左右滑动翻页Glide_ActivityGroup

package com.lp.scroll; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.Scroller; /** * 仿Launcher中的WorkSapce，可以左右滑动切换屏幕的类 */ public class ScrollLayout extends ViewGroup { private static final String TAG = "ScrollLayout"; private Scroller mScroller; /** * 数度检测 */ private VelocityTracker mVelocityTracker; /** * 当前页面号 */ private int mCurScreen; private int mDefaultScreen = 0; private static final int TOUCH_STATE_REST = 0; private static final int TOUCH_STATE_SCROLLING = 1; private static final int SNAP_VELOCITY = 600; private int mTouchState = TOUCH_STATE_REST; private int mTouchSlop; private float mLastMotionX; /** * 用于返回当前页号，和需要移动到的页号 */ private OnScreenChanageCallBack occb; public ScrollLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); } public ScrollLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); mScroller = new Scroller(context); // 默认显示第一屏 mCurScreen = mDefaultScreen; mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop(); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { Log.e(TAG, "onLayout" + "--changed:" + changed+"----"); // if (changed) { int childLeft = 0; final int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { final View childView = getChildAt(i); if (childView.getVisibility() != View.GONE) { final int childWidth = childView.getMeasuredWidth(); childView.layout(childLeft, 0, childLeft + childWidth, childView.getMeasuredHeight()); childLeft += childWidth; // 很明显 0 - 320 | 320 - 640 | 640 - 960 ...（假设屏幕宽320） } } // } } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { Log.e(TAG, "onMeasure"); super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int width = MeasureSpec.getSize(widthMeasureSpec); // final int widthMode = MeasureSpec.getMode(widthMeasureSpec); // if (widthMode != MeasureSpec.EXACTLY) { // throw new IllegalStateException( // "ScrollLayout only canmCurScreen run at EXACTLY mode!"); // } // // final int heightMode = MeasureSpec.getMode(heightMeasureSpec); // if (heightMode != MeasureSpec.EXACTLY) { // throw new IllegalStateException( // "ScrollLayout only can run at EXACTLY mode!"); // } // The children are given the same width and height as the scrollLayout final int count = getChildCount(); for (int i = 0; i < count; i++) { getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); } // Log.e(TAG, "moving to screen "+mCurScreen); // x坐标 y坐标 // 移动到第几屏 scrollTo(mCurScreen * width, 0); } /** * According to the position of current layout scroll to the destination * page. 判断滑动的位置 如果大于当前屏中间的位置 则换屏 否则 仍然是这个屏 getScrollX x方向的偏移量 */ public void snapToDestination() { final int screenWidth = getWidth(); final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth; if (occb != null) { occb.glideNext(destScreen); } } public void snapToScreen(int whichScreen) { // get the valid layout page whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); if (getScrollX() != (whichScreen * getWidth())) { final int delta = whichScreen * getWidth() - getScrollX(); Log.e(TAG, "glibeSpeed:---------------------"+Math.abs(delta) * 2); // 开始滚动 // x，y，x方向移动量，y方向移动量，滚动持续时间，负数往左滚 int speed=Math.abs(delta)*2;//根据页面的距离来确定动画时间 if(speed>960){ speed=350; } mScroller.startScroll(getScrollX(), 0, delta, 0, speed); mCurScreen = whichScreen; if (occb != null) { occb.onScreenChanage(mCurScreen); } invalidate(); // Redraw the layout } } public void setOnScreenChangeCallBack(OnScreenChanageCallBack occb) { this.occb = occb; } public void setToScreen(int whichScreen) { whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1)); mCurScreen = whichScreen; scrollTo(whichScreen * getWidth(), 0); } public int getCurScreen() { return mCurScreen; } public int getScreenCount() { return getChildCount(); } // 只有当前LAYOUT中的某个CHILD导致SCROLL发生滚动，才会致使自己的COMPUTESCROLL被调用 @Override public void computeScroll() { // TODO Auto-generated method stub Log.e(TAG, "computeScroll"); // 如果返回true，表示动画还没有结束 // 因为前面startScroll，所以只有在startScroll完成时 才会为false if (mScroller.computeScrollOffset()) { Log.e(TAG, mScroller.getCurrX() + "======" + mScroller.getCurrY()); // 产生了动画效果 每次滚动一点 scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub Log.e(TAG, "onTouchEvent start"); /*速度检测*/ if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(event); final int action = event.getAction(); final float x = event.getX(); final float y = event.getY(); switch (action) { case MotionEvent.ACTION_DOWN://按下 Log.e(TAG, "event down! " + mScroller.isFinished()); // 如果屏幕的滚动动画没有结束 你就按下了 就结束动画 if (!mScroller.isFinished()) { mScroller.abortAnimation(); } mLastMotionX = x; break; case MotionEvent.ACTION_MOVE://移动 int deltaX = (int) (mLastMotionX - x); //如果当前为第0页则不能右滑，deltaX<0代表向右滑 if(mCurScreen==0&&deltaX<0){ break; } //如果当前为第末页则不能左滑 else if(mCurScreen==(getChildCount() - 1)&&deltaX>0){ break; } Log.e(TAG, "event move!"); // 取得偏移量 Log.e(TAG, "detaX: " + deltaX); mLastMotionX = x; // x方向的偏移量 y方向的偏移量 scrollBy(deltaX, 0); break; case MotionEvent.ACTION_UP://放开 Log.e(TAG, "event : up"); final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000); int velocityX = (int) velocityTracker.getXVelocity(); Log.e(TAG, "velocityX:" + velocityX); //如果向右滑动速度大于默认速度，且大于0页 if (velocityX > SNAP_VELOCITY && mCurScreen > 0) { // Fling enough to move left Log.e(TAG, "snap left"); if (occb != null) { //滑动到上一页 occb.glideNext(mCurScreen - 1); } } //如果向左滑动速度大于默认速度，且小于末页，滑到下一页 else if (velocityX < -SNAP_VELOCITY && mCurScreen < getChildCount() - 1) { // Fling enough to move right Log.e(TAG, "snap right"); if (occb != null) { occb.glideNext(mCurScreen + 1); } } else { //慢慢滑到大于1/2宽度则切换页号 snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } mTouchState = TOUCH_STATE_REST; break; case MotionEvent.ACTION_CANCEL: mTouchState = TOUCH_STATE_REST; break; } return true; } // 这个感觉没什么作用 不管true还是false 都是会执行onTouchEvent的 因为子view里面onTouchEvent返回false了 @Override public boolean onInterceptTouchEvent(MotionEvent ev) { // TODO Auto-generated method stub Log.e(TAG, "onInterceptTouchEvent-slop:" + mTouchSlop); final int action = ev.getAction(); if ((action == MotionEvent.ACTION_MOVE) && (mTouchState != TOUCH_STATE_REST)) { return true; } final float x = ev.getX(); final float y = ev.getY(); switch (action)