我应该为我的Android应用程序使用什么EVENT LISTENER

Question

In my app, when one particular image button is clicked and held, i must be able to calculate the time for which the image button was held pressed. Can any one help me by giving some simple guidance or sample code. i am really stuck up here. Is there any specific event listener for this particular requirement. I am writing this app specifically for a touch screen phones only.

Answer 1

What you want to use is this:

OnTouchListener touchListener = new OnTouchListener(){
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        int action = event.getAction();
        Log.d(LOG_TAG, "Action is: " + action);

        switch (action){
        case MotionEvent.ACTION_DOWN:
            timeAtDown = SystemClock.elapsedRealtime();
            break;

        case MotionEvent.ACTION_UP:
            long durationOfTouch = SystemClock.elapsedRealtime() - timeAtDown;
            Log.d(LOG_TAG, "Touch event lasted " + durationOfTouch + " milliseconds.");
            break;
        }
        return false;
    }

};

button.setOnTouchListener(touchListener);

timeAtDown is a long defined as a class field, since it needs to persist between calls to the touchListener. Using this you don't interfere with the button's normal operation either; you can set a click listener which will function properly. Note: The 'click' operation doesn't happen until the touch event's action goes from DOWN (or MOVE) to UP.

Answer 2

Experiment with the on*** callbacks from http://developer.android.com/reference/android/view/KeyEvent.Callback.html .

For example Button.onKeyDown, save the current time in a variable and Button.onKeyDown calculate the difference from last saved time.