android从网络中获取一张图片

1.先看看简单的布局main.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="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/urlpath" />
    <EditText
        android:id="@+id/edit"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="http://img1.gtimg.com/4/402/40281/4028144_550x550_0.jpg" />
    <Button
         android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button" />
    <ImageView 
        android:id="@+id/imageview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
         />
</LinearLayout>

2.接着看看打开网络服务的类imageViewService.java

package com.wang.service;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import com.wang.utils.Streamutil;

public class imageViewService {
	public static byte[] getImage(String path) throws Exception {
		URL url=new URL("http://img1.gtimg.com/4/402/40281/4028144_550x550_0.jpg");
		HttpURLConnection conn=(HttpURLConnection)url.openConnection();//打开网络连接
		conn.setRequestMethod("GET");//所用的方式为get 、post
		conn.setConnectTimeout(5*1000);
		
		InputStream inputstream=conn.getInputStream();// 通过输入流获取图片数据
	     return Streamutil.readInputStream(inputstream);//得到图片的二进制数据
		
	}
	
	

}

3.接着编写从输入流中获取数据Streamutil.java

package com.wang.utils;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;

public class Streamutil {
	//从输入流中获取数据
	public static byte[] readInputStream(InputStream inputstream) throws Exception{
		
		ByteArrayOutputStream outstream=new ByteArrayOutputStream();//缓冲区的数据存储
		byte[] buffer=new byte[1024];//缓冲区
		int len=0;
		while((len=inputstream.read(buffer))!=-1)// 如果不等与-1则不断的进行读取
		{
			
			outstream.write(buffer,0,len);
			
		}
		inputstream.close();
		return outstream.toByteArray();
	}
}

4.然后看一下活动类ImageViewnetActivity.java

package com.wang;

import com.wang.service.imageViewService;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;

public class ImageViewnetActivity extends Activity {
  
	private EditText pathtext;
	private ImageView imageview;
	private static final String TAG="ImageViewnetActivity";
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        pathtext=(EditText)findViewById(R.id.edit);
        imageview=(ImageView)findViewById(R.id.imageview);
        Button button=(Button)findViewById(R.id.button);
        button.setOnClickListener(new  OnClickListener() {
			
			public void onClick(View v) {
				String path= pathtext.getText().toString();
				try {
					byte[] data =imageViewService.getImage(path);
					Bitmap bitmap=BitmapFactory.decodeByteArray(data, 0, data.length);//生成位图
					imageview.setImageBitmap(bitmap);//显示图片
				} catch (Exception e) {
					// TODO Auto-generated catch block
					
					Toast.makeText(ImageViewnetActivity.this, R.string.error, 1).show();
				    Log.e(TAG,e.toString());				}
				
			}
		});
        
    }
}