继承NestedScrollView 实现可滑动的效果, 在onInterceptTouchEvent 中处理了横向滑动,在需要处理的时候直接调用setNeedScroll为flase时即可
package com.sumansoul.onmat.curricula.widget;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.widget.ScrollView;
import androidx.core.widget.NestedScrollView;
/**
* 下拉放大第一个view
* @author anxinlong
* @since 2023/5/13 12:56 PM
*/
public class AmplifyFirstScrollView extends NestedScrollView implements View.OnTouchListener {
// 记录首次按下位置
private float mFirstPosition = 0;
// 是否正在放大
private Boolean mScaling = false;
private View dropZoomView;
private int dropZoomViewWidth;
private int dropZoomViewHeight;
private boolean isNeedScroll = true;
private int scaledTouchSlop;
public AmplifyFirstScrollView(Context context) {
super(context);
}
public AmplifyFirstScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public AmplifyFirstScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
scaledTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
}
@Override
protected void onFinishInflate() {
super.onFinishInflate();
init();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
private void init() {
setOverScrollMode(OVER_SCROLL_NEVER);
if (getChildAt(0) != null) {
ViewGroup vg = (ViewGroup) getChildAt(0);
if (vg.getChildAt(0) != null) {
dropZoomView = vg.getChildAt(0);
setOnTouchListener(this);
}
}
}
@Override
public boolean onTouch(View v, MotionEvent event) {
if (dropZoomViewWidth <= 0 || dropZoomViewHeight <= 0) {
dropZoomViewWidth = dropZoomView.getMeasuredWidth();
dropZoomViewHeight = dropZoomView.getMeasuredHeight();
}
switch (event.getAction()) {
case MotionEvent.ACTION_UP:
//手指离开后恢复图片
mScaling = false;
replyImage();
break;
case MotionEvent.ACTION_MOVE:
if (!mScaling) {
if (getScrollY() == 0) {
mFirstPosition = event.getY();// 滚动到顶部时记录位置,否则正常返回
} else {
break;
}
}
int distance = (int) ((event.getY() - mFirstPosition) * 0.6); // 滚动距离乘以一个系数
if (distance <0) { // 当前位置比记录位置要小,正常返回
break;
}
// 处理放大
mScaling = true;
setZoom(1 + distance);
return true; // 返回true表示已经完成触摸事件,不再处理
}
return false;
}
private float xDistance, yDistance, xLast, yLast;
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
Log.i("TAG", "onInterceptTouchEvent: ");
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
xDistance = yDistance = 0f;
xLast = ev.getX();
yLast = ev.getY();
break;
case MotionEvent.ACTION_MOVE:
final float curX = ev.getX();
final float curY = ev.getY();
xDistance += Math.abs(curX - xLast);
yDistance += Math.abs(curY - yLast);
xLast = curX;
yLast = curY;
Log.e("SiberiaDante", "xDistance :" + xDistance + "---yDistance:" + yDistance);
return !(xDistance >= yDistance || yDistance < scaledTouchSlop) && isNeedScroll;
}
return super.onInterceptTouchEvent(ev);
}
// 回弹动画 (使用了属性动画)
public void replyImage() {
final float distance = dropZoomView.getMeasuredWidth() - dropZoomViewWidth;
// 设置动画
ValueAnimator anim = ObjectAnimator.ofFloat(0.0F, 1.0F).setDuration((long) (distance * 0.7));
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
float cVal = (Float) animation.getAnimatedValue();
setZoom(distance - ((distance) * cVal));
}
});
anim.start();
}
//缩放
public void setZoom(float s) {
if (dropZoomViewHeight <= 0 || dropZoomViewWidth <= 0) {
return;
}
ViewGroup.LayoutParams lp = dropZoomView.getLayoutParams();
lp.width = (int) (dropZoomViewWidth + s);
lp.height = (int) (dropZoomViewHeight * ((dropZoomViewWidth + s) / dropZoomViewWidth));
dropZoomView.setLayoutParams(lp);
}
/*
该方法用来处理NestedScrollView是否拦截滑动事件
*/
public void setNeedScroll(boolean isNeedScroll) {
this.isNeedScroll = isNeedScroll;
}
}