Android 网络下载图片

2中方法：

1.

public byte[] downloadResource(Context context, String url)
throws ClientProtocolException, IOException {
isStop = false;
ByteArrayBuffer buffer = null;
HttpGet hp = new HttpGet(url);
httpClient = new DefaultHttpClient();
String netType = isNetType(context);
if (netType != null & netType.equals("cmwap")) {
HttpHost proxy = new HttpHost("10.0.0.172", 80);
httpClient.getParams().setParameter(ConnRouteParams.DEFAULT_PROXY,
proxy);
}
HttpConnectionParams.setConnectionTimeout(httpClient.getParams(),
5 * 1000);
HttpConnectionParams.setSoTimeout(httpClient.getParams(), 60 * 1000);HttpResponse response = httpClient.execute(hp);
if (response.getStatusLine().getStatusCode() == 200) {
inputstream = response.getEntity().getContent();
if (inputstream != null) {
int i = (int) response.getEntity().getContentLength();
buffer = new ByteArrayBuffer(1024);
byte[] tmp = new byte[1024];
int len;
while (((len = inputstream.read(tmp)) != -1)
&& (false == isStop)) {
buffer.append(tmp, 0, len);
}
}
cancel();
}
return buffer.toByteArray();
}

调用方法：

protected Bitmap doInBackground(WonderfulprogramInfo... params)
{
Bitmap bitmap = null;
try
{
String urls = Constant.url + params[0].getWonderfulImgUrl();
boolean isExists = Files.compare(urls);
if (isExists == false)
{//网络下载图片数据
Net net = new Net();
byte[] data = net.downloadResource(HomeActivity.this, urls);
bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
imagesCache.put(urls, bitmap); // 把下载好的图片保存到缓存中
Files.saveImage(urls, data);
} else
{//本地读取图片数据
byte[] data = Files.readImage(urls);
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inPreferredConfig = Bitmap.Config.RGB_565;
opt.inPurgeable = true;
opt.inInputShareable = true;
// //获取资源图片
// InputStream is =
// context.getResources().openRawResource(resId);
// return BitmapFactory.decodeStream(is,null,opt);bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, opt);
imagesCache.put(urls, bitmap); // 把下载好的图片保存到缓存中
}

方法二：

class DownLoadTask extends AsyncTask<String, Void, Bitmap> {
private ImageView imageView;
private Integer positions;public DownLoadTask(ImageView view, int position) {
imageView = view;
this.positions = position;
}protected Bitmap doInBackground(String... params) {
URL url;
try {
url = new URL(params[0]);
InputStream is = url.openStream();
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inPreferredConfig = Bitmap.Config.RGB_565;
opt.inPurgeable = true;
opt.inInputShareable = true;
// 获取资源图片
Bitmap bitmap = BitmapFactory.decodeStream(is, null, opt);
HomeActivity.TopGalleryBitmap.put(positions, bitmap);
return bitmap;
} catch (OutOfMemoryError err) {
err.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}return null;
}protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
imageView.setImageBitmap(result);
}
}