Detect if a ScrollView is scrolling up or down - Android

问题

I have one ScrollView with one LinearLayout with TextViews. I want to detect when ScrollView is scrolling up or down to hide/show ActionBar.

回答1:

you need to create a class that extends ScrollView

public class ExampleScrollView extends ScrollView 

and then Override onScrollChanged that gives you the old and new scroll positions and from there you can detect which direction

protected void onScrollChanged(int l, int t, int oldl, int oldt) 

回答2:

check this out

scrollView.setOnTouchListener(new View.OnTouchListener() {
  float y0 = 0;
  float y1 = 0;

  @Override
  public boolean onTouch(View view, MotionEvent motionEvent) {

    if (motionEvent.getAction() == MotionEvent.ACTION_MOVE) {
      y0 = motionEvent.getY();
      if (y1 - y0 > 0) {
        Log.i("Y", "+");
        AnimateFloat(true);
      } else if (y1 - y0 < 0) {
        Log.d("Y", "-");
        AnimateFloat(false);
      }
      y1 = motionEvent.getY();
    }

    return false;
  }
});

回答3:

A sure short answer

scroll.setOnScrollChangeListener(new View.OnScrollChangeListener() {
    @Override
    public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {


                int x = scrollY - oldScrollY;
                if (x > 0) {
                    //scroll up
                } else if (x < 0) {
                    //scroll down
                } else {

                }

    }
});

来源：https://stackoverflow.com/questions/27297467/detect-if-a-scrollview-is-scrolling-up-or-down-android