Android listView 头部添加透明titleBar

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.npi.blureffect.ListViewActivity" >

<ListView
android:id="@+id/listView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true" >

</ListView>

<com.npi.blureffect.ScrollableImageView
android:id="@+id/blurred_image_header"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#e8e8e8" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="false"
android:layout_alignParentRight="false"
android:layout_alignParentTop="false"
android:layout_centerVertical="true"
android:src="@drawable/demo02" />

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_marginRight="20dp"
android:text="Button" />

</RelativeLayout>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.npi.blureffect.ListViewActivity" >

<com.npi.blureffect.ScrollableImageView
android:id="@+id/blurred_image_header"
android:layout_width="match_parent"
android:layout_height="50dp"
android:background="#e8e8e8" />

</RelativeLayout>

package com.npi.blureffect;

import java.util.ArrayList;
import java.util.List;
import java.util.zip.Inflater;

import com.situ.android.adapter.CommonAdapter;
import com.situ.android.adapter.ViewHolder;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.MeasureSpec;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ImageView;
import android.widget.ListView;

public class ListViewActivity extends Activity {
ScrollableImageView header;
ListView listView;
Bitmap screen;
View listHeader;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_view);
listView = (ListView) findViewById(R.id.listView1);
header = (ScrollableImageView) findViewById(R.id.blurred_image_header);

List<Integer> contents = new ArrayList<Integer>();
contents.add(R.drawable.demo01);
contents.add(R.drawable.demo02);
contents.add(R.drawable.demo03);
contents.add(R.drawable.demo04);
contents.add(R.drawable.demo05);
contents.add(R.drawable.demo06);
contents.add(R.drawable.demo07);
contents.add(R.drawable.demo08);
contents.add(R.drawable.demo09);
contents.add(R.drawable.demo10);
contents.add(R.drawable.demo11);
contents.add(R.drawable.demo12);
contents.add(R.drawable.demo13);
contents.add(R.drawable.demo14);
contents.add(R.drawable.demo15);
listView.setAdapter(new CommonAdapter(ListViewActivity.this,R.layout.list_activity_item,contents) {

@Override
public void convert(ViewHolder holder, int position, Object object) {
// TODO Auto-generated method stub
ImageView img = (ImageView)holder.getView(R.id.imageView1);
img.setImageResource((Integer)object);
}
});

initListView(listView, header);
}

int totalHeight=0;
int initHeight = 0;
private void initListView(final ListView listView,final ScrollableImageView header){
LayoutInflater inflater = getLayoutInflater();
listHeader = inflater.inflate(R.layout.list_header, null);
listView.addHeaderView(listHeader);
listView.setOnScrollListener(new OnScrollListener() {
int X = 0;
int Y = 0;
int height = 0;
/**
* 获取当前滑动的精准位置，仅能用于行高均相同的listview
* @param mListView
* @return
*/
public int getScrollY(final AbsListView mListView) {
mListView.post(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
View c = mListView.getChildAt(0);
if (c == null) {
return ;
}
int firstVisiblePosition = mListView.getFirstVisiblePosition();
int top = c.getTop();
//						    Log.i("Alex", "子元素的top是"+top+"头的高度是"+listHeader.getHeight()+"  :"+listHeader.getMeasuredHeight());
//重中之重的方法！！！！！！！！！！！！！！！！！！！！！！！
Log.i("Alex", "计算结果是 "+top+"+"+(firstVisiblePosition-1)+" *"+c.getHeight()+" +"+listHeader.getHeight()+"  :"+listHeader.getMeasuredHeight());
if(c.getHeight()==listHeader.getHeight()){
height =  -top + (firstVisiblePosition) * c.getHeight() ;
}else{
height =  -top + (firstVisiblePosition-1) * c.getHeight()+listHeader.getHeight() ;
}
}
});
return height;
}

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// TODO Auto-generated method stub
Log.i("Alex", "listView滚动状态改变了:::"+scrollState);
switch(scrollState){
case OnScrollListener.SCROLL_STATE_IDLE://空闲状态
Log.i("Alex", "现在是空闲状态");
break;
case OnScrollListener.SCROLL_STATE_FLING://滚动状态
Log.i("Alex", "现在是滚动状态");
break;
case OnScrollListener.SCROLL_STATE_TOUCH_SCROLL://触摸后滚动
Log.i("Alex", "现在是惯性状态");
break;
}

}

@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// TODO Auto-generated method stub
//				Log.i("Alex", "正在滚动。。第一个可见item是"+firstVisibleItem+" 可见item的数量是"+visibleItemCount+" /"+totalItemCount);
//				X = listView.getScrollX();
Y = getScrollY(view);
if(Y<initHeight){
Log.i("Alex", "现在是刚进来");
}
if(Y>initHeight && Y >totalHeight-listHeader.getHeight()){
Log.i("Alex", "正在重新截图。。。................................................................................。。。。。。。。。。。。");

view.post(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
Bitmap subScreen = Blur.fastblur(ListViewActivity.this, getbBitmap(listView), 15);
screen = concactBitmapVertical(screen, subScreen);
subScreen.recycle();//消除内存
totalHeight = screen.getHeight();
header.setoriginalImage(screen);
}
});

}
Log.i("Alex", "现在要显示到："+Y);
header.handleScroll(Y, 0);
}
});

listView.post(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
screen = getbBitmap(listView);
initHeight = screen.getHeight();
screen = Blur.fastblur(ListViewActivity.this, screen, 15);
totalHeight = screen.getHeight();
header.setoriginalImage(screen);
}
});
}

/**
* 截图listview，这个截图方法有bug,在快速滑动和慢速滑动的时候截图结果不同
* **/
public static Bitmap getbBitmap(ListView listView) {
int h = 0;
Bitmap bitmap = null;
// 获取listView实际高度
Log.i("Alex", "子元素数量是"+listView.getChildCount());
for (int i = 0; i < listView.getChildCount(); i++) {
h += listView.getChildAt(i).getHeight();
}
Log.d("Alex", "实际高度:" + h);
Log.d("Alex", "list 高度:" + listView.getHeight());
// 创建对应大小的bitmap
bitmap = Bitmap.createBitmap(listView.getWidth(), h,
Bitmap.Config.ARGB_8888);
final Canvas canvas = new Canvas(bitmap);
listView.draw(canvas);
return bitmap;
}

/**
* 这个方法不能用于listView中的contentView，不然被测量之前的contentVIew就都没了
* @param view
* @return
*/
public static Bitmap convertViewToBitmap(View view) {
view.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
view.buildDrawingCache();
Bitmap bitmap = view.getDrawingCache();
if (bitmap != null) {
System.out.println("这不是nullde1");
Log.d("nullde1", "nullde1");
} else {
System.out.println("这nullnulllnulnlul");
}
return bitmap;
}

/**
* 将两张位图拼接成一张(横向拼接)
*
* @param first
* @param second
* @return
*/
private Bitmap concactBitmapHorizantal(Bitmap first, Bitmap second) {
int width =first.getWidth() + second.getWidth();
int height = Math.max(first.getHeight(), second.getHeight());
Bitmap result = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas canvas = new Canvas(result);
canvas.drawBitmap(first, 0, 0, null);
canvas.drawBitmap(second, first.getWidth(), 0, null);
return result;
}
/**
* 将两张位图拼接成一张(横向拼接)
*
* @param first
* @param second
* @return
*/
private Bitmap concactBitmapVertical(Bitmap first, Bitmap second) {
int width =Math.max(first.getWidth(), second.getWidth());
int height = first.getHeight()+second.getHeight();
Bitmap result = Bitmap.createBitmap(width, height, Config.ARGB_4444);
Canvas canvas = new Canvas(result);
canvas.drawBitmap(first, 0, 0, null);//先画第一个
canvas.drawBitmap(second, 0, first.getHeight(), null);//在第一个的下面画第二个
return result;
}

}