如何从 Application 类正确关闭 WebSockets？

Question

我在 android 中的聊天应用程序中使用 WebSockets。为了方便起见，我在 Application 类中创建连接，以便它可以由具有一个实例的活动和片段使用。这是我的应用程序类的代码：

public class Main extends Application implements LifecycleObserver {

    private static WeakReference<Context> context;
    private WebSocket webSocket;
    private final Request request;
    private final OkHttpClient client;
    public static final int SOCKET_CLOSE_CODE = 1000;

    @Override
    public void onCreate() {
        super.onCreate();
        context = new WeakReference<>(getApplicationContext());
        ProcessLifecycleOwner.get().getLifecycle().addObserver(this);
        this.client = new OkHttpClient();
        this.request = new Request.Builder().url("ws://192.168.1.9:8080").build();
    }

    public void connect() {
        webSocket = client.newWebSocket(request, new WebSocketListener() {
            @Override
            public void onOpen(WebSocket webSocket, Response response) {
                super.onOpen(webSocket, response);
            }

            @Override
            public void onMessage(WebSocket webSocket, String text) {
                super.onMessage(webSocket, text);
            }

            @Override
            public void onMessage(WebSocket webSocket, ByteString bytes) {
                super.onMessage(webSocket, bytes);
            }

            @Override
            public void onClosing(WebSocket webSocket, int code, String reason) {
                super.onClosing(webSocket, code, reason);
            }

            @Override
            public void onClosed(WebSocket webSocket, int code, String reason) {
                super.onClosed(webSocket, code, reason);
            }

            @Override
            public void onFailure(WebSocket webSocket, Throwable t, Response response) {
                super.onFailure(webSocket, t, response);
            }
        });
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
    public void onResume() {
        if (webSocket == null) return;
        connect();
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
    public void onPause() {
        if (webSocket == null) return;
        disconnect();
    }
    
    private void disconnect() {
      webSocket.close(SOCKET_CLOSE_CODE, null);
      webSocket = null;
    }


    @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
    public void onDestroy() {
        if (client == null) return;
        client.connectionPool().evictAll();
        client.dispatcher().executorService().shutdown();
    }
}

由于某种原因，套接字在 onPause 或 onDestroy 中都没有关闭（都尝试过）。我在服务器端使用 Ratchet。这段代码有什么问题？请注意，我想完全从应用程序类本身关闭连接，而不是从活动或片段或任何其他组件关闭连接。

Answer 1

答案可能是WebSocketActivity extends FragmentActivity implements WebSocketListener {}因为Activity会实现这些生命周期方法，因此它们可以被重写。