今天有时间就学习了下在ListView、GridView列表项中清加ProgressBar,小马用最简单的代码实现可以通用的功能，人人都能看懂，哈哈，直接说下，如果你的适配器getView方法返回的View是一个自定义控件的话，有点不好实现哦，不过可以用两个控件之间Visible 、Invisible来切换实现今天的效果，下面的例子是主类、适配器、异步下载类等的都写在一个类里面了，为的是发的博文里一次性看的话方便，如果大家觉得结构不清楚的话根据自身需求自行抽取下，今天的DEMO只是个简单的思路，其它控件列表项中添加进度框大家也可以用如下的方法实现，老规矩，先看效果，再看代码：
(截图有点失真，但无防)
一：效果图如下
二：效果看完了，看下实现的路是怎样的，吼吼：核心代码如下：
package com.example.listviewitemprogress;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
/**
* @author 小马果
* ListView列表项中添加ProgressBar
*/
public class MainActivity extends Activity {
private ListView mListView = null ;
private static final String imgUrl = "http://www.qq510.net/uploads/allimg/100613/2_100613171230_5.jpg";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}
private void init(){
mListView = (ListView)findViewById(R.id.listview);
mListView.setAdapter(new MyListViewAdapter(this));
}
private class MyListViewAdapter extends BaseAdapter{
private LayoutInflater inflater = null;
public MyListViewAdapter(Context con){
inflater = (LayoutInflater)con.getSystemService(LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return Integer.MAX_VALUE;
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return arg0;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder mHolder = new ViewHolder() ;
if(convertView == null){
convertView = inflater.inflate(R.layout.list_item, null);
mHolder.iv = (ImageView)(convertView.findViewById(R.id.iv));
mHolder.mBtn = (Button)(convertView.findViewById(R.id.button));
mHolder.pb = (ProgressBar)(convertView.findViewById(R.id.progressBar1));
mHolder.tv = (TextView)(convertView.findViewById(R.id.textView1));
convertView.setTag(mHolder);
}else{
mHolder = (ViewHolder)convertView.getTag();
}
new AsyncTask() {
private ViewHolder v;
@Override
protected Bitmap doInBackground(ViewHolder... params) {
v = params[0];
return BitmapFactory.decodeStream(getStreamFromURL(imgUrl));
}
@Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
v.pb.setVisibility(View.GONE);
v.mBtn.setVisibility(View.VISIBLE);
v.iv.setImageBitmap(result);
}
}.execute(mHolder);
return convertView;
}
}
static class ViewHolder{
ImageView iv = null ;
Button mBtn = null ;
ProgressBar pb = null ;
TextView tv = null ;
}
static String length;
public static InputStream getStreamFromURL(String imageURL) {
InputStream in=null;
try {
URL url=new URL(imageURL);
HttpURLConnection connection=(HttpURLConnection) url.openConnection();
// connection.setRequestProperty("Connection", "Keep-Alive");//维持长连接
connection.setConnectTimeout(6* 1000);//设置连接超时
if (connection.getResponseCode() != 200) throw new RuntimeException("请求失败");
length = connection.getHeaderField("Content-Length");
in=connection.getInputStream();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return in;
}
}
三：再来看下两个布局吧(为方便查，小马就放一起了：)
主布局文件：
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
