android 下载图片到本地 sdcard

示意图：



首先获取网络数据，先加权限，以防忘记：

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

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

测试前先保持手机网络连接状态为连接状态。

以下是代码实现：

注意线程的使用机制，开辟新线程的时机要控制好

package com.jiaruihuademo.getpicfrominternet;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.MalformedURLException;

import java.net.URI;

import java.net.URL;

import android.os.Bundle;

import android.os.Environment;

import android.os.Handler;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ImageView;

public class MainActivity extends Activity implements OnClickListener {

private Button getbtn;
private ImageView image;
private Bitmap bitmap;
private String picURL = "http://c.hiphotos.bdimg.com/album/s%3D900%3Bq%3D90/" +
"sign=e6a9774cd31b0ef468e8945eedff20e7/8644ebf81a4c510f9b92dd78615925" +
"2dd42aa579.jpg";
private final static String ALBUM_PATH = Environment
.getExternalStorageDirectory() + "/mypic_data/";
private int GETPIC_OK = 0x123;
private String PICNAEM = "mypic.png";

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}

private void init() {
getbtn = (Button) findViewById(R.id.get);
image = (ImageView) findViewById(R.id.image);
getbtn.setOnClickListener(this);

}

Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {

if (msg.what == 0x123) {
image.setImageBitmap(bitmap);
}

};
};

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
new Thread(new Runnable() {

@Override
public void run() {
// TODO Auto-generated method stub
URL url;
try {
url = new URL(picURL);
InputStream is = url.openStream();
bitmap = BitmapFactory.decodeStream(is);
saveFile(bitmap, "yangmi.jpg");
handler.sendEmptyMessage(GETPIC_OK);
is.close();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}).start();
}

// 指定保存的路径：
public void saveFile(Bitmap bm, String fileName) throws IOException {
File dirFile = new File(ALBUM_PATH);
if (!dirFile.exists()) {
dirFile.mkdir();
}
File myCaptureFile = new File(ALBUM_PATH + fileName);
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream(myCaptureFile));
bm.compress(Bitmap.CompressFormat.JPEG, 80, bos);
bos.flush();
bos.close();
}

}

源码下载

以上的代码不够完善，我会后续更新，欢迎交流，评论。