阅读蓝牙套接字android后写一个输出流

Question

我想从设备读取后（通过Bluetooth套接字）进行写入问题是，当套接字关闭时，while（true）完成，因此我无法再次写入。

这是代码：

        try {
            // This will block until it succeeds in connecting to the device
            // through the bluetoothSocket or throws an exception
            bluetoothSocket.connect();
            try {
                connectingThread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            outstream = bluetoothSocket.getOutputStream();
            outstream.write("P".getBytes());
            instream = bluetoothSocket.getInputStream();
            byte[] buffer = new byte[128];  // buffer store for the stream
            int bytes; // bytes returned from read()
            String readMessage = "";

             // Keep listening to the InputStream until an exception occurs
            while (true) {
                try {
                    // Read from the InputStream
                    bytes = instream.read(buffer);
                    if(bytes!= -1){
                    // Send the obtained bytes to the UI activity
                    readMessage = new String(buffer, 0, bytes);

                    arrayList.add(readMessage);
                    biodyMsg = TextUtils.join("", arrayList);
                    }

                } catch (Exception e) {

                    Log.d("Read Error", e.toString());

                }finally {
                    outstream = bluetoothSocket.getOutputStream();
                    outstream.write("F".getBytes());
                }
                break;
            }

        } catch (IOException connectException) {
            connectException.printStackTrace();
            try {    
                bluetoothSocket.close();
            } catch (IOException closeException) {
                closeException.printStackTrace();
            }
        }

Logcat

你能帮助我吗

Answer 1

while (true)循环终止的唯一方法是通过break语句或获取未捕获的异常，并且您没有提到获取一个。 此代码中有两个可能的例外：

• IOException ：但是，使用此代码获取IOException的唯一方法是对等方重置连接。
• 构造String ，如果bytes为负，则为ArrayIndexOutOfBoundsException ，可以为： 但是您也没有提到这一点。

您的实际问题是您没有检查-1的bytes ，这表示流结束，而这又表明对等体已关闭连接，这反过来又表明您应关闭套接字并断开连接。读取循环。