Question

我一直在创建一个蓝牙应用程序，一切正常，从打开和关闭，搜索设备，可见设备，打开服务器，设置客户端。一切正常，设备可以配对。但是当我想使用Input / OutputStream执行数据传输时，崩溃就开始了。

代码没有错误，但在执行connectedThread功能时崩溃了。这是代码

private class ConnectedThread extends Thread {

    private final BluetoothSocket mySocket;
    private final InputStream myInStream;
    private final OutputStream myOutStream;

    public ConnectedThread(BluetoothSocket socket) {
        mySocket = socket;
        InputStream tmpIn = null;
        OutputStream tmpOut = null;
        try {
            tmpIn = socket.getInputStream();
            tmpOut = socket.getOutputStream();
        } catch (IOException e) {
        }

        myInStream = tmpIn;  <-------MainActivity.Java:623
        myOutStream = tmpOut;
    }

    public void run() {
        byte[] buffer = new byte[1024];
        int begin = 0;
        int bytes = 0;
        while (true) {
            try {
                bytes += myInStream.read(buffer, bytes, buffer.length - bytes);
                for (int i = begin; i < bytes; i++) {
                    if (buffer[i] == "#".getBytes()[0]) {
                        myHandler.obtainMessage(1, begin, i, buffer).sendToTarget();
                        begin = i + 1;
                        if (i == bytes - 1) {
                            bytes = 0;
                            begin = 0;
                        }
                    }
                }
            } catch (IOException e) {
                break;
            }
        }
    }

    public void write(byte[] bytes) {
        try {
            myOutStream.write(bytes);
        } catch (IOException e) {
        }
    }

    public void cancel() {
        try {
            mySocket.close();
        } catch (IOException e) {
        }
    }


    Handler myHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            byte[] writeBuf = (byte[]) msg.obj;
            int begin = (int) msg.arg1;
            int end = (int) msg.arg2;

            switch (msg.what) {
                case 1:
                    String writeMessage = new String(writeBuf);
                    writeMessage = writeMessage.substring(begin, end);
                    break;
            }
        }
    };

}

connectedThread从这里被激活

transferBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ConnectedThread t = new ConnectedThread(socket);<------MainActivity.Java:192
                t.start();
        });

Logcat显示此

07-14 02：53：04.937 16812-16812 / com.example.heszrave.bluetoothremote E / AndroidRuntime：FATAL EXCEPTION：main 显示java.lang.NullPointerException 在com.example.heszrave.bluetoothremote.MainActivity $ ConnectedThread。（MainActivity.java:623）在com.example.heszrave.bluetoothremote.MainActivity $ 6.onClick（MainActivity.java:192）

当我点击MainActivity.Java:623时，它指向myInStream = tmpIn;的MainActivity.Java:192它指向了触发事件ConnectedThread t = new ConnectedThread(socket);

执行功能时代码没有错误但应用程序崩溃。 Logcat显示FATAL EXCEPTION（MainActivity.java:623)

0 个答案: