问有没有办法识别滚动视图在android中向上或向下滚动？
EN

Stack Overflow用户

提问于 2015-01-09 12:24:17

回答 4查看 9.8K关注 0票数 5

嘿，我只是想知道在android .Wanted中滚动视图是向上还是向下滚动，以便在向上和向下滚动时执行不同的操作。

任何想法都很受欢迎，谢谢

android

scrollview

回答 4

Stack Overflow用户

发布于 2016-02-12 14:51:56

尝试一下:扩展Scrollview并重写onTouchEvent方法

private float mTouchPosition;
private float mReleasePosition;

@Override
public boolean onTouchEvent(MotionEvent event) {

    if (event.getAction() == MotionEvent.ACTION_DOWN) {
        mTouchPosition = event.getY();
    }
    if (event.getAction() == MotionEvent.ACTION_UP) {
        mReleasePosition = event.getY();

        if (mTouchPosition - mReleasePosition > 0) {
            // user scroll down
        } else {
            //user scroll up
        }
    }
    return super.onTouchEvent(event);
}

票数 7

Stack Overflow用户

发布于 2019-06-26 13:22:13

试试这个，它对我很管用

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        scrollView.setOnScrollChangeListener(new View.OnScrollChangeListener() {
            @Override
            public void onScrollChange(View v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
                 if(scrollY<=oldScrollY)
                {
                    //scroll up
                    relativeLayout.setVisibility(View.VISIBLE);
                }
                else {
                relativeLayout.setVisibility(View.GONE);}
            }
        });
    }

票数 6

Stack Overflow用户

发布于 2017-11-12 06:54:23

是的，你可以用这个

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

        }
    });

但这要求minSdkVersion必须是23岁。因此，您可以将minSdkVersion更改为23，或者创建一个自定义滚动视图，如下所示：

public class TouchDetectableScrollView extends ScrollView  {

OnMyScrollChangeListener myScrollChangeListener;

public TouchDetectableScrollView(Context context) {
    super(context);
}

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

public TouchDetectableScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}

@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    super.onScrollChanged(l, t, oldl, oldt);

    if (myScrollChangeListener!=null)
    {
        if (t>oldt)
        {
            myScrollChangeListener.onScrollDown();
        }
        else if (t<oldt){
            myScrollChangeListener.onScrollUp();
        }

    }
}

public OnMyScrollChangeListener getMyScrollChangeListener() {
    return myScrollChangeListener;
}

public void setMyScrollChangeListener(OnMyScrollChangeListener myScrollChangeListener) {
    this.myScrollChangeListener = myScrollChangeListener;
}

public interface OnMyScrollChangeListener
{
        public void onScrollUp();
        public void onScrollDown();
}}

在xml和java代码中使用TouchDetectableScrollView，然后像这样设置listener：

scrollView.setMyScrollChangeListener(new TouchDetectableScrollView.OnMyScrollChangeListener() {
        @Override
        public void onScrollUp() {
            //Toast.makeText(getActivity(), "Scrolling up", Toast.LENGTH_SHORT).show();
            Log.d("scroll","up");

        }

        @Override
        public void onScrollDown() {
           // Toast.makeText(getActivity(), "Scrolling down", Toast.LENGTH_SHORT).show();
            Log.d("scroll","down");

        }
    });