处理滑动冲突：外部拦截标准模板

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package com.example.apple.quickdemo.realview;import android.content.Context;import android.support.annotation.Nullable;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.view.VelocityTracker;import android.widget.LinearLayout;import android.widget.Scroller;import static android.content.ContentValues.TAG;/** * Created by apple on 2017/7/7. * 外部拦截标准模板 */public class RealPullRefreshView extends LinearLayout {    private int mTouchSlop;    //    分别记录上次滑动的坐标    private int mLastX = 0;    private int mLastY = 0;    //    分别记录上次滑动的坐标(onInterceptTouchEnvent)    private int mLastXIntercept = 0;    private int mLastYIntercept = 0;    private Scroller mScroller;    private VelocityTracker mVelocityTracker;    private RecyclerView mRv;    public RealPullRefreshView(Context context) {        super(context);        init();    }    public RealPullRefreshView(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);        init();    }    private void init() {        mScroller = new Scroller(getContext());        mVelocityTracker = VelocityTracker.obtain();    }    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);        mRv = (RecyclerView) getChildAt(1);    }    @Override    public boolean onInterceptTouchEvent(MotionEvent event) {        boolean intercepted = false;        int x = (int) event.getX();        int y = (int) event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN: {                intercepted = false;                if (!mScroller.isFinished()) {                    mScroller.abortAnimation();                    intercepted = true;                }                break;            }            case MotionEvent.ACTION_MOVE: {                int deltaX = x - mLastXIntercept;                int deltaY = y - mLastYIntercept;                //               ******************这里说明什么规则下，拦截，其余代码不要动了，其余代码指的是处理滑动冲突的代码***************                int firstCompletelyVisibleItemPosition = ((LinearLayoutManager) mRv.getLayoutManager()).findFirstCompletelyVisibleItemPosition();                if (firstCompletelyVisibleItemPosition == 0 && deltaY > 0) {//拉倒最顶部，继续往下拉，将拉出头布局，要父布局拦截                    intercepted = true;                } else if (getScrollY() < 0) {//表示头布局已经向下拉出来，头布局已经显示了，要父布局拦截                    intercepted = true;                } else {                    intercepted = false;//不要父布局拦截了                }                //                ******************什么规则下，拦截***************                break;            }            case MotionEvent.ACTION_UP: {                intercepted = false;                break;            }            default:                break;        }        Log.d(TAG, "intercepted=" + intercepted);        mLastX = x;        mLastY = y;        mLastXIntercept = x;        mLastYIntercept = y;        return intercepted;    }    /**     * 下面不同布局，不同的滑动需求     * @param event     * @return     */    @Override    public boolean onTouchEvent(MotionEvent event) {        mVelocityTracker.addMovement(event);        int x = (int) event.getX();        int y = (int) event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN: {                if (!mScroller.isFinished()) {                    mScroller.abortAnimation();                }                break;            }            case MotionEvent.ACTION_MOVE: {                Log.e("111", getScrollY() + "");                int deltaX = x - mLastX;                int deltaY = y - mLastY;                if (getScrollY() > 0) {                    scrollTo(0, 0);//抖动                } else {                    scrollBy(0, -deltaY);                }                break;            }            case MotionEvent.ACTION_UP: {                int scrollY = getScrollY();                if (scrollY > -105) {//头布局显示了不到一半，完全隐藏头布局                    smoothScrollBy(0, -scrollY);                } else if (scrollY < -105) {//头布局显示了超过到一半，完全显示头布局                    smoothScrollBy(0, -210 - scrollY);                }                mVelocityTracker.clear();                break;            }            default:                break;        }        mLastX = x;        mLastY = y;        return true;    }    private void smoothScrollBy(int dx, int dy) {        mScroller.startScroll(0, getScrollY(), 0, dy, 500);        invalidate();    }    @Override    public void computeScroll() {        if (mScroller.computeScrollOffset()) {            scrollTo(mScroller.getCurrX(), mScroller.getCurrY());            postInvalidate();        }    }    @Override    protected void onDetachedFromWindow() {        mVelocityTracker.recycle();        super.onDetachedFromWindow();    }}
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