分组列表项目源码地址：
http://code.google.com/p/android-section-list/
android中listiew仿组向上滚动特效 原文地址：
http://www.cnblogs.com/xiaoQLu/archive/2011/12/20/2293732.html
非常感谢 kylin17 和 哟一嗨 同学发现的bug，确实存在此问题，已修正
MySectionIndexer.java中
public
int
getPositionForSection(
int
section)方法第一个判断有误，应该为大于等于，已修改，源码重新上传
手机qq上有这样一个特效：当前分组的好友，向上滚动时，在顶部会出现一个透明的框，当下一个分组到达时，会把上一个分组慢慢顶上去，觉得这个特效蛮有意思，就研究了一下，android自带的通讯录分组就有这个特效，这里是自己仿写的一个，部分源码从通讯录中扣出来的
实现原理：
前提条件，假设所有的数据已经分好组
1.listview中每一个item都默认有一个分组标签，但是只显示此分组下面的第一个，其他的默认不显示
2.滚动的时候，判断每一个分组的状态，是向上滚动，还是完全显示，或者隐藏，主要是取当前item所在的分组跟(下一个分组-1=当前分组)相比，如果相等，说明是向上流动，否则是隐藏
3.获取当前分组的状态后，就可以放置分组的位置了，这里使用view.layout(int left,int top,int rigth,int bottom) ，其他left是0，right是分组标签的长度，top和bottom是需要计算的，用ViewGroup.getChileAt(0)获取listview中第一个孩子的view，然后用bottom=view.getBottom获取底部距离父窗口的位置，最后得到两者之差y=bottom-标题框的高度，用这个差就可以得出顶部和底部的位置，就是top和bottom的值。
关键类解析 ：
PinnedHeaderListView.java 这个是实现listview分组的关键，当然布局文件中的listview也要使用这个类，里面有个接口，adapter要实现此接口，是滚动时回调用，其中getPinnedHeaderState()是用来分组标签状态的，
它的3种状态都在此接口中定义，configurePinnedHeader()是用来设置分组标签的标题，也是相当于组中的组名，此类中的configHeaderView()就是放置分组使用的，结合上面的分析跟这个方法研究这个类
/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*
http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package
com.demo.sectionlistview;
import
android.content.Context;
import
android.graphics.Canvas;
import
android.util.AttributeSet;
import
android.view.View;
import
android.widget.ListAdapter;
import
android.widget.ListView;
/**
* A ListView that maintains a header pinned at the top of the list. The
* pinned header can be pushed up and dissolved as needed.
*/
public
class
PinnedHeaderListView
extends
ListView {
/**
* Adapter interface. The list adapter must implement this interface.
*/
public
interface
PinnedHeaderAdapter {
/**
* Pinned header state: don't show the header.
*/
public
static
final
int
PINNED_HEADER_GONE = 0;
/**
* Pinned header state: show the header at the top of the list.
*/
public
static
final
int
PINNED_HEADER_VISIBLE = 1;
/**
* Pinned header state: show the header. If the header extends beyond
* the bottom of the first shown element, push it up and clip.
*/
public
static
final
int
PINNED_HEADER_PUSHED_UP = 2;
/**
* Computes the desired state of the pinned header for the given
* position of the first visible list item. Allowed return values are
* {
@link
#PINNED_HEADER_GONE}, {
@link
#PINNED_HEADER_VISIBLE} or
* {
@link
#PINNED_HEADER_PUSHED_UP}.
*/
int
getPinnedHeaderState(
int
position);
/**
* Configures the pinned header view to match the first visible list item.
*
*
@param
header pinned header view.
*
@param
position position of the first visible list item.
*
@param
alpha fading of the header view, between 0 and 255.
*/
void
configurePinnedHeader(View header,
int
position,
int
alpha);
}
private
static
final
int
MAX_ALPHA = 255;
private
PinnedHeaderAdapter mAdapter;
private
View mHeaderView;
private
boolean
mHeaderViewVisible;
private
int
mHeaderViewWidth;
private
int
mHeaderViewHeight;
public
PinnedHeaderListView(Context context) {
super
(context);
}
public
PinnedHeaderListView(Context context, AttributeSet attrs) {
super
(context, attrs);
}
public
PinnedHeaderListView(Context context, AttributeSet attrs,
int
defStyle) {
super
(context, attrs, defStyle);
}
public
void
setPinnedHeaderView(View view) {
mHeaderView = view;
//
Disable vertical fading when the pinned header is present
//
TODO change ListView to allow separate measures for top and bottom fading edge;
//
in this particular case we would like to disable the top, but not the bottom edge.
if
(mHeaderView !=
null
) {
setFadingEdgeLength(0);
}
requestLayout();
}
@Override
public
void
setAdapter(ListAdapter adapter) {
super
.setAdapter(adapter);
mAdapter = (PinnedHeaderAdapter)adapter;
}
@Override
protected
void
onMeasure(
int
widthMeasureSpec,
int
heightMeasureSpec) {
super
.onMeasure(widthMeasureSpec, heightMeasureSpec);
if
(mHeaderView !=
null
) {
measureChild(mHeaderView, widthMeasureSpec, heightMeasureSpec);
mHeaderViewWidth = mHeaderView.getMeasuredWidth();
mHeaderViewHeight = mHeaderView.getMeasuredHeight();
}
}
@Override
protected
void
onLayout(
boolean
changed,
int
left,
int
top,
int
right,
int
bottom) {
super
.onLayout(changed, left, top, right, bottom);
if
(mHeaderView !=
null
) {
mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
configureHeaderView(getFirstVisiblePosition());
}
}
public
void
configureHeaderView(
int
position) {
if
(mHeaderView ==
null
) {
return
;
}
int
state = mAdapter.getPinnedHeaderState(position);
switch
(state) {
case
PinnedHeaderAdapter.PINNED_HEADER_GONE: {
mHeaderViewVisible =
false
;
break
;
}
case
PinnedHeaderAdapter.PINNED_HEADER_VISIBLE: {
mAdapter.configurePinnedHeader(mHeaderView, position, MAX_ALPHA);
if
(mHeaderView.getTop() != 0) {
mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
}
mHeaderViewVisible =
true
;
break
;
}
case
PinnedHeaderAdapter.PINNED_HEADER_PUSHED_UP: {
View firstView = getChildAt(0);
int
bottom = firstView.getBottom();
//
int itemHeight = firstView.getHeight();
int
headerHeight = mHeaderView.getHeight();
int
y;
int
alpha;
if
(bottom < headerHeight) {
y = (bottom - headerHeight);
alpha = MAX_ALPHA * (headerHeight + y) / headerHeight;
}
else
{
y = 0;
alpha = MAX_ALPHA;
}
mAdapter.configurePinnedHeader(mHeaderView, position, alpha);
if
(mHeaderView.getTop() != y) {
mHeaderView.layout(0, y, mHeaderViewWidth, mHeaderViewHeight + y);
}
mHeaderViewVisible =
true
;
break
;
}
}
}
@Override
protected
void
dispatchDraw(Canvas canvas) {
super
.dispatchDraw(canvas);
if
(mHeaderViewVisible) {
drawChild(canvas, mHeaderView, getDrawingTime());
}
}
}
MySectionIndexer.java类，主要是用来提供分组的数据的，主要包括，String[]mSections-->所有的组名，int[] mPositions-->每一个组名在listivew中的位置，当然，他们的长度应该是相同的。
package
com.demo.sectionlistview;
import
java.util.Arrays;
import
android.widget.SectionIndexer;
public
class
MySectionIndexer
implements
SectionIndexer{
private
final
String[] mSections;
//
private
final
int
[] mPositions;
private
final
int
mCount;
/**
*
@param
sections
*
@param
counts
*/
public
MySectionIndexer(String[] sections,
int
[] counts) {
if
(sections ==
null
|| counts ==
null
) {
throw
new
NullPointerException();
}
if
(sections.length !=
counts.length) {
throw
new
IllegalArgumentException(
"The sections and counts arrays must have the same length"
);
}
this
.mSections =
sections;
mPositions
=
new
int
[counts.length];
int
position = 0
;
for
(
int
i = 0; i < counts.length; i++
) {
if
(mSections[i] ==
null
) {
mSections[i]
= ""
;
}
else
{
mSections[i]
=
mSections[i].trim();
}
mPositions[i]
=
position;
position
+=
counts[i];
}
mCount
=
position;
}
@Override
public
Object[] getSections() {
//
TODO Auto-generated method stub
return
mSections;
}
@Override
public
int
getPositionForSection(
int
section) {
//
change by lcq 2012-10-12 section > mSections.length以为>=
if
(section < 0 || section >=
mSections.length) {
return
-1
;
}
System.out.println(
"lcq:section:"+
section);
return
mPositions[section];
}
@Override
public
int
getSectionForPosition(
int
position) {
if
(position < 0 || position >=
mCount) {
return
-1
;
}
//
注意这个方法的返回值，它就是index<0时，返回-index-2的原因
//
解释Arrays.binarySearch，如果搜索结果在数组中，刚返回它在数组中的索引，如果不在，刚返回第一个比它大的索引的负数-1
//
如果没弄明白，请自己想查看api
int
index =
Arrays.binarySearch(mPositions, position);
return
index >= 0 ? index : -index - 2;
//
当index小于0时，返回-index-2，
}
}
当然，adapter也灰常重要，这里简单分析下，因为具体使用时，会根据情况使用不同的adapter，比如说，有数据库的，可以使用SimpleCursorAdapter，也可以使用SimpleAdapter等等，这里使用的原始的listAdapter，比较麻烦，这里要实现上面提到的PinnedHeaderAdapter，还要实现SectionIndexer,主要是用来根据实际位置查找分组的索引，以及根据索引返回组名在实际listview中的位置（这里有点不太好讲，不太懂的，仔细看源码和api）
其他的就是一些adapter的基本应用以及一些android 的基本知识，这里不在讲述，不懂的请提问。
源码下载地址：http://files.cnblogs.com/xiaoQLu/DemoSectionListView_Plus.rar
