Pulkit,
I had a similar problem. It seems that BitmapFactory silently fails
(returning null) when BufferedInputStream blocks while fetching from
the connection (I think). If the BufferedInputStream is coming from an
SD source, it works because it doesn't block (I think). The solution
for me was to download the entire stream as a byte array first, and
then call BitmapFactory.decodeByteArray(...)
To do that efficiently, I got the advice to read bytes from a
DataInputStream, filling up fixed sized chunks at a time until the
input stream is finished, and then copying the data from those chunks
into a final byte array (now that we know the full size of the
download). Here's some example code for this:
///////////////////////////////////////////////////////////////
// example of using Bitmapfactory.decodeByteArray instead of
Bitmapfactory.decodeStream
public static Bitmap fetchImage(URL url, String userAgent) throws
IOException {
byte[] bitmapByteArray = JsonUtils.fetchUrlBytes(url,
userAgent );
Bitmap bm = BitmapFactory.decodeByteArray(bitmapByteArray, 0,
bitmapByteArray.length);
return bm;
}
///////////////////////////////////////////////////////////////
// example of downloading a byte array in chunks
private static final int CHUNKSIZE = 8192; //size of fixed
chunks
private static final int BUFFERSIZE = 1024; //size of
reading buffer
public static byte[] fetchUrlBytes(URL url, String userAgent )
throws IOException {
HttpURLConnection connection = null;
connection = ( HttpURLConnection ) url.openConnection();
if(userAgent != null) {
connection.setRequestProperty("User-Agent", userAgent);
}
connection.setConnectTimeout(5000);
connection.setReadTimeout(5000);
int bytesRead = 0;
byte[] buffer = new byte[BUFFERSIZE]; //initialize buffer
byte[] fixedChunk = new byte[CHUNKSIZE]; //initialize 1st
chunk
ArrayList<byte[]> BufferChunkList = new ArrayList<byte[]>(); //
List of chunk data
int spaceLeft = CHUNKSIZE;
int chunkIndex = 0;
DataInputStream in = new DataInputStream
( connection.getInputStream() );
while( ( bytesRead = in.read( buffer ) ) != -1 ) { //loop
until the DataInputStream is completed
if(bytesRead > spaceLeft) {
//copy to end of current chunk
System.arraycopy(buffer, 0, fixedChunk, chunkIndex,
spaceLeft);
BufferChunkList.add(fixedChunk);
//create a new chunk, and fill in the leftover
fixedChunk = new byte[CHUNKSIZE];
chunkIndex = bytesRead - spaceLeft;
System.arraycopy(buffer, spaceLeft, fixedChunk, 0,
chunkIndex);
} else {
//plenty of space, just copy it in
System.arraycopy(buffer, 0, fixedChunk, chunkIndex,
bytesRead);
chunkIndex = chunkIndex + bytesRead;
}
spaceLeft = CHUNKSIZE - chunkIndex;
}
if (in != null) {
in.close();
}
// copy it all into one big array
int responseSize = (BufferChunkList.size() * CHUNKSIZE) +
chunkIndex;
byte[] responseBody = new byte[responseSize];
int index = 0;
for(byte[] b : BufferChunkList) {
System.arraycopy(b, 0, responseBody, index, CHUNKSIZE);
index = index + CHUNKSIZE;
}
System.arraycopy(fixedChunk, 0, responseBody, index,
chunkIndex);
return responseBody;
}
On Jul 28, 10:55 pm, Pulkit <[email protected]> wrote:
> Hi All,
>
> In my app I am downloading images from a remote server and putting it
> into a gallery and displaying it. The problem is that when i do it on
> the emulator it works absolutely fine but when i do it on the phone
> few of the images come and a few arenull. I tried many ways but I am
> not able to find the perfect way. The images on my server are of 50 kb
> max. But still some are downloaded and rest are not. it would be
> really great if someone could help me asap coz i need to make this app
> live by this weekend.
>
> Here is the code snippet to download the images from the server.
>
> public Bitmap getImage(String photoUrl) {
> Bitmap image =null;
> if (!photoUrl.equals("")) {
> if(photoUrl.contains(" ")) {
> photoUrl = photoUrl.replaceAll(" ", "%20");
> }
> try {
> URLConnection conn = new
> URL(photoUrl).openConnection();
> conn.connect();
> InputStream inStream =
> conn.getInputStream();
> BufferedInputStream bis = new
> BufferedInputStream(inStream);
>
> image
> =BitmapFactory.decodeStream(bis);
>
> bis.close();
> inStream.close();
> } catch (MalformedURLException e) {
> e.printStackTrace();
> } catch (IOException e) {
> image
> =BitmapFactory.decodeResource(getResources(),
> R.drawable.image_not_available);
> }
> } else {
> image =BitmapFactory.decodeResource(getResources(),
> R.drawable.image_not_available);
> }
> return image;
> }
>
> Also is there any other way of loading the images in a seperate thread
> like it happens in the android market.
> please reply.
>
> Thanks
> Pulkit
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