Android:自定义底页对话框

这可以通过滚动视图中的if语句完成,如下所示:

ScrollView scrollView = findViewById(R.id.scrollView); //Adjust for your code
ImageView imageView = findViewById(R.id.imageView); //Adjust for your code
boolean imageIsHidden = false;
int threshold = 250;
scrollView.getViewTreeObserver().addOnScrollChangedListener(new OnScrollChangedListener() {
    @Override
    public void onScrollChanged() {
        int scrollY = rootScrollView.getScrollY();
        if(scrollY >= threshold){
            imageIsHidden = true;
            //Move image outside of scroll view so it doesn't scroll
        }
        else if(scrollY < threshold && imageIsHidden){
            imageIsHidden = false;
            //Move image inside of scroll view so it does scroll
        }
    }
});    

imageIsHidden 一个整数叫做 threshold . 门槛是你想让它消失的地方。你需要利用这个价值来找到一个好地方。