Question

之前已经讨论了很多次，但对我来说这仍然是一个真正的痛苦。

问题：每当我尝试将文本更新为TextView

时，应用程序崩溃

背景：我正在使用多线程的蓝牙应用程序。每当获得新消息时，“监听”线程（ConnectedThread）就发送Handler。然后在主Activity中解析此处理程序，其中初始化TextView。

我已经尝试过/检查过了什么：

我认为我没有从不同的活动/线程
在setContentView（R.layout.main）之后初始化TextView; （好吧，在其他帖子中，这造成了麻烦）

代码:(简而言之）

主要活动

 public class BluetoothActivity extends Activity {

 private TextView mDisplay;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        .....
        ..
    }


    private void setupApp() {

        // Initialize the BluetoothService to perform bluetooth connections
        // This is where the Handler is passed to "ConnectedThread" (it is part of    
           mService)
        mService = new BluetoothService(this, mHandler); 
    }


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

            ......

            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);
                if(D) Log.d(TAG, "Received: " + readMessage);

                mDisplay.setText(readMessage); <----- THIS IS THE ISSUE

                break;
                .......
                ....
            }
        }
    };

连接线

private class ConnectedThread extends Thread {

    ...... 

    public void run() {
        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(BluetoothActivity.MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch ...
            }
        }
    }

这主要是可以显示传入消息的功能

Toast.makeText(getApplicationContext(), "Received: " + readMessage,   
     Toast.LENGTH_SHORT).show();

Answer 1

解决

我忘了设置mDisplay =（TextView）findViewById（R.id.Display）;

TextView更新崩溃了应用程序

1 个答案: