如何滚动到长 ScrollView 布局的顶部？

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!

Answer 1

Try

mainScrollView.fullScroll(ScrollView.FOCUS_UP);

it should work.

Answer 2

Had the same issue, probably some kind of bug.

Even the fullScroll(ScrollView.FOCUS_UP) from the other answer didn't work.
Only thing that worked for me was calling scroll_view.smoothScrollTo(0,0) right after the dialog is shown.

Answer 3

i had the same problem and this fixed it. Hope it helps you.

listView.setFocusable(false);

Answer 4

scrollViewObject.fullScroll(ScrollView.FOCUS_UP) this works fine, but only the problem with this line is that, when data is populating in scrollViewObject, has been called immediately. You have to wait for some milliseconds until data is populated. Try this code:

scrollViewObject.postDelayed(new Runnable() {
    @Override
    public void run() {
        scroll.fullScroll(ScrollView.FOCUS_UP);
    }
}, 600);

OR

 scrollViewObject.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        scrollViewObject.getViewTreeObserver().removeOnGlobalLayoutListener(this);
        scrollViewObject.fullScroll(View.FOCUS_UP);
    }
});

Answer 5

The main problem to all these valid solutions is that you are trying to move up the scroll when it isn't drawn on screen yet.

You need to wait until scroll view is on screen, then move it to up with any of these solutions. This is better solution than a postdelay, because you don't mind about the delay.

    // Wait until my scrollView is ready
    scrollView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            // Ready, move up
            scrollView.fullScroll(View.FOCUS_UP);
        }
    });

Answer 6

Very easy

    ScrollView scroll = (ScrollView) findViewById(R.id.addresses_scroll);
    scroll.setFocusableInTouchMode(true);
    scroll.setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);

Answer 7

I faced Same Problem When i am using Scrollview inside View Flipper or Dialog that case scrollViewObject.fullScroll(ScrollView.FOCUS_UP) returns false so that case scrollViewObject.smoothScrollTo(0, 0) is Worked for me

Scroll Focus Top

Answer 8

 final ScrollView scrollview = (ScrollView)findViewById(R.id.selected_place_layout_scrollview);

         scrollview.post(new Runnable() { 
                public void run() { 
                    scrollview.scrollTo(0, 0); 
                } 
            }); 

Answer 9

这对我有用

scroll_view.smoothScrollTo(0,0); // scroll to top of screen

Answer 10

runOnUiThread( new Runnable(){
   @Override
   public void run(){
      mainScrollView.fullScroll(ScrollView.FOCUS_UP);
   }
}

Answer 11

I fixed my issue in Kotlin like this:

scrollview.isFocusableInTouchMode = true
scrollview.fullScroll(View.FOCUS_UP)
scrollview.smoothScrollTo(0,0)

You can also create an extension of this like:

ScrollView.moveToTop()
{
    this.isFocusableInTouchMode = true
    this.fullScroll(View.FOCUS_UP)
    this.smoothScrollTo(0,0)
}

and use it like:

scrollView.moveToTop()

Answer 12

This is force scroll for scrollview :

            scrollView.post(new Runnable() {
                @Override
                public void run() {
                    scrollView.scrollTo(0, 0);
                    scrollView.pageScroll(View.FOCUS_UP);
                    scrollView.smoothScrollTo(0,0);
                }
            });

Answer 13

scrollView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        // Ready, move up
        scrollView.fullScroll(View.FOCUS_UP);
    }
});

Answer 14

This solution also works for NestedScrollView

NestedScrollView nestedScrollView = view.findViewById(R.id.YourNestedScrollViewID);
nestedScrollView.fullScroll(ScrollView.FOCUS_UP);

Answer 15

@SuppressWarnings({ "deprecation", "unchecked" })
public void swipeTopToBottom(AppiumDriver<MobileElement> driver) 
                    throws InterruptedException {
       Dimension dimensions = driver.manage().window().getSize();
        Double screenHeightStart = dimensions.getHeight() * 0.30;
        int scrollStart = screenHeightStart.intValue();
        System.out.println("s="+scrollStart);
        Double screenHeightEnd = dimensions.getHeight()*0.90;
        int scrollEnd = screenHeightEnd.intValue();
        driver.swipe(0,scrollStart,0,scrollEnd,2000);
        CommonUtils.threadWait(driver, 3000);
    }

Answer 16

A few years later, the only proper solution is a mix of this thread:

• without a listener or a post delayed handler, simpler solutions will fail because the can try to scroll before the ScrollView is drawn on the screen like explained by @Pelanes
• the most proposed answer scan_settings_sv.fullScroll(View.FOCUS_UP); will move view to the first focusable element, not necessarily the top of scroll view. So, if there is a header or some text, or disabled views greyed out, and and a TextView below them, the ScrollView will move up to the TextView and not ScrollView Header
• Like @Nilhcem commented, we need to remove the listener at the end, else the ScrollView will keep moving up
• I also implemented it with the global OnGlobalLayoutListener reference as method argument to fix compiler warnings

So, the final solution should implement view.smoothScrollTo(0,0); , combined with OnGlobalLayoutListener to ensure the view was properly drwan on screen:

final ScrollView my_view= dialog.findViewById(R.id.my_view_id);
scan_settings_sv.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        // Ready, move up
        //my_view.fullScroll(View.FOCUS_UP); //moves up to the to selectable/focusable element
        my_view.smoothScrollTo(0,0); // scrolls to top of view
        my_view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
    }
});

Note that it is very important to get the ScrollView just before invoking the method! Else, if the view height changed after the first final ScrollView my_view= dialog.findViewById(R.id.my_view_id); invocation, for example because a ListView below the ScrollView was expanded, the scroll will not properly reach top of the ScrollView