蓝牙文件传输安卓 [英] Bluetooth file transfer Android

问题描述

我在通过蓝牙套接字发送大文件时遇到问题.较小的文件可以正确传输.我相信最多可以正确传输 161280 个字节.

I am facing a problem in sending large files over bluetooth sockets. Smaller files get transferred correctly. I believe upto 161280 bytes get transferred correctly.

我进行了更多测试并缩小了原因.看来

I did some more testing and narrowed down the cause. It seems that

outStream.write(mybytearray, 0, mybytearray.length);

在发送代码部分写入的字节数不超过 161280 个字节.我通过不关闭套接字连接看到了这种行为，从而导致接收部分中的 read 在 161280 字节上阻塞".这里的蓝牙输出流有什么问题?我做错了什么?

in the sending code part is NOT writing more than 161280 bytes. I saw this behavior by not closing the socket connection, thereby causing the read in the receiving part to "block" on 161280 bytes. What is wrong with the bluetooth output stream here? What am I doing wrong?

编辑 2:这样做可以让它通过.

for(int i = 0 ; i < mybytearray.length ; i++){
    outStream.write(mybytearray[i]);
}

发送代码:

    try {
        outStream = mBluetoothSocket.getOutputStream();
        Log.d(TAG,"outStream created success!");
    } catch (IOException e) {
        Log.d(TAG,
                "ON RESUME: Output stream creation failed.",
                e);
    }

    File myFile = new File(file_name);
    Log.d(TAG,"file /source.pdf created success!");

    byte[] mybytearray = new byte[(int)myFile.length()];
    Log.d(TAG,"file length() =" + (int)myFile.length());

    FileInputStream fis = new FileInputStream(myFile);
    Log.d(TAG,"fis created");

    BufferedInputStream bis = new BufferedInputStream(fis,1272254 );
    Log.d(TAG,"bis created success");

    bis.read(mybytearray,0,mybytearray.length);
    Log.d(TAG,"ALL Bytes read from bis");

    outStream.write(mybytearray, 0, mybytearray.length);
    Log.d(TAG,"BYTES WRITTEN to OUTSTREAM of socket");


    outStream.flush();
    Log.d(TAG,"bytes flushed");
    outStream.close();

接收代码:

// Attach the i/p stream to the socket
    try {
        InputStream in = socket.getInputStream();
        mIn = in;
        Log.d(TAG, "input stream acquired");

    } catch (IOException e1) {
        e1.printStackTrace();
    }
    // Create output streams & write to file
    FileOutputStream fos = new FileOutputStream(
            Environment.getExternalStorageDirectory()
                    + "/copy.pdf");
    try {
        bytesRead = mIn.read(buffer, 0, buffer.length);
        Log.d(TAG, "bytesRead first time =" + bytesRead);
        current = bytesRead;

        do {
            Log.d(TAG, "do-while -- current: " + current);
            bytesRead = mIn.read(buffer, current,
                    buffer.length - current);
            Log.d(TAG, "bytesRead: =" + bytesRead);

            if (bytesRead >= 0)
                current += bytesRead;
        } while (bytesRead > -1);
    } catch (IOException e) {
        e.printStackTrace();
        Log.d(TAG, "do while end:-- buffer len= "
                + buffer.length + "  current: " + current);

        fos.write(buffer);
        Log.d(TAG, "fos.write success! buffer: "
                + buffer.length + "  current: " + current);

        fos.flush();
        fos.close();
    }
}
socket.close();

Logcat:

D/ReceiveService( 5761): do-while -- current: 155232
D/ReceiveService( 5761): bytesRead: =1008
D/ReceiveService( 5761): do-while -- current: 156240
D/ReceiveService( 5761): bytesRead: =1008
D/ReceiveService( 5761): do-while -- current: 157248
D/ReceiveService( 5761): bytesRead: =1008
D/ReceiveService( 5761): do-while -- current: 158256
D/ReceiveService( 5761): bytesRead: =1008
D/ReceiveService( 5761): do-while -- current: 159264
D/ReceiveService( 5761): bytesRead: =1008
D/ReceiveService( 5761): do-while -- current: 160272
D/ReceiveService( 5761): bytesRead: =1008
D/ReceiveService( 5761): do-while -- current: 161280
W/System.err( 5761): java.io.IOException: Software caused connection abort
W/System.err( 5761):    at android.bluetooth.BluetoothSocket.readNative(Native Method)
W/System.err( 5761):    at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:307)
W/System.err( 5761):    at   android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:96)
W/System.err( 5761):    at com.bt.server.ReceiveService$AcceptThread.run(ReceiveService.java:141)

我使用的是摩托罗拉里程碑.安卓 2.1

I am using Motorola Milestone. Android 2.1

推荐答案

我能够通过将小块数据发送到蓝牙外流来解决这个问题.结果证明 8 * 1024 是一个很好的缓冲区大小，这有助于通过流无缝发送数据以及防止接收端的数据损坏.

I was able to solve this problem by sending small chunks of data out to the bluetooth outstream. It turned out that 8 * 1024 was a good buffer size, which helped in sending out data seamlessly over the stream as well as preventing corruption of data at the receiving end.

BufferedInputStream bis = new BufferedInputStream(fis, 8 * 1024);


byte[] buffer = new byte[8192];
int len
while ((len = bis.read(buffer)) != -1) {
    outStream.write(buffer, 0, len);
}

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