Adjust scroll position when soft keyboard opens

Question

I have a form within a ScrollView. When I tap into an EditText the soft keyboard appears and the ScrollView scrolls the now focused EditText so that it just comes into view.

However, I have hint information just below the EditText that I also would like to show, so the scrolling should go just a bit further up, like this:

The EditText is embedded in a form element and actually I'd like to scroll to the bottom of that. I've checked the source code of ScrollView and it will just scroll to the bottom of the currently focused view. Maybe there's a way to tell the ScrollView that the form element is the currently focused element?

Of course I could write my own ScrollView sub class and override the scroll behavior, but I wonder if there's a more elegant way of doing this.

Any other suggestions (with adjust scrolling with a fixed offset or so) are also appreciated.

Answer 1

I have not really found any way to configure the scrolling behavior of the ScrollView from the outside. So I ended up to define my own sub class of ScrollView:`

/**
 * {@link ScrollView} extension that allows to configure scroll offset.
 */
public class ConfigurableScrollView extends ScrollView {

  private int scrollOffset = 0;

  public ConfigurableScrollView (final Context context, final AttributeSet attrs) {
    super(context, attrs);
  }

  public void setScrollOffset (final int scrollOffset) {
    this.scrollOffset = scrollOffset;
  }

  @Override
  protected int computeScrollDeltaToGetChildRectOnScreen (final Rect rect) {
    // adjust by scroll offset
    int scrollDelta = super.computeScrollDeltaToGetChildRectOnScreen(rect);
    int newScrollDelta = (int) Math.signum(scrollDelta) * (scrollDelta + this.scrollOffset);
    return newScrollDelta;
  }
}

computeScrollDelta(...) is the only protected method that can be targeted for overriding, apart from onSizeChanged(...).

The signum function in the example above ensures that scrolling is only increased, if the ScrollView really thinks that scrolling is necessary (e.g. when keyboard pops up).

I can now set the extra scroll offset once from the outside, as calculated from the height of the hint.

It's not hard to use the extended ConfigurableScrollView instead of the standard ScrollView, I only had to replace the ScrollView XML tag with the FQN of the new class.