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();
        }
    };
}