当滑动到顶部和底部时，实现Item的分离效果的ListView
拉动ListView，Item之间的间距会变大，释放后恢复原样；
自定义属性：
高仿墨迹天气下拉拉伸图片，释放后返回效果
http://blog.csdn.net/wu928320442/article/details/44198157
package cn.tangdada.tangbang.widget;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.BitmapDrawable;
import android.os.Build;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.animation.AccelerateInterpolator;
import android.widget.AbsListView;
import android.widget.ListView;
import cn.tangdada.tangbang.R;
import com.nineoldandroids.view.ViewPropertyAnimator;
/**
* 当滑动到顶部和底部时，实现Item的分离效果。
*
* @author pythoner
*
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public class PullSeparateListView extends ListView
{
/**
* 最大滑动距离
*/
private static final float MAX_DELTAY = 100;
/**
* 分离后恢复的动画时长
*/
private static final long SEPARATE_RECOVER_DURATION = 200;
/**
* 摩擦系数
*/
private static final float FACTOR = 0.25f;
/**
* 按下x的缩放比例
*/
private static final float SCALEX = 1.0f;
/**
* 按下y的缩放比例
*/
private static final float SCALEY = 1.0f;
/**
* 展开全部
*/
private boolean separateAll;
/**
* 到达边界时，滑动的起始位置
*/
private float startY;
/**
* 按下时的View
*/
private View downView;
private int touchSlop;
private boolean separate = false;
private boolean showDownAnim;
/**
* 原始按下位置(在所有Item中的位置)
*/
private int originDownPosition;
/**
* 按下的位置(在屏幕中的位置)
*/
private int downPosition;
/**
* 上次滑动的位置，用于判断方向
*/
private float preY;
private float deltaY;
private boolean reachTop, reachBottom, move;
private OnScrollListener mScrollListener;
public PullSeparateListView(Context context, AttributeSet attrs)
{
super(context, attrs);
TypedArray t = context.obtainStyledAttributes(attrs, R.styleable.PullSeparateListView);
separateAll = t.getBoolean(R.styleable.PullSeparateListView_separate_all, false);
showDownAnim = t.getBoolean(R.styleable.PullSeparateListView_showDownAnim, true);
t.recycle();
init();
}
public PullSeparateListView(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
init();
}
public PullSeparateListView(Context context)
{
super(context);
init();
}
@SuppressWarnings("deprecation")
private void init()
{
// 不知道怎么让divider和selector和Item一起移动，所以去除，需要自己加分割线
this.setDivider(null);
this.setSelector(new BitmapDrawable());
touchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
super.setOnScrollListener(listener);
}
/**
* 是否全部分离
*
* @param separateAll 如果为true,那么全部都会分离。否则的话，如果是顶部下拉，只有点击位置之前的Item会分离</br> 如果是底部上拉，则只有点击位置之后的item会分离。默认为false
*/
public void setSeparateAll(boolean separateAll)
{
this.separateAll = separateAll;
}
public boolean isSeparateAll()
{
return separateAll;
}
/**
* 设置是否显示按下的Item的动画效果
*
* @param showDownAnim 默认为true
*/
public void setShowDownAnim(boolean showDownAnim)
{
this.showDownAnim = showDownAnim;
}
public boolean isShowDownAnim()
{
return showDownAnim;
}
public void setOnScrollListener(OnScrollListener l)
{
mScrollListener = l;
}
// 核心代码
@Override
public boolean dispatchTouchEvent(MotionEvent ev)
{
float currentY = ev.getY();
switch (ev.getAction())
{
case MotionEvent.ACTION_DOWN:
float downX = ev.getX();
float downY = ev.getY();
// 记录按下位置，当isSeparateAll()返回false时，会用到
originDownPosition = pointToPosition((int) downX, (int) downY);
downPosition = originDownPosition - getFirstVisiblePosition();
if (showDownAnim)
{
performDownAnim(downPosition);
}
break;
case MotionEvent.ACTION_MOVE:
// 记录到达顶部或底部时手指的位置
if (!separate)
{
startY = currentY;
}
deltaY = currentY - startY;
// 到达顶部
if (reachTop)
{
if (!separateFromTop(currentY))
{
return super.dispatchTouchEvent(ev);
}
return false;
}
// 到达底部
if (reachBottom)
{
if (!separateFromBottom(currentY))
{
return super.dispatchTouchEvent(ev);
}
return false;
}
preY = currentY;
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
preY = 0;
recoverDownView();
if (separate)
{
separate = false;
recoverSeparate();
// 移动，不响应点击事件
if (move)
{
move = false;
return false;
}
}
break;
}
return super.dispatchTouchEvent(ev);
}
private boolean separateFromTop(float currentY)
{
// 不能放在外部，否则在顶部滑动没有Fling效果
if (deltaY > touchSlop)
{
move = true;
}
separate = true;
// 超过滑动允许的最大距离，则将起始位置向下移
if (deltaY > MAX_DELTAY)
{
startY = currentY - MAX_DELTAY;
// 超过最大距离时，出现overScroll效果//有问题
// return super.dispatchTouchEvent(ev);
}
else if (deltaY < 0)
{ // 为负值时（说明反方向超过了起始位置startY）归0
deltaY = 0;
separate = false;
}
if (deltaY <= MAX_DELTAY)
{
for (int index = 0; index < getChildCount(); index++)
{
View child = getChildAt(index);
int multiple = index;
if (!separateAll)
{
if (index > downPosition)
{
multiple = Math.max(1, downPosition);
}
}
float distance = multiple * deltaY * FACTOR;
child.setTranslationY(distance);
}
// 向分离方向的反方向滑动，但位置还未复原时
if (deltaY != 0 && currentY - preY < 0)
{
return true;
}
// deltaY=0，说明位置已经复原，然后交给父类处理
}
if (deltaY == 0)
{
return false;
}
return true;
}
private boolean separateFromBottom(float currentY)
{
if (Math.abs(deltaY) > touchSlop)
{
move = true;
}
separate = true;
// 超过滑动允许的最大距离，则将起始位置向上移
if (Math.abs(deltaY) > MAX_DELTAY)
{
startY = currentY + MAX_DELTAY;
// 超过最大距离时，出现overScroll效果
// return super.dispatchTouchEvent(ev);
}
else if (deltaY > 0)
{ // 为正值时（说明反方向移动超过起始位置startY），归0
deltaY = 0;
separate = false;
}
if (Math.abs(deltaY) <= MAX_DELTAY)
{
int visibleCount = getChildCount();
for (int inedex = 0; inedex < visibleCount; inedex++)
{
View child = getChildAt(inedex);
int multiple = visibleCount - inedex - 1;
if (!separateAll)
{
if (inedex < downPosition)
{
multiple = Math.max(1, visibleCount - downPosition - 1);
}
}
float distance = multiple * deltaY * FACTOR;
child.setTranslationY(distance);
}
// 向分离方向的反方向滑动，但位置还未复原时
if (deltaY != 0 && currentY - preY > 0)
{
return true;
}
// deltaY=0，说明位置已经复原，然后交给父类处理
if (deltaY == 0)
{
return false;
}
}
return true;
}
/**
* 恢复
*/
private void recoverSeparate()
{
for (int i = 0; i < getChildCount(); i++)
{
View child = getChildAt(i);
ViewPropertyAnimator.animate(child).translationY(0).setDuration(SEPARATE_RECOVER_DURATION).setInterpolator(new AccelerateInterpolator());
}
}
/**
* 按下的动画
*
* @param downPosition 在屏幕中的位置
*/
private void performDownAnim(int downPosition)
{
downView = getChildAt(downPosition);
if (downView != null)
{
ViewPropertyAnimator.animate(downView).scaleX(SCALEX).scaleY(SCALEY).setDuration(50).setInterpolator(new AccelerateInterpolator());
}
}
/**
* 恢复点击的View
*/
private void recoverDownView()
{
if (showDownAnim && downView != null)
{
ViewPropertyAnimator.animate(downView).scaleX(1f).scaleY(1f).setDuration(separate ? SEPARATE_RECOVER_DURATION : 100)
.setInterpolator(new AccelerateInterpolator());
}
}
private OnScrollListener listener = new OnScrollListener()
{
@Override
public void onScrollStateChanged(AbsListView view, int scrollState)
{
if (mScrollListener != null)
{
mScrollListener.onScrollStateChanged(view, scrollState);
}
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
{
if (mScrollListener != null)
{
mScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
}
// 是否到达顶部
if (firstVisibleItem == 0)
{
View firstView = getChildAt(firstVisibleItem);
if (firstView != null && (firstView.getTop() + getPaddingTop()) >= 0)
{
downPosition = originDownPosition;
reachTop = true;
}
else
{
reachTop = false;
}
}
else
{
reachTop = false;
}
// 是否到达底部
if (firstVisibleItem + visibleItemCount == getCount())
{
View lastView = getChildAt(visibleItemCount - 1);
if (lastView != null && (lastView.getBottom() + getPaddingBottom()) <= getHeight() && getCount() > getChildCount())
{
downPosition = originDownPosition - firstVisibleItem;
reachBottom = true;
}
else
{
reachBottom = false;
}
}
else
{
reachBottom = false;
}
}
};
/**
* 是否到达顶部
*
* @return
*/
@Deprecated
protected boolean isReachTopBound()
{
int firstVisPos = getFirstVisiblePosition();
if (firstVisPos == 0)
{
View firstView = getChildAt(firstVisPos);
if (firstView != null && firstView.getTop() >= 0)
{
return true;
}
else
{
return false;
}
}
return false;
}
/**
* 是否到达底部
*
* @return
*/
@Deprecated
protected boolean isReachBottomBound()
{
int lastVisPos = getLastVisiblePosition();
if (lastVisPos == getCount() - 1)
{
View lastView = getChildAt(getChildCount() - 1);
if (lastView != null && lastView.getBottom() <= getHeight() && getCount() > getChildCount())
{
return true;
}
else
{
return false;
}
}
return false;
}
}
自定义属性：
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="PullSeparateListView">
<attr name="separate_all" format="boolean"/>
<attr name="showDownAnim" format="boolean"/>
</declare-styleable>
</resources>
高仿墨迹天气下拉拉伸图片，释放后返回效果
http://blog.csdn.net/wu928320442/article/details/44198157