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<!-- 访问网络的权限 -->
<uses-permission android:name="android.permission.INTERNET" />
<!-- 文件读取的权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<!-- 向SD卡中创建或者删除的权限。 -->
<uses-permission android:name="andorid.permission.MONUN_UNMOUNT_FILESYSTEMS"/>

package com.xjw.test;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener{

	Button content;
	ImageView image;
	Bitmap bitmap;
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		content=(Button)findViewById(R.id.content);
		image=(ImageView)findViewById(R.id.image);
		
		content.setOnClickListener(this);;
		image.setOnClickListener(this);;
	}
	
	/**
	 * 获取网络图片
	 * @param imageurl 图片网络地址
	 * @return Bitmap 返回位图
	 */
	public Bitmap GetImageInputStream(String imageurl){
		URL url;
		HttpURLConnection connection=null;
		Bitmap bitmap=null;
		try {
			url = new URL(imageurl);
			connection=(HttpURLConnection)url.openConnection();
			connection.setConnectTimeout(6000); //超时设置
			connection.setDoInput(true); 
			connection.setUseCaches(false); //设置不使用缓存
			InputStream inputStream=connection.getInputStream();
			bitmap=BitmapFactory.decodeStream(inputStream);
			inputStream.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return bitmap;
	}
	
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.content:
			//加入网络图片地址
			new Task().execute("http://pic.4j4j.cn/upload/pic/20130617/55695c3c95.jpg");
			break;
			
		case R.id.image:
			//点击图片后将图片保存到SD卡跟目录下的Test文件夹内
			SavaImage(bitmap, Environment.getExternalStorageDirectory().getPath()+"/Test");
			Toast.makeText(getBaseContext(), "图片保存", Toast.LENGTH_SHORT).show();
			break;
			
		default:
			break;
		}
	}
	
	Handler handler=new Handler(){
		public void handleMessage(android.os.Message msg) {
			if(msg.what==0x123){
				image.setImageBitmap(bitmap);
			}
		};
	};
	
	
	/**
	 * 异步线程下载图片
	 *
	 */
	class Task extends AsyncTask<String, Integer, Void>{

		protected Void doInBackground(String... params) {
			bitmap=GetImageInputStream((String)params[0]);
			return null;
		}
		
		protected void onPostExecute(Void result) {
			super.onPostExecute(result);
			Message message=new Message();
			message.what=0x123;
			handler.sendMessage(message);
		}
		
	}
	
	/**
	 * 保存位图到本地
	 * @param bitmap
	 * @param path 本地路径
	 * @return void
	 */
	public void SavaImage(Bitmap bitmap, String path){
		File file=new File(path);
		FileOutputStream fileOutputStream=null;
		//文件夹不存在，则创建它
		if(!file.exists()){
			file.mkdir();
		}
		try {
			fileOutputStream=new FileOutputStream(path+"/"+System.currentTimeMillis()+".png");
			bitmap.compress(Bitmap.CompressFormat.JPEG, 100,fileOutputStream);
			fileOutputStream.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}