继承Linearlayout的Viewgroup可以左右流畅滑动切换

package com.TestProject.MainActivity; import java.util.ArrayList; import java.util.List; import java.util.Map; import android.content.Context; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.ViewConfiguration; import android.view.View.MeasureSpec; import android.widget.LinearLayout; import android.widget.Scroller; /** * @author chieh * * 2014-6-4 */ public class test extends LinearLayout { private static final String TAG = "ScrollLayout"; private Scroller mScroller; private VelocityTracker mVelocityTracker; public 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 static final int COMPUTE_MIN_DIFF = 30; private int mTouchState = TOUCH_STATE_REST; private int mTouchSlop; private float mLastMotionX; private float mLastMotionY; public List<Map<String, String>> projectList = new ArrayList<Map<String, String>>(); public test(Context context, AttributeSet attrs) { super(context, attrs); // TODO Auto-generated constructor stub mScroller = new Scroller(context); mCurScreen = mDefaultScreen; mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop(); } // @Override // protected void onLayout(boolean changed, int l, int t, int r, int b) { // // 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; // } // } // } // } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 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.i(TAG, "moving to screen "+mCurScreen); scrollTo(mCurScreen * width, 0); } /** * According to the position of current layout * scroll to the destination page. */ public void snapToDestination() { final int screenWidth = getWidth(); final int destScreen = (getScrollX()+ screenWidth/2)/screenWidth; snapToScreen(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(); mScroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta)*2); mCurScreen = whichScreen; } } 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; } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); postInvalidate(); } } @Override public boolean onTouchEvent(MotionEvent event) { 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: if (!mScroller.isFinished()){ mScroller.abortAnimation(); } mLastMotionX = x; break; case MotionEvent.ACTION_MOVE: int deltaX = (int)(mLastMotionX - x); mLastMotionX = x; scrollBy(deltaX, 0); break; case MotionEvent.ACTION_UP: Log.i(TAG, "event : up"); // if (mTouchState == TOUCH_STATE_SCROLLING) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000); int velocityX = (int) velocityTracker.getXVelocity(); Log.i(TAG, "velocityX:"+velocityX); if (velocityX > SNAP_VELOCITY && mCurScreen > 0) { // Fling enough to move left onScreenChangeListener.onScreenChange(mCurScreen - 1); Log.i(TAG, "snap left"); snapToScreen(mCurScreen - 1); } else if (velocityX < -SNAP_VELOCITY && mCurScreen < getChildCount() - 1) { // Fling enough to move right Log.i(TAG, "snap right"); onScreenChangeListener.onScreenChange(mCurScreen + 1); snapToScreen(mCurScreen + 1); } else { snapToDestination(); } if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } // } mTouchState = TOUCH_STATE_REST; break; case MotionEvent.ACTION_CANCEL: mTouchState = TOUCH_STATE_REST; break; } return true; } @Override public boolean onInterceptTouchEvent(MotionEvent event) { super.onInterceptTouchEvent(event); if (MotionEventUtil.getPointerCount(event) > 1) { // マルチタッチ時にスクロールはしないので判定終了 requestDisallowInterceptTouchEvent(true); return false; } // onTouch()のために加速度の計算を始める if (event.getAction() == MotionEvent.ACTION_DOWN) { //mPrevX = event.getX(); mLastMotionX = event.getX(); mLastMotionY = event.getY(); } // スクロールなのか、コンテンツにアクセスなのか判定する float diffX = Math.abs(event.getX() - mLastMotionX); float diffY = Math.abs(event.getY() - mLastMotionY); if (!mScroller.isFinished()) { // スクロール中なので、インターセプトする mScroller.abortAnimation(); return true; } else if (Math.max(diffX, diffY) < COMPUTE_MIN_DIFF) { // まだ判定できる移動距離に達していないので見送り return false; } else if (diffX > (diffY * 2)) { // 横スクロールなので、インターセプトする mLastMotionX = event.getX(); mLastMotionY = event.getY();