Question

我需要根据从蓝牙rfcomm频道

收到的数据更新TextView

这是rfcomm处理函数：

// The Handler that gets information back from the BluetoothChatService
private final Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {

        txtViewDebug = (TextView) findViewById(R.id.txtView_textViewDebug);
        switch (msg.what) {
            case MESSAGE_STATE_CHANGE:
                if(D) Log.i(TAG, "MESSAGE_STATE_CHANGE: " + msg.arg1);
                switch (msg.arg1) {
                    case BluetoothChatService.STATE_CONNECTED:
                        // mTitle.setText(R.string.title_connected_to);
                        // mTitle.append(mConnectedDeviceName);
                        mConversationArrayAdapter.clear();
                        break;
                    case BluetoothChatService.STATE_CONNECTING:
                        //  mTitle.setText(R.string.title_connecting);           // ORIGINALLY PRESENT
                        break;
                    case BluetoothChatService.STATE_LISTEN:
                    case BluetoothChatService.STATE_NONE:
                        // mTitle.setText(R.string.title_not_connected);        // ORIGINALLY PRESENT
                        // mTitle.setText(R.string.not_connected);
                        break;
                }
                break;
            case MESSAGE_WRITE:
                byte[] writeBuf = (byte[]) msg.obj;
                // construct a string from the buffer
                String writeMessage = new String(writeBuf);
                mConversationArrayAdapter.add("Me:  " + writeMessage);
                break;
            case MESSAGE_READ:
                byte[] readBuf = (byte[]) msg.obj;
                // construct a string from the valid bytes in the buffer
                String readMessage = new String(readBuf, 0, msg.arg1);
                switch(rfcomm_state_flag){
                    case 0:
                        mConversationArrayAdapter.add(mConnectedDeviceName+":  " + readMessage);
                        break;

                    case 1:
                        // current received data is the lower half of the CSR audio signal
                        for(int i=0; i<AUDIO_FRAME_SIZE; i++){
                            audio_sig_from_csr[i] = (short) readMessage.charAt(i);
                            // txtViewDebug.append(Integer.toHexString(audio_sig_from_csr[i] & 0xffff)  + "\n" ) ;
                            // txtViewDebug.setText(txtViewDebug.getText() + Integer.toHexString(audio_sig_from_csr[i] & 0xffff)  + "\n" );
                        }
                        txtViewDebug.append("Test value" + "\n") ;
                        // txtViewDebug.invalidate();

                        break;

                    case 2:
                        // current received data is the upper half of the CSR audio signal
                        rfcomm_state_flag = 0;      // reset this flag to 0
                        for(int i=0; i<AUDIO_FRAME_SIZE; i++){
                            tempVar = (short) readMessage.charAt(i);
                            audio_sig_from_csr[i] += (tempVar << 8);
                        }

                        try {
                            for(int i=0;i <audio_sig_from_csr.length; i++)
                                // savToDisk.writeShort(Short.reverseBytes(lin[i]));        // from wav file creator file
                                savToDisk.writeShort(audio_sig_from_csr[i] );
                            // payload += lin.length; // use this line if lin is an array of byte
                            // payload = payload + (lin.length)*2;
                            fd.sync();
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                        Toast.makeText(BluetoothChat.this, "File written", Toast.LENGTH_LONG).show();
                        break;
                }

                break;
            case MESSAGE_DEVICE_NAME:
                // save the connected device's name
                mConnectedDeviceName = msg.getData().getString(DEVICE_NAME);
                Toast.makeText(getApplicationContext(), "Connected to "
                        + mConnectedDeviceName, Toast.LENGTH_SHORT).show();
                break;
            case MESSAGE_TOAST:
                Toast.makeText(getApplicationContext(), msg.getData().getString(TOAST),
                        Toast.LENGTH_SHORT).show();
                break;
        }
    }
};

该项目本身基于Android开发者网站的蓝牙聊天示例程序。我修改了蓝牙聊天程序，以便从自定义蓝牙设备发送和接收rfcomm数据

case MESSAGE_READ:

是来自蓝牙设备的传入rfcomm数据以字节

的形式接收的地方

我将字节values更改为String，然后更改为short，我想在TextView中将其显示为十六进制值，以比较我从rfcomm频道获取的内容是否为蓝牙设备发送的相同值

我可以在case 1:

中的case MESSAGE_READ:下看到我更新TextView的尝试

但是，TextView不会更新是否调用append（）函数的setText（）函数。

该行

txtViewDebug = (TextView) findViewById(R.id.txtView_textViewDebug);

在onCreate()，但那也没有用。

我在阅读here之后尝试致电invalidate()，但这不起作用

为什么不从此处理程序函数内部更新TextView？我在我的界面添加了另一个命令按钮，并添加了一个简单的txtViewDebug.setText()，它按预期工作，但我需要能够使用我在此处理函数中收到的值更新它。

为什么没有TextView更新，我该如何解决这个问题？

Answer 1

必须在ui线程上设置文本所以尝试将代码包装在runOnUiThread

中

TextView未在RFCOMM处理程序

1 个答案: