自定义recyclerView布局管理器
在设置管理器的时候调用就可实现
package com.http.user.utils;
import android.content.Context;
import android.view.View;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.PagerSnapHelper;
import androidx.recyclerview.widget.RecyclerView;
import com.dingmouren.layoutmanagergroup.viewpager.OnViewPagerListener;
public class ViewPagerLayoutManager extends LinearLayoutManager {
private static final String TAG = "ViewPagerLayoutManager";
private PagerSnapHelper mPagerSnapHelper;
private OnViewPagerListener mOnViewPagerListener;
private RecyclerView mRecyclerView;
private int mDrift;//位移,用来判断移动方向
public ViewPagerLayoutManager(Context context, int orientation) {
super(context, orientation, false);
init();
}
public ViewPagerLayoutManager(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
init();
}
private void init() {
mPagerSnapHelper = new PagerSnapHelper();
}
@Override
public void onAttachedToWindow(RecyclerView view) {
super.onAttachedToWindow(view);
view.setOnFlingListener(null);
mPagerSnapHelper.attachToRecyclerView(view);
this.mRecyclerView = view;
mRecyclerView.addOnChildAttachStateChangeListener(mChildAttachStateChangeListener);
}
@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
try {
//try catch一下
super.onLayoutChildren( recycler, state );
} catch (IndexOutOfBoundsException e) {
e.printStackTrace();
}
//
}
/**
* 滑动状态的改变
* 缓慢拖拽-> SCROLL_STATE_DRAGGING
* 快速滚动-> SCROLL_STATE_SETTLING
* 空闲状态-> SCROLL_STATE_IDLE
* @param state
*/
@Override
public void onScrollStateChanged(int state) {
switch (state) {
case RecyclerView.SCROLL_STATE_IDLE:
View viewIdle = mPagerSnapHelper.findSnapView(this);
int positionIdle = getPosition(viewIdle);
if (mOnViewPagerListener != null && getChildCount() == 1) {
mOnViewPagerListener.onPageSelected(positionIdle,positionIdle == getItemCount() - 1);
}
break;
case RecyclerView.SCROLL_STATE_DRAGGING:
View viewDrag = mPagerSnapHelper.findSnapView(this);
int positionDrag = getPosition(viewDrag);
break;
case RecyclerView.SCROLL_STATE_SETTLING:
View viewSettling = mPagerSnapHelper.findSnapView(this);
int positionSettling = getPosition(viewSettling);
break;
}
}
/**
* 监听竖直方向的相对偏移量
* @param dy
* @param recycler
* @param state
* @return
*/
@Override
public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
this.mDrift = dy;
return super.scrollVerticallyBy(dy, recycler, state);
}
/**
* 监听水平方向的相对偏移量
* @param dx
* @param recycler
* @param state
* @return
*/
@Override
public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
this.mDrift = dx;
return super.scrollHorizontallyBy(dx, recycler, state);
}
/**
* 设置监听
* @param listener
*/
public void setOnViewPagerListener(OnViewPagerListener listener){
this.mOnViewPagerListener = listener;
}
private RecyclerView.OnChildAttachStateChangeListener mChildAttachStateChangeListener = new RecyclerView.OnChildAttachStateChangeListener() {
@Override
public void onChildViewAttachedToWindow(View view) {
if (mOnViewPagerListener != null && getChildCount() == 1) {
mOnViewPagerListener.onInitComplete();
}
}
@Override
public void onChildViewDetachedFromWindow(View view) {
if (mDrift >= 0){
if (mOnViewPagerListener != null) mOnViewPagerListener.onPageRelease(true,getPosition(view));
}else {
if (mOnViewPagerListener != null) mOnViewPagerListener.onPageRelease(false,getPosition(view));
}
}
};
}