SlidingFinishLayout.java

package cn.edu.chd.view;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.RelativeLayout;
import android.widget.ScrollView;
import android.widget.Scroller;

/**
 * @author Rowand jj
 *����ɾ��view��Ч��
 */
public class SlidingFinishLayout extends RelativeLayout implements
		OnTouchListener
{
	/**
	 * SildingFinishLayout���ֵĸ�����
	 */
	private ViewGroup mParentView;
	/**
	 * �������߼���View
	 */
	private View touchView;
	/**
	 * ������������
	 */
	private int mTouchSlop;
	/**
	 * ���µ��X����
	 */
	private int downX;
	/**
	 * ���µ��Y����
	 */
	private int downY;
	/**
	 * ��ʱ�洢X����
	 */
	private int tempX;
	/**
	 * ������
	 */
	private Scroller mScroller;
	/**
	 * SildingFinishLayout�Ŀ��
	 */
	private int viewWidth;
	/**
	 * ��¼�Ƿ����ڻ���
	 */
	private boolean isSliding;

	private OnSlidingFinishListener onSlidingFinishListener;
	private boolean isFinish;

	public SlidingFinishLayout(Context context, AttributeSet attrs)
	{
		this(context, attrs, 0);
	}

	public SlidingFinishLayout(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
		// ��ȡ��������С����
		mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
		// ����Scroller
		mScroller = new Scroller(context);
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b)
	{
		super.onLayout(changed, l, t, r, b);
		if (changed)
		{
			// ��ȡSildingFinishLayout���ڲ��ֵĸ�����
			mParentView = (ViewGroup) this.getParent();
			viewWidth = this.getWidth();
		}
	}

	/**
	 * ����OnSlidingFinishListener, ��onSlidingFinish()������finish Activity
	 * 
	 * @param OnSlidingFinishListener
	 */
	public void setOnSlidingFinishListener(
			OnSlidingFinishListener onSlidingFinishListener)
	{
		this.onSlidingFinishListener = onSlidingFinishListener;
	}

	/**
	 * ����Touch��View
	 * 
	 * @param touchView
	 */
	public void setTouchView(View touchView)
	{
		this.touchView = touchView;
		touchView.setOnTouchListener(this);
	}

	public View getTouchView()
	{
		return touchView;
	}

	/**
	 * ����������
	 */
	private void scrollRight()
	{
		final int delta = (viewWidth + mParentView.getScrollX());
		// ����startScroll����������һЩ�����IJ�����������computeScroll()�����е���scrollTo������item
		mScroller.startScroll(mParentView.getScrollX(), 0, -delta + 1, 0,
				Math.abs(delta));
		postInvalidate();
	}

	/**
	 * ��������ʼλ��
	 */
	private void scrollOrigin()
	{
		int delta = mParentView.getScrollX();
		mScroller.startScroll(mParentView.getScrollX(), 0, -delta, 0,
				Math.abs(delta));
		postInvalidate();
	}

	/**
	 * touch��View�Ƿ���AbsListView�� ����ListView, GridView��������
	 * 
	 * @return
	 */
	private boolean isTouchOnAbsListView()
	{
		return touchView instanceof AbsListView ? true : false;
	}

	/**
	 * touch��view�Ƿ���ScrollView����������
	 * 
	 * @return
	 */
	private boolean isTouchOnScrollView()
	{
		return touchView instanceof ScrollView ? true : false;
	}

	@Override
	public boolean onTouch(View v, MotionEvent event)
	{
		switch (event.getAction())
		{
		case MotionEvent.ACTION_DOWN:
			downX = tempX = (int) event.getRawX();
			downY = (int) event.getRawY();
			break;
		case MotionEvent.ACTION_MOVE:
			int moveX = (int) event.getRawX();
			int deltaX = tempX - moveX;
			tempX = moveX;
			if (Math.abs(moveX - downX) > mTouchSlop
					&& Math.abs((int) event.getRawY() - downY) < mTouchSlop)
			{
				isSliding = true;

				// ��touchView��AbsListView��
				// ����ָ������ȡ��item�ĵ���¼�����Ȼ���ǻ���Ҳ������item����¼��ķ���
				if (isTouchOnAbsListView())
				{
					MotionEvent cancelEvent = MotionEvent.obtain(event);
					cancelEvent
							.setAction(MotionEvent.ACTION_CANCEL
									| (event.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT));
					v.onTouchEvent(cancelEvent);
				}

			}

			if (moveX - downX >= 0 && isSliding)
			{
				mParentView.scrollBy(deltaX, 0);

				// �����ڻ���������ListView ScrollView���Լ��Ļ����¼�
				if (isTouchOnScrollView() || isTouchOnAbsListView())
				{
					return true;
				}
			}
			break;
		case MotionEvent.ACTION_UP:
			isSliding = false;
			if (mParentView.getScrollX() <= -viewWidth / 2)
			{
				isFinish = true;
				scrollRight();
			} else
			{
				scrollOrigin();
				isFinish = false;
			}
			break;
		}

		// ����touch��view��AbsListView����ScrollView ���Ǵ����������Լ����߼�֮��
		// �ٽ���AbsListView, ScrollView�Լ��������Լ����߼�
		if (isTouchOnScrollView() || isTouchOnAbsListView())
		{
			return v.onTouchEvent(event);
		}

		// ���������ֱ�ӷ���true
		return true;
	}

	@Override
	public void computeScroll()
	{// ��дview��computeScroll
		// ����startScroll��ʱ��scroller.computeScrollOffset()����true��
		if (mScroller.computeScrollOffset())
		{
			mParentView.scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
			postInvalidate();

			if (mScroller.isFinished())
			{

				if (onSlidingFinishListener != null && isFinish)
				{
					onSlidingFinishListener.onSlidingFinish();
				}
			}
		}
	}

	public interface OnSlidingFinishListener
	{
		public void onSlidingFinish();
	}

}