android滚动查看详细信息，如whatsup

Question

放置一些图标，如向下箭头，让用户可以知道有一些细节显示在android下。

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滚动页面结束后，滚动箭头将消失。

Answer 1

 scrollView1.getViewTreeObserver().addOnScrollChangedListener(new OnScrollChangedListener() {

         public void onScrollChanged() {

           int scrollViewHeight = scrollView1.getChildAt(0).getHeight();


           Log.e("scrollVIEW_height", "SCROLL" + scrollViewHeight);

           double size = 0;

           DisplayMetrics dm = mContext.getResources().getDisplayMetrics();

           float screenWidth = dm.widthPixels / dm.xdpi;

           float screenHeight = dm.heightPixels / dm.ydpi;

           float i = dm.heightPixels;

           Log.e("height in i", "" + i);

           double heightininch = Math.sqrt(Math.pow(screenHeight, 2));

           Log.e("height in inch", "" + heightininch);

           size = Math.sqrt(Math.pow(screenWidth, 2) + Math.pow(screenHeight, 2));

           Log.e("screen", "" + size);

           if (size >= 6) {

             if (scrollViewHeight >= (int)i) {

               DownIndicator.setVisibility(View.VISIBLE);

               // TopIndicator.setVisibility(View.VISIBLE);

             }
           }
        }
    });