仿Launch的 分页滑动，解决上下左右冲突问题

先上效果图：

public class CVScrollLayout extends ViewGroup {

	private static final String TAG = "ScrollLayout";
	private Scroller mScroller;
	private VelocityTracker mVelocityTracker;

	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;
	private float mLastMotionY;

	public CVScrollLayout(Context context, AttributeSet attrs) {
		this(context, attrs, 0);
		// TODO Auto-generated constructor stub
	}

	public CVScrollLayout(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		// 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) {
		// TODO Auto-generated method stub
		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);
		}
		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;
			onScreenChangeListener.onScreenChange(mCurScreen);
			invalidate(); // Redraw the layout
		}
	}

	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() {
		// 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

		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;
			mLastMotionY = y;
			break;

		case MotionEvent.ACTION_MOVE:
			int deltaX = (int) (mLastMotionX - x);
			int deltaY = (int)(mLastMotionY - y);
			mLastMotionX = x;
			mLastMotionY = y;
			if(Math.abs(deltaX) > Math.abs(deltaY)){
				scrollBy(deltaX, 0);
			}
			break;

		case MotionEvent.ACTION_UP:
			// if (mTouchState == TOUCH_STATE_SCROLLING) {
			final VelocityTracker velocityTracker = mVelocityTracker;
			velocityTracker.computeCurrentVelocity(1000);
			int velocityX = (int) velocityTracker.getXVelocity();

			if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
				// Fling enough to move left
				// onScreenChangeListener.onScreenChange(mCurScreen - 1);
				snapToScreen(mCurScreen - 1);
			} else if (velocityX < -SNAP_VELOCITY
					&& mCurScreen < getChildCount() - 1) {
				// Fling enough to move 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 ev) {
		// TODO Auto-generated method stub
		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) {
		case MotionEvent.ACTION_MOVE:
			int deltaX = (int)(mLastMotionX - x);
			int deltaY = (int)(mLastMotionY - y);
			final int xDiff = (int) Math.abs(mLastMotionX - x);
			
			if (xDiff > mTouchSlop && Math.abs(deltaX) > Math.abs(deltaY)) {
				mTouchState = TOUCH_STATE_SCROLLING;
			}else {
				mTouchState = TOUCH_STATE_REST;
			}
			break;

		case MotionEvent.ACTION_DOWN:
			mLastMotionX = x;
			mLastMotionY = y;
			mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
					: TOUCH_STATE_SCROLLING;
			break;

		case MotionEvent.ACTION_CANCEL:
		case MotionEvent.ACTION_UP:
			mTouchState = TOUCH_STATE_REST;
			break;
		}

		return mTouchState != TOUCH_STATE_REST;
	}

	// 监听页面变动
	public interface OnScreenChangeListener {
		void onScreenChange(int currentIndex);
	}

	private OnScreenChangeListener onScreenChangeListener;

	public void setOnScreenChangeListener(
			OnScreenChangeListener onScreenChangeListener) {
		this.onScreenChangeListener = onScreenChangeListener;
	}

}

public class CVPageControlView extends LinearLayout {

	private Context context;
	private int count;

	public CVPageControlView(Context context) {
		super(context);
		this.context = context;
	}

	public CVPageControlView(Context context, AttributeSet attrs) {
		super(context, attrs);
		this.context = context;
	}

	public void bindScrollLayout(CVScrollLayout scrollLayout) {
		this.count = scrollLayout.getChildCount();
		// 初始化第一屏
		generatePageControl(0);
		scrollLayout.setOnScreenChangeListener(new OnScreenChangeListener() {

			@Override
			public void onScreenChange(int currentIndex) {

				generatePageControl(currentIndex);
			}
		});
	}

	public void generatePageControl(int currentIndex) {
		this.removeAllViews();
		for (int i = 0; i < this.count; i++) {
			ImageView imageView = new ImageView(context);
			if (i == currentIndex) {
				imageView.setImageResource(R.drawable.page_indicator_focused);
			} else {
				imageView.setImageResource(R.drawable.page_indicator);
			}
			this.addView(imageView);
		}
	}

}

布局文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <com.zoeice.scrolllayout.CVScrollLayout
        android:id="@+id/scrollControl"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#ffe00000" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#ff00e000" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#ff0000e0" />
    </com.zoeice.scrolllayout.CVScrollLayout>

    <com.zoeice.scrolllayout.CVPageControlView
        android:id="@+id/pageControl"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="5dip" >
    </com.zoeice.scrolllayout.CVPageControlView>

</RelativeLayout>

调用方法：

CVScrollLayout sl = (CVScrollLayout) findViewById(R.id.scrollControl);
		CVPageControlView pageControlView = (CVPageControlView) findViewById(R.id.pageControl);
		
		pageControlView.bindScrollLayout(sl);//绑定控件
		
		sl.setToScreen(0);//默认第一页
		pageControlView.generatePageControl(0);//默认第一个点