android - 为什么 TextView 无法显示来自串行蓝牙的任何数据？

Question

我需要TextView从串行显示数据Bluetooth。但是当我将我的应用程序与串行设备连接时，它确实连接但突然被强制关闭。logcat 什么也没显示，所以我不知道出了什么问题。

这是应用程序inputstream在连接时侦听的代码：

public void run() {
    Log.i(TAG, "BEGIN mConnectedThread");
    byte[] buffer = new byte[1024];
    int bytes;

    while (true) {
        try {

            // Read from the InputStream
            bytes = mmInStream.read(buffer);

            //mEmulatorView.write(buffer, bytes);

            mTextView.append(new String(buffer));
            // Send the obtained bytes to the UI Activity
            //mHandler.obtainMessage(BlueTerm.MESSAGE_READ, bytes, -1, buffer).sendToTarget();

            String a = buffer.toString();
            mTextView.setText(a);
            a = "";
        } catch (IOException e) {
            Log.e(TAG, "disconnected", e);
            connectionLost();
            break;
        }
    }
}

并且TextView mTextView = (TextView) findViewById(R.id.dataTerm);
在布局上：

<TextView
    android:id="@+id/dataTerm"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

那么有人知道出了什么问题吗？任何答案都非常有帮助，谢谢..

最终工作的代码

1. 在主文件上，在我的例子中名为 FinalSetting：
   在 Activity 方法上，声明：

   //Layout View   
   private static TextView mTextView;
   

   在onCreate(Bundle savedInstanceState)方法上声明textview：

   mTextView = (TextView) findViewById(R.id.dataTerm);
   

   关于Handler方法：

   case MESSAGE_READ:
       byte[] readBuf = (byte[]) msg.obj;              
       //mEmulatorView.write(readBuf, msg.arg1);
       // construct a string from the valid bytes in the buffer
       String readMessage = new String(readBuf, 0, msg.arg1);
       //mConversationArrayAdapter.add(mConnectedDeviceName+":  " + readMessage);
       mTextView.setText(readMessage);
       break;
   

2. 关于BluetoothService.java文件：
   让我们直接进入方法

   //This thread runs during a connection with a remote device.
   //It handles all incoming and outgoing transmissions.
   
   private class ConnectedThread extends Thread {
       private final BluetoothSocket mmSocket;
       private final InputStream mmInStream;
       private final OutputStream mmOutStream;
   
       public ConnectedThread(BluetoothSocket socket) {
           Log.d(TAG, "create ConnectedThread");
           mmSocket = socket;
           InputStream tmpIn = null;
           OutputStream tmpOut = null;
   
           // Get the BluetoothSocket input and output streams
           try {
               tmpIn = socket.getInputStream();
               tmpOut = socket.getOutputStream();
           } catch (IOException e) {
               Log.e(TAG, "temp sockets not created", e);
           }
           mmInStream = tmpIn;
           mmOutStream = tmpOut;
       }
   
       public void run() {
           Log.i(TAG, "BEGIN mConnectedThread");
           byte[] buffer = new byte[1024];
           //final byte[] buffer = new byte[1024];
           int bytes;
   
           // Keep listening to the InputStream while connected
           while (true) {
               try {
                   // Read from the InputStream
                   bytes = mmInStream.read(buffer);
   
                   //Send the obtained bytes to the UI Activity
                   mHandler.obtainMessage(FinalSetting.MESSAGE_READ, bytes, -1, buffer).sendToTarget();
               } catch (IOException e) {
                   Log.e(TAG, "disconnected", e);
                   connectionLost();
                   break;
               }
           }
       }
   
       /**
       * Write to the connected OutStream.
       * @param buffer  The bytes to write
       */
       public void write(byte[] buffer) {
           try {
               mmOutStream.write(buffer);
   
               // Share the sent message back to the UI Activity
               mHandler.obtainMessage(FinalSetting.MESSAGE_WRITE, buffer.length, -1, buffer).sendToTarget();
           } catch (IOException e) {
               Log.e(TAG, "Exception during write", e);
           }
       }
   
       public void cancel() {
           try {
               mmSocket.close();
           } catch (IOException e) {
               Log.e(TAG, "close() of connect socket failed", e);
           }
       }    
   }
   

连接到串行Bluetooth设备后，数据将显示在TextView. 希望这有帮助：D

Answer 1

似乎您正在尝试在非 UI 线程中修改mTextView ，这是非法的，可能是 FC 的原因（如果不是任何其他问题）。但是，您可以按如下方式实现：

改变这个：

mTextView.append(new String(buffer));

对此：

mTextView.post(new Runnable() {
    @Override
    public void run() {
        mTextView.append(new String(buffer));
    }
});