Question

在Android Studio中，我试图将一个字符串写入从WebSockets接收的TextView中。

我在onMessage方法中收到它，然后将其转发到我要编写它的MainActivity。

我的WebSocketListener：

import android.util.Log;
import okhttp3.Response;
import okhttp3.WebSocket;
import okhttp3.WebSocketListener;

public class CarWebSocketListener extends WebSocketListener {
    private static final int NORMAL_CLOSURE_STATUS = 1000;

    private String action;
    private String content;

    public CarWebSocketListener(String action, String content) {
        this.action = action;
        this.content = content;
    }

    @Override
    public void onOpen(WebSocket webSocket, Response response) {
        if(content.isEmpty()) {
            webSocket.send("{\"action\":\"" + action + "\"}");
        } else {
            webSocket.send("{\"action\":\"" + action + "\", \"content\": " + content + "}");
            Log.d("SETMODUS", "{\"action\":\"" + action + "\", \"content\": " + content + "}");
        }
        webSocket.close(NORMAL_CLOSURE_STATUS, "Closed");
    }

    @Override
    public void onMessage(WebSocket webSocket, String text) {
        MainActivity ma = new MainActivity();
        ma.setmTextSteer(text);
        Log.d("MonitorData", text);
    }

    @Override
    public void onClosing(WebSocket webSocket, int code, String reason) {
        webSocket.close(NORMAL_CLOSURE_STATUS, null);
        Log.i("CLOSED", code + " / " + reason);
    }

    @Override
    public void onFailure(WebSocket webSocket, Throwable t, Response response) {
        Log.e("FAILED", t.getMessage());
    }
}

这是我尝试编写它的地方（TextView称为mTextSteer）：

public void monitorCar(boolean getData) {
        if(getData) {
            mHandlerMonitoring = new Handler();
            mHandlerMonitoring.postDelayed(monitorRunnable, 500);
        } else {
            if(mHandlerMonitoring != null) {
                mHandlerMonitoring.removeCallbacks(monitorRunnable);
                mHandlerMonitoring = null;
            }
        }
    }

    Runnable monitorRunnable = new Runnable() {
        @Override
        public void run() {
            startWebSocket("getSteeringAngle", "");
            //startWebSocket("getSpeed", "");
            mHandlerMonitoring.postDelayed(this, 1000);
        }
    };

    public void setmTextSteer(final String text) {
        final int steer = Integer.parseInt(text);
        Log.d("SetTextOutside", ""+steer);
        //mTextSteer.setText(getString(R.string.steer_level, steer));
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Log.d("SetTextInside", ""+steer);
                mTextSteer.setText(getString(R.string.steer_level, steer));
            }
        });
    }

如果我现在查看我的Logcat，那么我只会一直看到SetTextOutSide：

2019-11-27 10:21:39.379 3625-3821/com.example.autonomesfahren D/SetTextOutside: 90

所以我想我永远也不会进入run（）方法。但是对于WebSocket，我需要在runOnUiThread中编写。我还尝试在runOnUiThread之外编写代码，因为您可以看到它的注释位置。如果我取消注释，则会收到以下消息：

2019-11-27 10:21:22.285 3625-3821/com.example.autonomesfahren E/FAILED: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference

将WebSockets接收到的数据写入TextView

0 个答案: