Edit*
I have successful on the client server. Now I am doing a file transferring between 2 emulators. The file did transfer between the emulators, but I notice that the file size received is not the same as the original file. For example, A.jpg size is 900KB, but the received file is less than 900KB. I checked the file transfer size, found that there were some data(byte) lost when transferring. How is this happening?
Here's the code:
Client (Send File)
File myFile = new File ("/mnt/sdcard/Pictures/A.jpg");
FileInputStream fis = new FileInputStream(myFile);
OutputStream os = socket.getOutputStream();
int filesize = (int) myFile.length();
byte [] buffer = new byte [filesize];
int bytesRead =0;
while ((bytesRead = fis.read(buffer)) > 0) {
os.write(buffer, 0, bytesRead);
//Log display exact the file size
System.out.println("SO sendFile" + bytesRead);
}
os.flush();
os.close();
fis.close();
Log.d("Client", "Client sent message");
socket.close();
Server (Receive File)
FileOutputStream fos = new FileOutputStream("/mnt/sdcard/Pictures/B.jpg");
#SuppressWarnings("resource")
BufferedOutputStream bos = new BufferedOutputStream(fos);
InputStream is = clientSocket.getInputStream();
byte[] aByte = new byte[1024];
int bytesRead;
while ((bytesRead = is.read(aByte)) != -1)
{
bos.write(aByte, 0, bytesRead);
//Log display few parts the file size is less than 1024. I total up, the lost size caused the file received is incomplete
System.out.println("SO sendFile" + bytesRead);
}
clientSocket.close();
*Edit 2
While I surfed around google, I found that .read(buffer) does not guarantee read the full size(byte) of the file. Hence, the received file always lost some bytes (like space, empty character). To solve this, send the file size first to inform the receiver, then only start transfer the file.
NetworkOnMainThreadException occurs because you have to use AsyncTask
NullPointerException occurs because you are trying to use PrintWriter with the result of Sockets. As you have got nothing with Sockets you get this error.
The NetworkOnMainThreadException tells you what you are doing wrong.
You need to put the network stuff into a separate Thread (or AsyncTask or similar).
You can not call any server operation on Main Thread in Android.
In Android O.S 4.0 and above this will directly cause to NetworkOnMainThreadException. You have 2 choices :
1) Either to use AsyncTask to call your every server operation.
2) Or Use User defined Thread for any type of server operation.
I was also struggling with this Exception, only in OS version above 4.0 devices, So you can not ignore these small needs of Android.
Related
In my application the user can choose a file using the chooser Intent, which will then be "imported" into the application and saved in internal storage for security reasons. This all worked fine and still does on some devices, but for example on the Google Pixel on Android 7.1.1 it only functions normally for the first 4-6 files and afterwards it acts very odd.
The performance was going down drastically so I checked my storage usage and found that it was continuously growing, although the file I was supposed to be saving was less than 1mb large. Importing a file would cause the amount of storage taken by my app to rise past 500mb and upward. I can't seem to find the cause for this.
The method I am using to save the files which is called in an async background task:
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
OutputStream fos = new FileOutputStream(file);
int size = 0;
InputStream fis = getContentResolver().openInputStream(uri);
try{
bis = new BufferedInputStream(fis);
bos = new BufferedOutputStream(fos);
byte[] buf = new byte[1024];
int len = 1024;
while((len = bis.read(buf,0,len)) != -1){
bos.write(buf,0,len);
size = size+1024;
Log.v("Bytes written",""+size);
}
}catch (IOException e){
e.printStackTrace();
}finally {
try{
if(bis != null) bis.close();
if(bos != null) bos.close();
if(fis != null) fis.close();
if(fos != null) fos.close();
}catch(IOException e){
e.printStackTrace();
}
}
return Uri.fromFile(file);
The Uri which this function returns is then saved in an SQLite Database to be used later.
I appreciate all kinds of tips as to where this memory usage could be coming from.
Btw, this did not result from an update on the phone nor from any changes in my code, as it was working the last time I tested it and I haven't changed anything since.
I see a couple of things to correct:
1) The signature of the write method doesn't seem correct, if you write from a buffer you should use write(buff, offset, length).
2) You read into the buffer once, so it should be enugh to write out the buffer once too.
3) If you need to read the the buffer more than once, and write out the values more than once, use a while, not a do while. You have no garantee that the read operation was succesfull.
Ref to write method in Android Developer
I had an additional method which would append an index to a file added multiple times eg. "file.pdf", "file1.pdf","file2.pdf". This method wasn't correct, leading to an endless loop of creating a new file and appending an index. I managed to fix the problem by changing this method to avoid looping.
In retrospect I should have included that in my question.
I am writting a app transfer file based Socket.When I transfer file less than 10 mb ,then no matter what happens.But when I transfer file over 20mb, then I get Out of Memory error and crash my app.
This is my code
RandomAccessFile aFile = new RandomAccessFile(path, "r");
FileChannel inChannel = aFile.getChannel();
ByteBuffer buffer = ByteBuffer.allocate(1024);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int n;
while ((n = inChannel.read(buffer)) > 0) {
buffer.flip();
total_length += n;
baos.write(buffer.array(), 0, n);
byte[] aaa = baos.toByteArray();
ObjectStream obstream = new ObjectStream("stream", aaa, session_request, total_length);
aaa=null;
outt.writeObject(obstream);
obstream = null;
baos.reset();
buffer.clear(); // do something with the data and clear/compact it.
}
inChannel.close();
aFile.close();
This is error that geted :
FATAL EXCEPTION: Thread-177
java.lang.OutOfMemoryError
at java.io.ByteArrayOutputStream.toByteArray(ByteArrayOutputStream.java:122)
at com.jsc.Remote2Droid.Thread.ThreadClientData.run(ThreadClientData.java:705)
out of memory at location:
byte[] aaa = baos.toByteArray();
Please help me fix my code.Thank all.Sorry for my english.
You are asking for troubles if you place such big files completely in memory before you send them.
So your approach is wrong.
You only need a small buffer. Then make a loop where you read chuncks from the file in the buffer and then write the bytes in that buffer to the output stream.
In this way it't irrelevant how big the file is.
I have an apk to download from a website. It works fine in Android 4, but when I downloaded it with an Android 5.0 device, I got the typical error:
Parse Error
There was a problem while parsing the package
Can anyone shed a bit of light on what is happening?
My server code to get the apk file (I don't want to place the apk file directly to download in website):
InputStream is = ApkDownloadController.class.getResourceAsStream("/apk/fileName.apk");
try {
response.addHeader("Content-Description", "File Transfer");
response.addHeader("Content-Type", " application/vnd.android.package-archive");
response.addHeader("Content-Disposition", "attachment; filename=apkName.apk");
response.addHeader("Content-Transfer-Encoding", "binary");
ServletOutputStream out = response.getOutputStream();
byte[] outputByte = new byte[4096];
// copy binary contect to output stream
while (is.read(outputByte, 0, 4096) != -1) {
out.write(outputByte, 0, 4096);
}
is.close();
out.flush();
out.close();
Thanks all!
I'm trying to send bmp image using socket. I have such code on android:
ByteArrayOutputStream stream = new ByteArrayOutputStream();
MainActivity.bmp.compress(Bitmap.CompressFormat.JPEG, 20,
stream);
byte[] byteArray = stream.toByteArray();
OutputStream os = echoSocket.getOutputStream();
os.write(byteArray,0,byteArray.length);
os.flush();
and on PC:
String q = SockIn.readLine();
File file = new File("filename.bmp");
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(q);
in bmp file I only get up to 401 bytes, which of course is corrupt bmp image. what am I doing wrong?
MODIFIED
modified PC side, now the code is:
InputStream in_ = clientSocket.getInputStream();
OutputStream out_ = new FileOutputStream("filename.bmp");
final byte[] buffer = new byte[1024];
int read = -1;
int i = 0;
while ((read = in_.read(buffer)) != -1) {
out_.write(buffer, 0, read);
System.out.println(i);
i++;
}
in_.close();
out_.close();
System.out.println("Done");
It never gets to last line( println("Done") ). when I close android program, it gets to last line and bmp opens succesfully
Your reading logic is completely off. You only use a readLine() once and then write that to file. The data that was written to the socket on the device side was binary. That means that trying to read it as if it were textual (as readLine() does) will return meaningless junk. The reason it's usually 401 bytes long is that readLine() will look for the first newline character combination and return everything up to that as a String. This is not what you want.
What you need is a loop that will read from the socket and write into the file as long as there is data in the socket. A standard copy loop should suffice here.
InputStream in = socket.getInputStream();
OutputStream out = new FileOutputStream(...);
final byte[] buffer = new byte[BUFFER_SIZE];
int read = -1;
while ((read = in.read(buffer)) != -1)
out.write(buffer, 0, read);
in.close();
out.close();
Note that the above code isn't tested but something to that effect should do the trick.
Why are you reading a String if you are sending a byte ?
Try those setp one by one only if the previous did not worked.
1. Read() and don't Readline() what you are writing
If you write a byte, read a byte
Byte obj = SockIn.read();
2. Encode your array before sending
Base64.encodeBase64String(byteArray);
So, I have a simple Android app that connects to a Java Server application using Sockets.
Specifically, I want to be able to send a file from the Server application to the Android app and then store that file in internal memory on the device.
The basis of the server code for transferring the file is:
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(new File(System.getProperty("user.home"), "text.txt")));
BufferedOutputStream bos = new BufferedOutputStream(clientSocket.getOutputStream());
byte buffer[] = new byte[1024];
int read;
while ((read = bis.read(buffer)) != -1) {
bos.write(buffer, 0, read);
}
bos.flush();
bos.close();
and the Client code to receive the file is as follows:
BufferedInputStream bis = new BufferedInputStream(clientSocket.getInputStream());
BufferedOutputStream bos = new BufferedOutputStream(openFileOutput("text.txt", Context.MODE_PRIVATE));
byte buffer[] = new byte[1024];
int read;
while ((read = bis.read(buffer)) != -1) {
bos.write(buffer, 0, read);
}
bos.flush();
bos.close();
The code appears to work fine when the client code is in a standard Java application, that is, the file sends successfully from server to client.
The problem arises when I use this code in an Android app. (Note: I use a standard FileOutputStream in the standard Java app instead of the
openFileOutput("text.txt", Context.MODE_PRIVATE))
line above).
For example purposes, the file I am transferring is a simple UTF-8 text file, which contains a single string
This is a text file.
However, when I pull this file I have copied to the emulator, from the "/data/data//files" folder on the emulator, there are an extra couple of bytes at the top of the file so the content is now
¨ÌThis is a text file.
I have no idea why this is happening and it has me stumped. I think the problem might be related to the line:
BufferedOutputStream bos = new BufferedOutputStream(openFileOutput("text.txt", Context.MODE_PRIVATE));
but I can't quite figure it out.
Any suggestions as to what I am doing wrong would be most helpful.
Thank you in advance