我试图用图片和文字显示的ListView，我已经使用Simpleadapter类，但我无法显示的ListView可以在任何一个可以帮助我，我做错了什么？
在这里我的代码：
public class HostsActivity extends ListActivity {
public final static String ITEM_TITLE = "title";
public final static String ITEM_IMAGE = "Image";
private List<HostsProfile> hostsProfile1;
List<Map<String, ?>> security = new LinkedList<Map<String, ?>>();
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.hostslist);
Bundle recdData = getIntent().getExtras();
hostsProfile1 = recdData.getParcelableArrayList("hostsProfile");
List<Map<String, ?>> security1 = new LinkedList<Map<String, ?>>();
for (HostsProfile msg1 : hostsProfile1) {
// Log.v("image","Image path"+msg.getImage());
try {
URL url = new URL(msg1.getMediathumbnail());
HttpURLConnection con = (HttpURLConnection) url.openConnection();
InputStream is = con.getInputStream();
Bitmap img = BitmapFactory.decodeStream(is);
security.add(createItem(msg1.getTitle(), img));
} catch (Throwable t) {
}
}
/*for(int i=0; i<security.size(); i++){
security.remove(0);
}
*/
SimpleAdapter adapter1 = new SimpleAdapter(this, security1,
R.layout.image_text_layout1, new String[] { ITEM_IMAGE,
ITEM_TITLE }, new int[] { R.id.feed_image,
R.id.job_text });
adapter1.setViewBinder(new MyViewBinder());
this.setListAdapter(adapter1);
}
public Map<String, ?> createItem(String title, Bitmap Image) {
Map<String, Object> item = new HashMap<String, Object>();
item.put(ITEM_TITLE, title);
item.put(ITEM_IMAGE, Image);
return item;
}
//for ImageView
class MyViewBinder implements ViewBinder {
public boolean setViewValue(View view, Object data,
String textRepresentation) {
if ((view instanceof ImageView) & (data instanceof Bitmap)) {
ImageView image1 = (ImageView) view;
Bitmap bm = (Bitmap) data;
image1.setImageBitmap(bm);
return true;
}
return false;
}
}
}
下面是我的布局XML文件：
image_text_layout1：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="wrap_content">
<ImageView android:id="@+id/feed_image"
android:layout_width="60dp"
android:layout_height="60dp"
android:gravity="center_vertical"
android:paddingRight="3dp"
android:paddingLeft="2dp"/>
<TextView android:id="@+id/job_text"
android:layout_width="wrap_content"
android:layout_height="60dp"
android:textColor="#000000"
android:textStyle="bold"
android:gravity="center_vertical"/>
<!--android:paddingTop="5dip"
android:paddingBottom="28dip"
android:paddingLeft="8dip"
android:paddingRight="8dip" />-->
</LinearLayout>
hostslist.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/background"
>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="@+id/linearlayout01"
android:layout_width="300dp"
android:layout_height="45dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="52dp"
android:orientation="vertical" >
</LinearLayout>
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="230dp"
android:layout_alignParentRight="true"
android:layout_marginTop="107dp"
android:cacheColorHint="#00000000">
</ListView>
</RelativeLayout>
</LinearLayout>
做一个CustomListview项目：
custom ListView.Java
package com.example.customlistview;
import java.util.ArrayList;
import android.os.Bundle;
import android.widget.ListView;
import android.app.Activity;
public class CustomListView extends Activity {
ArrayList<Contact> imageArry = new ArrayList<Contact>();
ContactImageAdapter adapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// add image and text in arraylist
imageArry.add(new Contact(R.drawable.facebook, "FaceBook"));
imageArry.add(new Contact(R.drawable.google, "Google"));
imageArry.add(new Contact(R.drawable.ical, "Ical"));
imageArry.add(new Contact(R.drawable.outlook, "Outlook"));
imageArry.add(new Contact(R.drawable.twitter, "Twitter"));
// add data in contact image adapter
adapter = new ContactImageAdapter(this, R.layout.list, imageArry);
ListView dataList = (ListView) findViewById(R.id.list);
dataList.setAdapter(adapter);
}
}
contact.Java
package com.example.customlistview;
public class Contact
{
int image;
String name;
public int getImage() {
return image;
}
public void setImage(int image) {
this.image = image;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Contact(int image, String name) {
super();
this.image = image;
this.name = name;
}
}
contact image adapter.Java
package com.example.customlistview;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class ContactImageAdapter extends ArrayAdapter<Contact> {
Context context;
int layoutResourceId;
ArrayList<Contact> data=new ArrayList<Contact>();
public ContactImageAdapter(Context context, int layoutResourceId, ArrayList<Contact> data) {
super(context, layoutResourceId, data);
this.layoutResourceId = layoutResourceId;
this.context = context;
this.data = data;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
ImageHolder holder = null;
if(row == null)
{
LayoutInflater inflater = ((Activity)context).getLayoutInflater();
row = inflater.inflate(layoutResourceId, parent, false);
holder = new ImageHolder();
holder.txtTitle = (TextView)row.findViewById(R.id.txtTitle);
holder.imgIcon = (ImageView)row.findViewById(R.id.imgIcon);
row.setTag(holder);
}
else
{
holder = (ImageHolder)row.getTag();
}
Contact myImage = data.get(position);
holder.txtTitle.setText(myImage.name);
int outImage=myImage.image;
holder.imgIcon.setImageResource(outImage);
return row;
}
static class ImageHolder
{
ImageView imgIcon;
TextView txtTitle;
}
}
main.xml中
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ListView
android:id="@+id/list"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="0.55" >
</ListView>
</LinearLayout>
list.xml
<?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="horizontal"
android:padding="10dp" ><ImageView
android:id="@+id/imgIcon"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.71"
android:gravity="center_vertical"/>
<TextView
android:id="@+id/txtTitle"
android:layout_width="80dp"
android:layout_height="fill_parent"
android:gravity="center_vertical"
android:textSize="14dp"
android:layout_marginLeft="7dp" />
</LinearLayout>
放图标绘制，这是主要的活动图像阵列中使用。
我建议你使用自定义列表视图中使用自定义适配器。
一个例子是可以在下面的链接。
android-custom-listview-with-image-and-text
使用平滑滚动和性能viewholder。
您还可以使用懒列表或通用图像加载器。
两者都使用缓存。
Lazy List and Universal Image Loader
检查viewholder和装载位图有效以下链接
Listview smooth scrolling using ViewHolder
The world of Listview talk by android developers at google的演讲是关于viewholder和列表视图性能。
添加类延迟加载FileCache.java
========
public class FileCache {
private File cacheDir;
public FileCache(Context context){
//Find the dir to save cached images
if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
cacheDir=new File(android.os.Environment.getExternalStorageDirectory(),"LazyList");
else
cacheDir=context.getCacheDir();
if(!cacheDir.exists())
cacheDir.mkdirs();
}
public File getFile(String url){
//I identify images by hashcode. Not a perfect solution, good for the demo.
String filename=String.valueOf(url.hashCode());
//Another possible solution (thanks to grantland)
//String filename = URLEncoder.encode(url);
File f = new File(cacheDir, filename);
return f;
}
public void clear(){
File[] files=cacheDir.listFiles();
if(files==null)
return;
for(File f:files)
f.delete();
}
}
========= ImageLoader.java
public class ImageLoader {
MemoryCache memoryCache=new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
Handler handler=new Handler();//handler to display images in UI thread
public ImageLoader(Context context){
fileCache=new FileCache(context);
executorService=Executors.newFixedThreadPool(5);
}
final int stub_id=R.drawable.stub;
public void DisplayImage(String url, ImageView imageView)
{
imageViews.put(imageView, url);
Bitmap bitmap=memoryCache.get(url);
if(bitmap!=null)
imageView.setImageBitmap(bitmap);
else
{
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView)
{
PhotoToLoad p=new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url)
{
File f=fileCache.getFile(url);
//from SD cache
Bitmap b = decodeFile(f);
if(b!=null)
return b;
//from web
try {
Bitmap bitmap=null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is=conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
conn.disconnect();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex){
ex.printStackTrace();
if(ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f){
try {
//decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream stream1=new FileInputStream(f);
BitmapFactory.decodeStream(stream1,null,o);
stream1.close();
//Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE=70;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
//decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize=scale;
FileInputStream stream2=new FileInputStream(f);
Bitmap bitmap=BitmapFactory.decodeStream(stream2, null, o2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e) {
}
catch (IOException e) {
e.printStackTrace();
}
return null;
}
//Task for the queue
private class PhotoToLoad
{
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i){
url=u;
imageView=i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad){
this.photoToLoad=photoToLoad;
}
public void run() {
try{
if(imageViewReused(photoToLoad))
return;
Bitmap bmp=getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if(imageViewReused(photoToLoad))
return;
BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
handler.post(bd);
}catch(Throwable th){
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad){
String tag=imageViews.get(photoToLoad.imageView);
if(tag==null || !tag.equals(photoToLoad.url))
return true;
return false;
}
//Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable
{
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
public void run()
{
if(imageViewReused(photoToLoad))
return;
if(bitmap!=null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
====== MemoryCache.java
public class MemoryCache {
private static final String TAG = "MemoryCache";
private Map<String, Bitmap> cache=Collections.synchronizedMap(
new LinkedHashMap<String, Bitmap>(10,1.5f,true));//Last argument true for LRU ordering
private long size=0;//current allocated size
private long limit=1000000;//max memory in bytes
public MemoryCache(){
//use 25% of available heap size
setLimit(Runtime.getRuntime().maxMemory()/4);
}
public void setLimit(long new_limit){
limit=new_limit;
Log.i(TAG, "MemoryCache will use up to "+limit/1024./1024.+"MB");
}
public Bitmap get(String id){
try{
if(!cache.containsKey(id))
return null;
//NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78
return cache.get(id);
}catch(NullPointerException ex){
ex.printStackTrace();
return null;
}
}
public void put(String id, Bitmap bitmap){
try{
if(cache.containsKey(id))
size-=getSizeInBytes(cache.get(id));
cache.put(id, bitmap);
size+=getSizeInBytes(bitmap);
checkSize();
}catch(Throwable th){
th.printStackTrace();
}
}
private void checkSize() {
Log.i(TAG, "cache size="+size+" length="+cache.size());
if(size>limit){
Iterator<Entry<String, Bitmap>> iter=cache.entrySet().iterator();//least recently accessed item will be the first one iterated
while(iter.hasNext()){
Entry<String, Bitmap> entry=iter.next();
size-=getSizeInBytes(entry.getValue());
iter.remove();
if(size<=limit)
break;
}
Log.i(TAG, "Clean cache. New size "+cache.size());
}
}
public void clear() {
try{
//NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78
cache.clear();
size=0;
}catch(NullPointerException ex){
ex.printStackTrace();
}
}
long getSizeInBytes(Bitmap bitmap) {
if(bitmap==null)
return 0;
return bitmap.getRowBytes() * bitmap.getHeight();
}
}
===== Utils.java
public class Utils {
public static void CopyStream(InputStream is, OutputStream os)
{
final int buffer_size=1024;
try
{
byte[] bytes=new byte[buffer_size];
for(;;)
{
int count=is.read(bytes, 0, buffer_size);
if(count==-1)
break;
os.write(bytes, 0, count);
}
}
catch(Exception ex){}
}
}
==== ContactImageAdapte.java
public class ContactImageAdapter extends ArrayAdapter<Contact>{
Context context;
int layoutResourceId;
public ImageLoader imageLoader;
ArrayList<Contact> data=new ArrayList<Contact>();
public ContactImageAdapter(Context context, int layoutResourceId, ArrayList<Contact> data) {
super(context, layoutResourceId, data);
this.layoutResourceId = layoutResourceId;
this.context = context;
this.data = data;
this.imageLoader=new ImageLoader(context);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
ImageHolder holder = null;
if(row == null)
{
LayoutInflater inflater = ((Activity)context).getLayoutInflater();
row = inflater.inflate(layoutResourceId, parent, false);
holder = new ImageHolder();
holder.txtTitle = (TextView)row.findViewById(R.id.txtTitle);
holder.imgIcon = (ImageView)row.findViewById(R.id.imgIcon);
row.setTag(holder);
}
else
{
holder = (ImageHolder)row.getTag();
}
Contact myImage = data.get(position);
holder.txtTitle.setText(myImage.name);
int outImage=myImage.image;
imageLoader.DisplayImage(listres.ItemImage,holder.ItamImage);
return row;
}
static class ImageHolder
{
ImageView imgIcon;
TextView txtTitle;
}
}
=====尝试这