代码修正

代码/Shop/src/com/stone/shop/scroll/MyScrollLayout.java

@@ -0,0 +1,200 @@
+package com.stone.shop.scroll;
+
+import android.R.bool;
+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.view.View.MeasureSpec;
+import android.widget.Scroller;
+
+public class MyScrollLayout extends ViewGroup {
+
+	private static final String TAG = "ScrollLayout";
+	private VelocityTracker mVelocityTracker; // 用于判断甩动手势
+	private static final int SNAP_VELOCITY = 600;   //X轴速度基值，大于该值时进行切换
+	private Scroller mScroller; // 滑动控制<EFBFBD>?
+	private int mCurScreen;   //当前页面为第几屏
+	private int mDefaultScreen = 0;
+	private float mLastMotionX;
+
+
+	private OnViewChangeListener mOnViewChangeListener;
+
+	public MyScrollLayout(Context context) {
+		super(context);
+		// TODO Auto-generated constructor stub
+		init(context);
+	}
+
+	public MyScrollLayout(Context context, AttributeSet attrs) {
+		super(context, attrs);
+		// TODO Auto-generated constructor stub
+		init(context);
+	}
+
+	private void init(Context context) {
+		mCurScreen = mDefaultScreen;
+		mScroller = new Scroller(context);
+	}
+
+	@Override
+	protected void onLayout(boolean changed, int l, int t, int r, int b) {
+		// TODO Auto-generated method stub
+		
+		Log.e("a", "a");
+		if (changed) {
+			int childLeft = 0;
+			final int childCount = getChildCount();
+			Log.e("count", childCount+"");
+			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) {
+		// TODO Auto-generated method stub
+		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+
+		Log.e("b", "b");
+		final int width = MeasureSpec.getSize(widthMeasureSpec);
+
+		final int count = getChildCount();
+		for (int i = 0; i < count; i++) {
+			getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
+		}
+		
+		scrollTo(mCurScreen * width, 0);
+		
+	}
+
+	public void snapToDestination() {
+		final int screenWidth = getWidth();
+
+		final int destScreen = (getScrollX() + screenWidth / 2) / screenWidth;
+		snapToScreen(destScreen);
+	}
+
+	//使屏幕移动到第whichScreen+1屏
+	public void snapToScreen(int whichScreen) {
+
+		if (getScrollX() != (whichScreen * getWidth())) {
+			final int delta = whichScreen * getWidth() - getScrollX();
+			mScroller.startScroll(getScrollX(), 0, delta, 0,
+					Math.abs(delta) * 2);
+			mCurScreen = whichScreen;
+			invalidate(); 
+
+			if (mOnViewChangeListener != null) {
+				mOnViewChangeListener.OnViewChange(mCurScreen);
+			}
+		}
+	}
+
+	@Override
+	public void computeScroll() {
+		// TODO Auto-generated method stub
+		if (mScroller.computeScrollOffset()) {
+			scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
+			postInvalidate();
+		}
+	}
+
+	@Override
+	public boolean onTouchEvent(MotionEvent event) {
+		// TODO Auto-generated method stub
+
+		final int action = event.getAction();
+		final float x = event.getX();
+		final float y = event.getY();
+
+		switch (action) {
+		case MotionEvent.ACTION_DOWN:
+
+			Log.i("", "onTouchEvent  ACTION_DOWN");
+			if (mVelocityTracker == null) {
+				mVelocityTracker = VelocityTracker.obtain();
+				mVelocityTracker.addMovement(event);
+			}
+			if (!mScroller.isFinished()) {
+				mScroller.abortAnimation();
+			}
+			mLastMotionX = x;
+			break;
+
+		case MotionEvent.ACTION_MOVE:
+			
+			int deltaX = (int) (mLastMotionX - x);
+			if (IsCanMove(deltaX)) {
+				if (mVelocityTracker != null) {
+					mVelocityTracker.addMovement(event);
+				}
+				mLastMotionX = x;
+				//正向或者负向移动，屏幕跟随手指移动
+				scrollBy(deltaX, 0);
+			}
+			break;
+
+		case MotionEvent.ACTION_UP:
+
+			int velocityX = 0;
+			if (mVelocityTracker != null) {
+				mVelocityTracker.addMovement(event);
+				mVelocityTracker.computeCurrentVelocity(1000);
+				//得到X轴方向手指移动速度
+				velocityX = (int) mVelocityTracker.getXVelocity();
+			}
+			//velocityX为正值说明手指向右滑动，为负值说明手指向左滑动
+			if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
+				// Fling enough to move left
+				Log.e(TAG, "snap left");
+				snapToScreen(mCurScreen - 1);
+			} else if (velocityX < -SNAP_VELOCITY
+					&& mCurScreen < getChildCount() - 1) {
+				// Fling enough to move right
+				Log.e(TAG, "snap right");
+				snapToScreen(mCurScreen + 1);
+			} else {
+				snapToDestination();
+			}
+
+			if (mVelocityTracker != null) {
+				mVelocityTracker.recycle();
+				mVelocityTracker = null;
+			}
+
+			break;
+		}
+		return true;
+	}
+
+
+	private boolean IsCanMove(int deltaX) {
+		//deltaX<0说明手指向右划
+		if (getScrollX() <= 0 && deltaX < 0) {
+			return false;
+		}
+		//deltaX>0说明手指向左划
+		if (getScrollX() >= (getChildCount() - 1) * getWidth() && deltaX > 0) {
+			return false;
+		}
+		return true;
+	}
+
+	public void SetOnViewChangeListener(OnViewChangeListener listener) {
+		mOnViewChangeListener = listener;
+	}
+
+}

代码/Shop/src/com/stone/shop/scroll/OnViewChangeListener.java

@@ -0,0 +1,5 @@
+package com.stone.shop.scroll;
+
+public interface OnViewChangeListener {
+	public void OnViewChange(int view);
+}