Android 可上下拖拽LinearLayout

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package com.jr.jingren.view;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.ViewGroup;import android.view.animation.DecelerateInterpolator;import android.widget.AdapterView;import android.widget.LinearLayout;import android.widget.ScrollView;import android.widget.Scroller;/** * Created by Administrator on 2016/7/20. * 可滑动LinearLayout */public class SlideView extends LinearLayout {    private float mLastY = -1;    private float xDistance, yDistance, xLast, yLast;    private AdapterView<?> mAdapterView;    private ScrollView mScrollView;    private View scrollContent;    private final int SCROLL_DURATION = 200; // 滚动回时间    private Scroller mScroller;    private boolean isIntercept;    public SlideView(Context context) {        super(context);        init(context);    }    public SlideView(Context context, AttributeSet attrs) {        super(context, attrs);        init(context);    }    public SlideView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init(context);    }    private void init(Context context) {        mScroller = new Scroller(context, new DecelerateInterpolator());    }    @Override    protected void onFinishInflate() {        super.onFinishInflate();        traversalView(this);    }    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        switch (ev.getAction()) {            case MotionEvent.ACTION_DOWN:                xDistance = yDistance = 0f;                xLast = ev.getX();                yLast = ev.getY();                mLastY = ev.getRawY();                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;                if (xDistance > yDistance)                    isIntercept = true;        }        return super.onInterceptTouchEvent(ev);    }    @Override    public boolean dispatchTouchEvent(MotionEvent ev) {        int scrollY = getScrollY();        switch (ev.getAction()) {            case MotionEvent.ACTION_DOWN:                isIntercept = false;                mLastY = ev.getRawY();                if (!mScroller.isFinished())                    mScroller.forceFinished(true);                break;            case MotionEvent.ACTION_MOVE:                if (isIntercept) break;                final float deltaY = ev.getRawY() - mLastY;                mLastY = ev.getRawY();                float speedY = Math.abs(scrollY / 80);//计算加速度                if (speedY < 3)                    speedY = 3;                int sbY = -(int) (deltaY / speedY);                if (mScrollView != null && scrollContent != null) {// 对于ScrollView                    // 主要判断不得移出屏幕之外，必须在屏幕可见范围移动                    if (scrollY <= 0 && mScrollView.getScrollY() == 0) {//顶部活动且不能低于0                        if (scrollContent.getMeasuredHeight() > getHeight() + mScrollView.getScrollY() && sbY + scrollY > 0)                            sbY = -scrollY;                        scrollBy(0, sbY);                    } else if (scrollY >= 0 && scrollContent.getMeasuredHeight() <= getHeight() + mScrollView.getScrollY()) {//底部活动且不能高于0                        if (sbY + scrollY < 0)                            sbY = -scrollY;                        scrollBy(0, sbY);                    }                } else if (mAdapterView != null && mAdapterView.getChildAt(0) != null && mAdapterView.getChildAt(mAdapterView.getChildCount() - 1) != null) {                    // 主要判断不得移出屏幕之外，必须在屏幕可见范围移动                    if (scrollY <= 0 && mAdapterView.getFirstVisiblePosition() == 0 && (mAdapterView.getChildAt(0).getTop() == 0 || mAdapterView.getChildAt(0).getTop() - mAdapterView.getPaddingTop() == 0)) {//顶部活动且不能低于0                        if (mAdapterView.getChildAt(mAdapterView.getChildCount() - 1).getBottom() > getHeight() && sbY + scrollY > 0)                            sbY = -scrollY;                        scrollBy(0, sbY);                    } else if (scrollY >= 0 && mAdapterView.getChildAt(mAdapterView.getChildCount() - 1).getBottom() <= getHeight() && mAdapterView.getLastVisiblePosition() == mAdapterView.getCount() - 1) {//底部活动且不能高于0                        if (sbY + scrollY < 0)                            sbY = -scrollY;                        scrollBy(0, sbY);                    }                } else {                    scrollBy(0, sbY);                }                break;            case MotionEvent.ACTION_UP:                if (scrollY != 0) {                    mScroller.startScroll(0, scrollY, 0, -scrollY, SCROLL_DURATION);                    invalidate();                }                break;        }        return super.dispatchTouchEvent(ev);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        return true;    }    @Override    public void computeScroll() {        if (mScroller.computeScrollOffset()) {            scrollTo(0, mScroller.getCurrY());            invalidate();        }        super.computeScroll();    }    /**     * 遍历所有view,判断子控件中的第一个是否含有可滑动控件     *     * @param viewGroup     */    public void traversalView(ViewGroup viewGroup) {        int count = viewGroup.getChildCount();        if (mScrollView != null || mAdapterView != null) return;        for (int i = 0; i < count; i++) {            View view = viewGroup.getChildAt(i);            if (view instanceof ScrollView) {                mScrollView = (ScrollView) view;                scrollContent = mScrollView.getChildAt(0);                mScrollView.setOnTouchListener(new OnTouchListener() {//当弹性还未恢复时，禁止子控件自己滑动                    @Override                    public boolean onTouch(View v, MotionEvent event) {                        if (getScrollY() != 0)                            return true;                        return false;                    }                });            } else if (view instanceof AdapterView<?>) {                mAdapterView = (AdapterView<?>) view;                mAdapterView.setOnTouchListener(new OnTouchListener() {//当弹性还未恢复时，禁止子控件自己滑动                    @Override                    public boolean onTouch(View v, MotionEvent event) {                        if (getScrollY() != 0)                            return true;                        return false;                    }                });            } else if (view instanceof ViewGroup) {                traversalView((ViewGroup) view);            }        }    }}
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