How to scroll to top of long ScrollView layout?


Question

For part of my app, the user is presented with a list of names and is asked to group them as they see fit.

(Note, the ListView code was copied verbatim from the Android Views tutorial. I haven't yet customized it to my needs, I'm just trying to figure out how to make this work.)

The basic layout is a LinearLayout, containing a ScrollView (called "groupsScrollView" in the code below), containing a RelativeLayout. I have some buttons and text, and then my ListView beneath that, which displays the list of names. All this is taller than the visible screen area, so the user is allowed to scroll vertically to see it all.

This all works beautifully, except when the page loads it is always pre-scrolled to the top of my ListView - in the middle of the page. The text and buttons I've created that tell the user what to do are not visible.

I can grab the screen and scroll up, that works just fine, but I'd like the screen to load having already been scrolled to the top. The user shouldn't have to scroll UP to see the top of a freshly loaded page. But everything I've tried to programmatically scroll to the top of the screen has failed.

Here's my onCreate method:

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.groups);

    mainScrollView = (ScrollView)findViewById(R.id.groupsScrollView);

    //get the Bundle out of the Intent...
    Bundle extras = getIntent().getExtras();
    mNames = extras.getStringArray("mNames");

    setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item, mNames));

    ListView lv = getListView();
    lv.setTextFilterEnabled(true);

    //This is the line I'm having issues with
    mainScrollView.pageScroll(View.FOCUS_UP);

    lv.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view,
            int position, long id) {
          // When clicked, show a toast with the TextView text
          Toast.makeText(getApplicationContext(), ((TextView) view).getText(),
              Toast.LENGTH_SHORT).show();
        }
      });
}

The line "mainScrollView.pageScroll(View.FOCUS_UP); is the problem. It doesn't cause an error, but it doesn't seem to do anything. I've tried scrollTo(0,0), scrollDirection(View.FOCUS_UP), and everything else I can think of.

Since I don't get an error I have to assume that these scroll commands are actually working, but that they're scrolling to the top of the ListView, rather than the top of the ScrollView or RelativeLayout that contains it. This seems to be confirmed by Google's own description of the scrollTo(int x, int y) method where they say "This version also clamps the scrolling to the bounds of our child.".

So to make a long question even longer, how do I load a bunch of views on the screen contained within a ScrollView, and then programmatically scroll the whole thing to the top of the page so the user can interact with it?

Thanks!

1
153
11/7/2010 8:04:32 PM

Try

mainScrollView.fullScroll(ScrollView.FOCUS_UP);

it should work.

248
1/20/2014 7:48:18 AM

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