ViewDragHelper

import android.content.Context;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;

/**
* Created by Administrator on 2015/12/17.
*/
public class DragViewGroup extends FrameLayout {

private ViewDragHelper mViewDragHelper;
private View mMenuView,mMainView;
private int mWtdth;

public DragViewGroup(Context context) {
super(context);
initView();
}

public DragViewGroup(Context context, AttributeSet attrs) {
super(context, attrs);
initView();
}

public DragViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initView();
}

@Override
protected void onFinishInflate() {
super.onFinishInflate();
mMenuView = getChildAt(0);
mMainView = getChildAt(1);
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mWtdth = mMenuView.getMeasuredWidth();
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
return mViewDragHelper.shouldInterceptTouchEvent(ev);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
mViewDragHelper.processTouchEvent(event);
return true;
}

public void initView(){
mViewDragHelper = ViewDragHelper.create(this,callback);
}

private ViewDragHelper.Callback callback = new ViewDragHelper.Callback() {
@Override
public boolean tryCaptureView(View child, int pointerId) {
return mMainView == child;
}

@Override
public int clampViewPositionVertical(View child, int top, int dy) {
return 0;
}

@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
return left;
}

@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
super.onViewReleased(releasedChild, xvel, yvel);
if(mMainView.getLeft() < 500){
mViewDragHelper.smoothSlideViewTo(mMainView,0,0);
ViewCompat.postInvalidateOnAnimation(DragViewGroup.this);
}else{
mViewDragHelper.smoothSlideViewTo(mMainView,300,0);
ViewCompat.postInvalidateOnAnimation(DragViewGroup.this);
}
}
};

@Override
public void computeScroll() {
if(mViewDragHelper.continueSettling(true)){
ViewCompat.postInvalidateOnAnimation(this);
}
}
}