Question

我正在重写库中的方法以利用Rx。下面的代码示例是原始方法。

public void connect(ConnectionListener connectionListener) {

    //......

    RxBleDevice device = mRxBleClient.getBleDevice(builder.toString());

    mEstablishedConnection = device.establishConnection(mContext, false)
            .observeOn(AndroidSchedulers.mainThread())
            .doOnError(throwable -> {
                throwable.printStackTrace();
                connectionListener.onFailed();
                Log.d(TAG, "Error establishing a connection" + throwable.getMessage());
            })
            .subscribe(rxBleConnection -> {
                mConnection = rxBleConnection;
                connectionListener.onConnected();
                setNotifications();
                Log.d(TAG, "Connection established. Status: " + device.getConnectionState().toString());
            }, throwable -> {
                if (throwable != null) {
                    throwable.printStackTrace();
                }
            });
}

我的第一步是返回Subscription而不是将其保存到mEstablishedConnection。这将允许用户取消订阅以触发断开连接：

public Subscription connect() {

    //..

    RxBleDevice device = mRxBleClient.getBleDevice(builder.toString());

    return device.establishConnection(mContext, false)
            .observeOn(AndroidSchedulers.mainThread())
            .doOnError(throwable -> {
                throwable.printStackTrace();
                Log.d(TAG, "Error establishing a connection" + throwable.getMessage());
            })
            .flatMap(rxBleConnection -> {
                mConnection = rxBleConnection;
                return Observable.empty();
            })
            .subscribe(o -> {
                setNotifications();
                Log.d(TAG, "Connection established. Status: " + device.getConnectionState().toString());
            }, throwable -> {
                if (throwable != null) {
                    throwable.printStackTrace();
                }
            });
}

上面的问题是我无法正确地将错误传播回调用者，这样做会很好。如何重写此方法以使其成为被动方式，让调用者收到错误，而不仅仅返回RxBleConnection，这是第三方类？

Answer 1

正确答案主要取决于您想要实现的界面。您可以将RxBleConnection包装在您自己的界面中。它可能是这样的：

public Observable<YourWrapperClass> connect() {
    RxBleDevice device = // ...
    return device.establishConnection(context, false)
        .doOnNext(connection -> {
            setNotifications(connection) // pass the connection to setNotifications()
            mConnection = connection // store the mConnection if it is a must - in the reactive approach objects are meant to be passed instead of stored 
        })
        .map(connection -> new YourWrapperClass(connection))
}

此处来电者将负责订阅Observable（因此可以取消订阅）并且不会知道内部（RxBleConnection）。

重写连接方法以利用Rx

1 个答案: