Bitmap cannot properly decode the byteArray which represents data from a file - java

I've the following code:
File file = new File(filepath);
byte[] fileData = new byte[(int) file.length()];
DataInputStream dis = null;
try {
dis = new DataInputStream(new FileInputStream(file));
dis.readFully(fileData);
dis.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Bitmap bm = BitmapFactory.decodeByteArray(fileData,0, fileData.length);
I succesfully manage to fill fileData with bytes, although to be honest I think there are too few bytes to represent the content of the jpg file referenced by filepath. But as even if I set it to have more bytes they are left as 0, I guess it contains the proper bytes.
But once the last instruction is executed bm is left as null.
What could I do so I can properly get the bitmap from that data?
PD: I'm aware it would be more logical to do:
Bitmap bm = BitmapFactory.decodeFile(filePath);
But, for some reason, that also returns null, so I'm taking this less direct approach to try to solve the issue.
After some investigation, I've checked that problem is that just a few bytes are the one being retrieved, with that, it's no brainer bitmpa ends up being null, what could I do so I get all bytes?

Related

Share an image using a memory stream or byte array

I have some standard code to share an image in my Android app. The image exists on the storage and I provide an URI to the image. This all works fine.
However, this requires the WRITE_EXTERNAL_STORAGE permission. Is there a way I can share an image without the need of this permission, for example, to not save the image to storage, but specifying a memory stream or byte array?
Thanks!
You can convert an image file to a byte array with the following code, which I taken from an answer to a similar question: How to convert image into byte array and byte array to base64 String in android?
String filepath = "/sdcard/temp.png";
File imagefile = new File(filepath);
FileInputStream fis = null;
try {
fis = new FileInputStream(imagefile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap bm = BitmapFactory.decodeStream(fis);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 100 , baos);
byte[] b = baos.toByteArray();
Optional step to encode in Base64
encImage = Base64.encodeToString(b, Base64.DEFAULT);

Which is the best way to upload multiple images to the server in android

I am using okHttp to upload multiple images(more than 10 in this case) to the server using multipartbody.
I and my friend had argument, I am saying to upload all images in a single request.
He is saying send one request at a time once the previous image is uploaded upload next one.
Which is the right thing to do, so the server works fast and no timeout occurs.
You can send Base64 format (String) like below and create one text file that contains all encoded photo as string
/**
* Encodes the image to Base64.
*/
private String encodeImage(String photoPath) {
File imagefile = new File(photoPath);
FileInputStream fis = null;
try {
fis = new FileInputStream(imagefile);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
Bitmap bm = BitmapFactory.decodeStream(fis);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.JPEG, 80, baos);
byte[] b = baos.toByteArray();
return Base64.encodeToString(b, Base64.DEFAULT);
}
and use MultipartUtility to upload file:
https://github.com/cloudinary/cloudinary_android/blob/master/Cloudinary/src/com/cloudinary/MultipartUtility.java

is it possible to convert .swf file to base64 format in java

I am trying to load a .swf file in my page, i would like to make this load faster by converting it to Base64, rather providing a src. This is working great with image formats by using the below code
Java code
BufferedImage buffImg = ImageIO.read(new File(imagePath));
ImageIO.write(buffImg, imgExtension, bos);
byte[] imageBytes = bos.toByteArray();
BASE64Encoder encoder = new BASE64Encoder();
imageString = encoder.encode(imageBytes);
but this is not working for swf file. is there any possible way to achieve this.
Html
<object width="10" height="10" data="data:application/x-shockwave-flash;base64, RldTCSEAAABIAZAAZAAADAEARBEIAAAAQwIAAP9AAAAA"></object>
thanks in advance.
Trying to get the file in base64 will not speed up the file transfer, it's just the opposite as it will convert the file which is stored in bytes (base256 if it can be said that way) to base64 (64 printable characters), so the final amount of data you will be transfering is more.
The only "win" is that you might be able to load it as part of the page instead of the browser making another call for the swf file, which should be no issue on http 1.1.
Unless you have some other good reason to do this, I would not suggest this kind of practice.
If you have your swf file(s) in a database as a blob, you could just make a servlet which sets the proper contenttype and write the whole file with the ServletOutputStream, without any tags. In your html code, you would have to reference to the servlet instead of a fixed file.
If you still want to convert the file to base64, you shouldn't use some image API, but get the file in a standard way for binary files, here's a sample that should do the job:
http://www.javapractices.com/topic/TopicAction.do?Id=245
You can still do the encoding as you did it once you have a byte array:
File file = new File(imagePath);
log("File size: " + file.length());
byte[] result = null;
try {
InputStream input = new BufferedInputStream(new FileInputStream(file));
result = readAndClose(input);
}
catch (FileNotFoundException ex){
log(ex);
}
BASE64Encoder encoder = new BASE64Encoder();
imageString = encoder.encode(result);
And the readAndClose method:
byte[] readAndClose(InputStream aInput){
byte[] bucket = new byte[32*1024];
ByteArrayOutputStream result = null;
try {
try {
result = new ByteArrayOutputStream(bucket.length);
int bytesRead = 0;
while(bytesRead != -1){
bytesRead = aInput.read(bucket);
if(bytesRead > 0){
result.write(bucket, 0, bytesRead);
}
}
}
finally {
aInput.close();
}
}
catch (IOException ex){
log(ex);
}
return result.toByteArray();
}
This should do the trick, maybe some fine tunings to adapt the code to your specific situation, optimize it and better error handling...

Read first bytes of a file

I need a very simple function that allows me to read the first 1k bytes of a file through FTP. I want to use it in MATLAB to read the first lines and, according to some parameters, to download only files I really need eventually. I found some examples online that unfortunately do not work. Here I'm proposing the sample code where I'm trying to download one single file (I'm using the Apache libraries).
FTPClient client = new FTPClient();
FileOutputStream fos = null;
try {
client.connect("data.site.org");
// filename to be downloaded.
String filename = "filename.Z";
fos = new FileOutputStream(filename);
// Download file from FTP server
InputStream stream = client.retrieveFileStream("/pub/obs/2008/021/ab120210.08d.Z");
byte[] b = new byte[1024];
stream.read(b);
fos.write(b);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (fos != null) {
fos.close();
}
client.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
}
the error is in stream which is returned empty. I know I'm passing the folder name in a wrong way, but I cannot understand how I have to do. I've tried in many way.
I've also tried with the URL's Java classes as:
URL url;
url = new URL("ftp://data.site.org/pub/obs/2008/021/ab120210.08d.Z");
URLConnection con = url.openConnection();
BufferedInputStream in =
new BufferedInputStream(con.getInputStream());
FileOutputStream out =
new FileOutputStream("C:\\filename.Z");
int i;
byte[] bytesIn = new byte[1024];
if ((i = in.read(bytesIn)) >= 0) {
out.write(bytesIn);
}
out.close();
in.close();
but it is giving an error when I'm closing the InputStream in!
I'm definitely stuck. Some comments about would be very useful!
Try this test
InputStream is = new URL("ftp://test:test#ftp.secureftp-test.com/bookstore.xml").openStream();
byte[] a = new byte[1000];
int n = is.read(a);
is.close();
System.out.println(new String(a, 0, n));
it definitely works
From my experience when you read bytes from a stream acquired from ftpClient.retrieveFileStream, for the first run it is not guarantied that you get your byte buffer filled up. However, either you should read the return value of stream.read(b); surrounded with a cycle based on it or use an advanced library to fill up the 1024 length byte[] buffer:
InputStream stream = null;
try {
// Download file from FTP server
stream = client.retrieveFileStream("/pub/obs/2008/021/ab120210.08d.Z");
byte[] b = new byte[1024];
IOUtils.read(stream, b); // will call periodically stream.read() until it fills up your buffer or reaches end-of-file
fos.write(b);
} catch (IOException e) {
e.printStackTrace();
} finally {
IOUtils.closeQuietly(inputStream);
}
I cannot understand why it doesn't work. I found this link where they used the Apache library to read 4096 bytes each time. I read the first 1024 bytes and it works eventually, the only thing is that if completePendingCommand() is used, the program is held for ever. Thus I've removed it and everything works fine.

Line by line image swing

I want to show an image as it is downloading, I have the URL, and I am trying to get the image parts like this:
InputStream openStream = url.openStream();
DataInputStream dis = new DataInputStream(new BufferedInputStream(openStream));
ByteArrayOutputStream os = new ByteArrayOutputStream();
while ((s = dis.read(b)) != -1) {
os.write(b , 0, s);
support.firePropertyChange("stream", null, os);
}
This way, any listener get the stream and creates an image, this way:
if("stream".equals(evt.getPropertyName())){
try {
ByteArrayOutputStream stream = (ByteArrayOutputStream) evt.getNewValue();
byte[] byteArray = stream.toByteArray();
stream.flush();
Image createImage = Toolkit.getDefaultToolkit().createImage(byteArray);
this.getContentPane().add(new JLabel(new ImageIcon(createImage)));
} catch (IOException ex) {
Logger.getLogger(ImageTest.class.getName()).log(Level.SEVERE, null, ex);
}
}
However, I am getting a "Premature end of JPEG file sun.awt.image.ImageFormatException: JPEG datastream contains no image" error, the image is a JPG image format, is there any library or method known to make something similar?
It would depend on the image decoder, but you could try ImageObserver. There's an example in Tracking Image Loading: MediaTracker and ImageObserver.

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