android 下载保存图片

引用：http://www.linuxidc.com/Linux/2011-06/37233.htm

1.java代码，下载图片的主程序

先实现显示图片，然后点击下载图片按钮，执行下载功能。

从网络上取得的图片，生成Bitmap时有两种方法，一种是先转换为byte[]，再生成bitmap；一种是直接用InputStream生成bitmap。

publicclassAndroidTest2_3_3 extends Activity {

privatefinalstatic String TAG = "AndroidTest2_3_3";

privatefinalstatic String ALBUM_PATH

= Environment.getExternalStorageDirectory() + "/download_test/";

private ImageView imageView;

private Button btnSave;

private ProgressDialog myDialog = null;

private Bitmap bitmap;

private String fileName;

private String message;

@Override

protectedvoid onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

imageView = (ImageView)findViewById(R.id.imgSource);

btnSave = (Button)findViewById(R.id.btnSave);

String filePath = "http://hi.csdn.net/attachment/201105/21/134671_13059532779c5u.jpg";

fileName = "test.jpg";

try {

//////////////// 取得的是byte数组, 从byte数组生成bitmap

byte[] data = getImage(filePath);

if(data!=null){

bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);// bitmap

imageView.setImageBitmap(bitmap);// display image

}else{

Toast.makeText(AndroidTest2_3_3.this, "Image error!", 1).show();

}

////////////////////////////////////////////////////////

//******** 取得的是InputStream，直接从InputStream生成bitmap ***********/

bitmap = BitmapFactory.decodeStream(getImageStream(filePath));

if (bitmap != null) {

imageView.setImageBitmap(bitmap);// display image

}

//********************************************************************/

Log.d(TAG, "set image ...");

} catch (Exception e) {

Toast.makeText(AndroidTest2_3_3.this,"Newwork error!", 1).show();

e.printStackTrace();

}

// 下载图片

btnSave.setOnClickListener(new Button.OnClickListener(){

publicvoid onClick(View v) {

myDialog = ProgressDialog.show(AndroidTest2_3_3.this, "保存图片", "图片正在保存中，请稍等...", true);

new Thread(saveFileRunnable).start();

}

});

}

/**

* Get image from newwork

* @param path The path of image

* @return byte[]

* @throws Exception

*/

publicbyte[] getImage(String path) throws Exception{

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setConnectTimeout(5 * 1000);

conn.setRequestMethod("GET");

InputStream inStream = conn.getInputStream();

if(conn.getResponseCode() == HttpURLConnection.HTTP_OK){

return readStream(inStream);

}

returnnull;

}

/**

* Get image from newwork

* @param path The path of image

* @return InputStream

* @throws Exception

*/

public InputStream getImageStream(String path) throws Exception{

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

conn.setConnectTimeout(5 * 1000);

conn.setRequestMethod("GET");

if(conn.getResponseCode() == HttpURLConnection.HTTP_OK){

return conn.getInputStream();

}

returnnull;

}

/**

* Get data from stream

* @param inStream

* @return byte[]

* @throws Exception

*/

publicstaticbyte[] readStream(InputStream inStream) throws Exception{

ByteArrayOutputStream outStream = new ByteArrayOutputStream();

byte[] buffer = newbyte[1024];

int len = 0;

while( (len=inStream.read(buffer)) != -1){

outStream.write(buffer, 0, len);

}

outStream.close();

inStream.close();

return outStream.toByteArray();

}

/**

* 保存文件

* @param bm

* @param fileName

* @throws IOException

*/

publicvoid 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();

}

private Runnable saveFileRunnable = new Runnable(){

@Override

publicvoid run() {

try {

saveFile(bitmap, fileName);

message = "图片保存成功！";

} catch (IOException e) {

message = "图片保存失败！";

e.printStackTrace();

}

messageHandler.sendMessage(messageHandler.obtainMessage());

}

};

private Handler messageHandler = new Handler() {

@Override

publicvoid handleMessage(Message msg) {

myDialog.dismiss();

Log.d(TAG, message);

Toast.makeText(AndroidTest2_3_3.this, message, Toast.LENGTH_SHORT).show();

}

};

}

2.main.xml文件，只有一个button和一个ImageView

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:Android="http://schemas.android.com/apk/res/android"

Android:orientation="vertical"

Android:layout_width="fill_parent"

Android:layout_height="fill_parent"

>

<Button

Android:id="@+id/btnSave"

Android:layout_width="wrap_content"

Android:layout_height="wrap_content"

Android:text="保存图片"

/>

<ImageView

Android:id="@+id/imgSource"

Android:layout_width="wrap_content"

Android:layout_height="wrap_content"

Android:adjustViewBounds="true"

/>

</LinearLayout>

3.在mainfest文件中增加互联网权限和写sd卡的权限

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

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

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

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