保存图片到本地目录和获取

因为是对互联网和内存操作，所以我们要添加如下权限:

//代码如下所示:

package com.itfom.getpicfromnet;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
@SuppressLint("HandlerLeak")
public class MainActivity extends Activity {
private ImageView iv_pic;
private Button btn_get;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_get = (Button) findViewById(R.id.btn_get);
iv_pic = (ImageView) findViewById(R.id.iv_img);
//设置监听事件
btn_get.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//开启子线程
new Thread(){
public void run() {
try {
String urlPath = "http://pic7.nipic.com/20100607/4791134_172835008083_2.jpg";
URL url = new URL(urlPath);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(6*1000);  // 注意要设置超时，设置时间不要超过10秒，避免被android系统回收
if (conn.getResponseCode() != 200) throw new RuntimeException("请求url失败");
InputStream inSream = conn.getInputStream();
//把图片保存到项目的根目录
readAsFile(inSream, new File(Environment.getExternalStorageDirectory()+"/"+"test.jpg"));
Message msg=new Message();
msg.what=0;
handler.sendMessage(msg);
} catch (Exception e) {
e.printStackTrace();
}
};
}.start();
}
});
}
public static void readAsFile(InputStream inSream, File file) throws Exception{
FileOutputStream outStream = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = -1;
while( (len = inSream.read(buffer)) != -1 ){
outStream.write(buffer, 0, len);
}
outStream.close();
inSream.close();
}
//创建Handler
Handler handler=new Handler(){
public void handleMessage(android.os.Message msg) {
if(msg.what==0){
//开始绑定数据
iv_pic.setImageBitmap(BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/test.jpg"));  // 获取保存到根目录的图片并展示
}
};
};
}

/**
* 保存到本地文件
* @param inSream
* @param file
* @throws Exception
* readAsFile(inSream, new File(Environment.getExternalStorageDirectory()+"/"+"test.jpg"));
* iv_pic.setImageBitmap(BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/test.jpg")); 获取
*/
public static void readAsFile(InputStream inSream, File file) throws Exception{
FileOutputStream outStream = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = -1;
while( (len = inSream.read(buffer)) != -1 ){
outStream.write(buffer, 0, len);
}
outStream.close();
inSream.close();
}

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>