android - 从 Activity 中设置线程类中的文本

Question

我有两个类，一个是Activity，一个是Thread类:

Activity :

public class MainActivity extends AppCompatActivity {

    ObjectInputStream inFromServer = null;
    ObjectOutputStream outToServer=null;
    Socket clientSocket = null;
    String userName;

    EditText message;
    static TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);

        message = (EditText)findViewById(R.id.txtMessage);
        textView = (TextView)findViewById(R.id.textView);

        try {
            clientSocket = new Socket("10.0.0.41", 10002);

            outToServer =
                    new ObjectOutputStream(clientSocket.getOutputStream());

            inFromServer =
                    new ObjectInputStream((clientSocket.getInputStream()));

        } catch (IOException e) {
            e.printStackTrace();
        }

        ReceiveMessages receiveMessages = new ReceiveMessages(inFromServer);
        receiveMessages.start();
    }

    public void onClickSend(View view) throws IOException {
        outToServer.writeObject("Eliran!" + message.getText().toString());
    }

    public void btnUserName(View view) throws IOException {
        EditText editText = (EditText)findViewById(R.id.userName);
        userName = editText.getText().toString();
        outToServer.writeObject(userName + "!");
    }
}

线程类:

public class ReceiveMessages extends Thread {

    ObjectInputStream inFromServer = null;

    public ReceiveMessages(ObjectInputStream inFromServer)
    {
        this.inFromServer = inFromServer;
    }

    public void run() {
        try {
            while (true) {
                String message = (String) inFromServer.readObject();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

我想在 Thread 类中的 Activity 的 TextView 中设置文本。我该怎么做？我认为 InflateLayout 没有帮助。

Answer 1

我会通过创建一个回调来解决这个问题，当从服务器接收到字符串时调用该回调。

interface ReceiveMessageListener {
    void onMessageReceived (String message);
}

然后让我的 Activity 实现接口(interface)并在 onMessageReceived 回调中设置文本。

@Override
public void onMessageReceived (String message) {
    runOnUiThread(new Runnable() {
        @Override
        public void run () {
            textView.setText(message);
        }
    });
}

您还必须更改 MessageReceive 类的构造函数以采用 MessageReceiveListener。

来自您的 Activity :

ReceiveMessages receive = new ReceiveMessages(input, this);