How to make ScrollView scroll while button is pressed?

Question

my problem is quite simple actually, I couldn't find a way to do what's mentionned in my question. I tried with AsyncTask, which didn't work at all, also with the OnFocusChange event of the button... I'm a bit desperate at now.

Hope you guys could help ! :)

AsyncTask Version :

private void creationVoid(){
    (...)
    btScrollDown.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if(event.getAction() == MotionEvent.ACTION_DOWN)
                downPressed = true;
            if(event.getAction() == MotionEvent.ACTION_UP)
                downPressed = false;
            new ScrollDownTask().execute();
            return true;
        }
    });
(...)
}


private void scrollDown(){
    btScrollUp.setVisibility(View.VISIBLE);
    scrollView.scrollTo(scrollView.getScrollX(), scrollView.getScrollY() + 15);
    if(scrollView.getScrollY() == scrollView.getChildAt(scrollView.getChildCount()-1).getBottom() - 763) {
        btScrollDown.setVisibility(View.GONE);
    }
}

private class ScrollDownTask extends AsyncTask<String, Void, String>{
    @Override
    protected String doInBackground(String... params) {return null;}

    @Override
    protected void onPostExecute(String s) {
        while(downPressed)
            scrollDown();
    }
}

OnFocusChange Version :

private void creationVoid(){
    (...)
    btScrollDown.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            while(hasFocus)
                scrollDown();
        }
    });
    (...)
}

Please add your code of what you have tried so far. – yennsarah May 26 '16 at 08:31 — yennsarah, May 26 '16 at 08:31

score 1 · Answer 1 · answered May 26 '16 at 08:34

1

When the button is pressed, you can call the smoothScrollBy or the smoothScrollTo method. You have to, however,based on your requirement calculate how much to scroll the view. Hope this helps.

https://developer.android.com/reference/android/widget/ScrollView.html#smoothScrollBy(int,%20int)

answered May 26 '16 at 08:34

Anirudh R Kashyap

104
4

I don't know because I need to scroll repeatedly, which is the main problem, but this helps for another purposes thanks for sharing ! – ArteFact May 26 '16 at 08:37
Look at this http://stackoverflow.com/questions/13737754/put-the-scroll-view-under-the-up-and-down-button. Seems very close to what you want. – Anirudh R Kashyap May 26 '16 at 09:31

score 1 · Answer 2 · answered May 26 '16 at 08:48

Here's my approach.

Start a timer when you press the button and cancel the timer when you lift the touch from the button
On the timer fired method, scroll by a certain value (y).

Fine tune the timer interval and the scrollBy value y to suite your requirement.

How to make ScrollView scroll while button is pressed?

2 Answers2