;
        }
        returntrue;
    }

    // alternate the view's background colorRunnablemRunnableCode=newRunnable() {
        @Overridepublicvoidrun() {
            if (isBlue) {
                MyCustomView.this.setBackgroundColor(Color.RED);
            }else {
                MyCustomView.this.setBackgroundColor(Color.BLUE);
            }
            isBlue = !isBlue;

            // repost the code to run again after a delay
            mHandler.postDelayed(mRunnableCode, DELAY);
        }
    };

    // start the taskvoidstartRepeatingTask() {
        mRunnableCode.run();
    }

    // stop running the task, cancel any current code that is waiting to runvoidstopRepeatingTask() {
        mHandler.removeCallbacks(mRunnableCode);
    }

    // make sure that the handler cancels any tasks left when the view is destroyed @OverrideprotectedvoidonDetachedFromWindow() {
        super.onDetachedFromWindow();
        stopRepeatingTask();
    }
}

Here is what the view looks like after being clicked.

Thanks to this answer for ideas.