package com.zhulin.android.atools;

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.ViewGroup;
import android.view.animation.Interpolator;
import android.widget.Scroller;
import android.widget.Toast;

public class VerticalPager extends ViewGroup{

	private Scroller mScroller;
	private Context mContext;
	public VerticalPager(Context context, AttributeSet attrs) {
		super(context, attrs);
		this.mContext=context;
		mScroller=new Scroller(context);
//		mScroller=new Scroller(mContext, new Interpolator() {
//			
//			@Override
//			public float getInterpolation(float input) {
//				return 300;
//			}
//		});
		
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		int totalHeight=0;
		int count=getChildCount();

		for(int i=0;i<count;i++){
			View childView=getChildAt(i);

			//			int measureHeight=childView.getMeasuredHeight();
			//			int measureWidth=childView.getMeasuredWidth();

			childView.layout(l, totalHeight, r, totalHeight+b);

			totalHeight+=b;
		}
	}

	private VelocityTracker mVelocityTracker;

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		int width=MeasureSpec.getSize(widthMeasureSpec);
		int height=MeasureSpec.getSize(heightMeasureSpec);


		int count=getChildCount();
		for(int i=0;i<count;i++){
			getChildAt(i).measure(width, height);
		}
		setMeasuredDimension(width, height);
	}


	private int mLastMotionY;
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		if(mVelocityTracker==null){
			mVelocityTracker=VelocityTracker.obtain();
		}
		mVelocityTracker.addMovement(event);

		int action=event.getAction();

		float y=event.getY();

		switch(action){
		case MotionEvent.ACTION_DOWN:
			if(!mScroller.isFinished()){
				mScroller.abortAnimation();
			}
			mLastMotionY=(int) y;
			
			Log.d("montion", ""+getScrollY());
			break;
		case MotionEvent.ACTION_MOVE:
			int deltaY=(int) (mLastMotionY-y);
				scrollBy(0,deltaY);
			//mScroller.startScroll(0, getScrollY(), 0, deltaY);
			invalidate();
			
			mLastMotionY=(int) y;
			break;
		case MotionEvent.ACTION_UP:
			if(mVelocityTracker!=null){
				mVelocityTracker.recycle();
				mVelocityTracker=null;
			}
			
			if(getScrollY()<0){
				mScroller.startScroll(0, -400, 0, 400);
			}else if(getScrollY()>(getHeight()*(getChildCount()-1))){
				View lastView=getChildAt(getChildCount()-1);
				
				mScroller.startScroll(0,lastView.getTop()+300, 0, -300);
			}else{
				int position=getScrollY()/getHeight();
				int mod=getScrollY()%getHeight();
				
				
				if(mod>getHeight()/3){
					View positionView=getChildAt(position+1);
					mScroller.startScroll(0, positionView.getTop()-300, 0, +300);
				}else{
					View positionView=getChildAt(position);
					mScroller.startScroll(0, positionView.getTop()+300, 0, -300);
				}
				
				
			}
			invalidate();
			break;
//		case MotionEvent.ACTION_MASK:
//			if(getScrollY()<0){
//				mScroller.startScroll(0, 0, 0, 0);
//			}else if(getScrollY()>(getHeight()*(getChildCount()-1)){
//			}
//			invalidate();
//			break;
		}

		return true;
	}
	
	@Override
	public void computeScroll() {
		super.computeScroll();
		
		if(mScroller.computeScrollOffset()){
			scrollTo(0, mScroller.getCurrY());
		}else{
			
		}
	}

}

xml布局

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <com.zhulin.android.atools.VerticalPager
        android:id="@+id/vertyPager1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

        <TextView
            android:background="@drawable/a1"
            android:id="@+id/textView1"
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:text="TextView1111" />

        <TextView
             android:background="@drawable/a2"
            android:id="@+id/textView2"
            android:layout_width="fill_parent"
            android:layout_height="100dp"
            android:text="TextView2222" />
        
         <TextView
             android:background="@drawable/a3"
            android:id="@+id/textView3"
            android:layout_width="fill_parent"
            android:layout_height="100dp"
            android:text="TextView2222" />
         
          <TextView
             android:background="@drawable/a4"
            android:id="@+id/textView4"
            android:layout_width="fill_parent"
            android:layout_height="100dp"
            android:text="TextView2222" />
    </com.zhulin.android.atools.VertyPager>

</LinearLayout>

坚向的ViewPager，上下滑动的组件，android上下滑动 VerticalPager