Android 类似QQ微信WebView的上拉下拉弹跳效果

package com.admin.baselibrary; import android.content.Context; import android.content.res.TypedArray; import android.os.Build; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.ViewCompat; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.widget.AbsListView; import android.widget.FrameLayout; /** * github:https://github.com/HomHomLin/SlidingLayout * Created by Linhh on 16/4/12. */ public class SlidingLayout extends FrameLayout { private int mTouchSlop;//系统允许最小的滑动判断值 private int mBackgroundViewLayoutId = 0; private View mBackgroundView;//背景View private View mTargetView;//正面View private boolean mIsBeingDragged; private float mInitialDownY; private float mInitialMotionY; private float mLastMotionY; private int mActivePointerId = INVALID_POINTER; private float mSlidingOffset = 0.5F;//滑动阻力系数 private static final int RESET_DURATION = 200; private static final int SMOOTH_DURATION = 1000; public static final int SLIDING_MODE_BOTH = 0; public static final int SLIDING_MODE_TOP = 1; public static final int SLIDING_MODE_BOTTOM = 2; public static final int SLIDING_POINTER_MODE_ONE = 0; public static final int SLIDING_POINTER_MODE_MORE = 1; private int mSlidingMode = SLIDING_MODE_BOTH; private int mSlidingPointerMode = SLIDING_POINTER_MODE_MORE; private static final int INVALID_POINTER = -1; private SlidingListener mSlidingListener; public static final int STATE_SLIDING = 2; public static final int STATE_IDLE = 1; private int mSlidingTopMaxDistance = SLIDING_DISTANCE_UNDEFINED; public static final int SLIDING_DISTANCE_UNDEFINED = -1; private OnTouchListener mDelegateTouchListener; public interface SlidingListener { //不能操作繁重的任务在这里 public void onSlidingOffset(View view, float delta); public void onSlidingStateChange(View view, int state); public void onSlidingChangePointer(View view, int pointerId); } public SlidingLayout(Context context) { this(context, null); } public SlidingLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); } public SlidingLayout(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context, attrs); } private void init(Context context, AttributeSet attrs) { TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SlidingLayout); mBackgroundViewLayoutId = a.getResourceId(R.styleable.SlidingLayout_background_view, mBackgroundViewLayoutId); mSlidingMode = a.getInteger(R.styleable.SlidingLayout_sliding_mode, SLIDING_MODE_BOTH); mSlidingPointerMode = a.getInteger(R.styleable.SlidingLayout_sliding_pointer_mode, SLIDING_POINTER_MODE_MORE); mSlidingTopMaxDistance = a.getDimensionPixelSize(R.styleable.SlidingLayout_top_max, SLIDING_DISTANCE_UNDEFINED); a.recycle(); if (mBackgroundViewLayoutId != 0) { View view = View.inflate(getContext(), mBackgroundViewLayoutId, null); setBackgroundView(view); } mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop(); } public void setBackgroundView(View view) { if (mBackgroundView != null) { this.removeView(mBackgroundView); } mBackgroundView = view; this.addView(view, 0); } public View getBackgroundView() { return this.mBackgroundView; } public void setSlidingDistance(int distance) { this.mSlidingTopMaxDistance = distance; } public int setSlidingDistance() { return this.mSlidingTopMaxDistance; } /** * 获得滑动幅度 * * @return */ public float getSlidingOffset() { return this.mSlidingOffset; } /** * 设置滑动幅度 * * @param slidingOffset */ public void setSlidingOffset(float slidingOffset) { this.mSlidingOffset = slidingOffset; } public void setSlidingListener(SlidingListener slidingListener) { this.mSlidingListener = slidingListener; } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); //实际上整个layout只能存在一个背景和一个前景才有用途 // if(getChildCount() > 2){ // // } if (getChildCount() == 0) { return; } if (mTargetView == null) { ensureTarget(); } if (mTargetView == null) { return; } } private void ensureTarget() { if (mTargetView == null) { mTargetView = getChildAt(getChildCount() - 1); } } public void setTargetView(View view) { if (mTargetView != null) { this.removeView(mTargetView); } mTargetView = view; this.addView(view); } @Override public void setOnTouchListener(OnTouchListener l) { // super.setOnTouchListener(l); mDelegateTouchListener = l; } public View getTargetView() { return this.mTargetView; } public float getSlidingDistance() { return getInstrument().getTranslationY(getTargetView()); } public Instrument getInstrument() { return Instrument.getInstance(); } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { ensureTarget(); final int action = MotionEventCompat.getActionMasked(ev); //判断拦截 switch (action) { case MotionEvent.ACTION_DOWN: // Log.i("onInterceptTouchEvent", "down"); mActivePointerId = MotionEventCompat.getPointerId(ev, 0); mIsBeingDragged = false; final float initialDownY = getMotionEventY(ev, mActivePointerId); if (initialDownY == -1) { return false; } mInitialDownY = initialDownY; break; case MotionEvent.ACTION_MOVE: if (mActivePointerId == INVALID_POINTER) { // Log.e(LOG_TAG, "Got ACTION_MOVE event but don't have an active pointer id."); return false; } final float y = getMotionEventY(ev, mActivePointerId); if (y == -1) { return false; } if (y > mInitialDownY) { //判断是否是上拉操作 final float yDiff = y - mInitialDownY; if (yDiff > mTouchSlop && !mIsBeingDragged && !canChildScrollUp()) { mInitialMotionY = mInitialDownY + mTouchSlop; mLastMotionY = mInitialMotionY; mIsBeingDragged = true; } } else if (y < mInitialDownY) { //判断是否是下拉操作 final float yDiff = mInitialDownY - y; if (yDiff > mTouchSlop && !mIsBeingDragged && !canChildScrollDown()) { mInitialMotionY = mInitialDownY + mTouchSlop; mLastMotionY = mInitialMotionY; mIsBeingDragged = true; } } break; case MotionEventCompat.ACTION_POINTER_UP: break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: // Log.i("onInterceptTouchEvent", "up"); mIsBeingDragged = false; mActiv