仿Launch的 分页滑动，解决上下左右冲突问题

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);
}
}

}

<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>

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