Robospice-addListenerIfPending-如何知道是否找到请求? [英] Robospice - addListenerIfPending - how do I know if request WAS found?

问题描述

我正在尝试使用robospice实现一个非常简单的案例:一个登录屏幕.单击登录按钮后，将显示加载动画并使用SpiceManager.execute(..)发出请求(当然，不进行缓存.由于这是一个登录请求，因此每次都需要对服务器进行实际调用).

I am trying to implement a very simple case using robospice: a login screen. When login button is clicked, loading animation is shown and request is made using SpiceManager.execute(..) (without caching, of course. Since it's a login request, I need to do actual call to the server every time).

因此，要处理屏幕旋转等问题，在Activity.onStart()中，我应该使用SpiceManager.addListenerIfPending(..)，如果请求实际上是未决的，我应该显示加载动画而不进行任何实际的请求.

So, to handle screen rotations, etc., in Activity.onStart() I should use SpiceManager.addListenerIfPending(..), and if request is actually pending, I should show loading animation without doing any real request.

问题是:PendingRequestListener没有onRequestExists()方法.它只有onRequestNotFound().

The problem is: PendingRequestListener does not have onRequestExists() method. It only has onRequestNotFound().

一种可能(但不令人满意)的解决方案是始终绘制加载屏幕，然后调用addListenerIfPending(..)，然后在onRequestNotFound()中删除加载动画.如果没有真正的请求，这将创建闪烁"的加载屏幕，这看起来真的很糟糕.实现所需行为的正确方法是什么?

One possible (but unsatisfactory) solution, is to draw loading screen always, then call addListenerIfPending(..), and then remove loading animation in onRequestNotFound(). This creates "flickering" loading screen if there was no real request, which looks really bad. What is the proper way of implementing desired behavior?

推荐答案

好吧，以防google领导这里的任何人. 正确的解决方案: 实际上，该功能已在库中.当等待请求被发现时，有一种方法会被调用，它只会执行任何操作.

Ok, in case google leads anyone here. Proper solution: in reality, this functionality is already in the library. There is a method which gets called when pending request WAS found, it just does... nothing.

您需要:

1. 创建扩展PendingRequestListener的自己的界面:

public interface MyPendingRequestListener<T> extends PendingRequestListener<T> {
    void onRequestAggregated();
}

注意:通过Robospice进行请求时，您将需要使用实现此接口的请求侦听器.

Note: you will need to use request listeneres implementing this interface when doing requests through Robospice.

创建实现RequestListenerNotifier的自己的类.我通过复制粘贴DefaultRequestListenerNotifier(由于方法post(..)是私有的，所以无法扩展它)来完成此操作，因为它包含针对其他情况的porper通知实现.例如，MyRequestListenerNotifier.

Create your own class implementing RequestListenerNotifier. I did this by copy-pasting DefaultRequestListenerNotifier (I was not able to extend it because method post(..) is private) because it contains porper notification implementation for other cases. For example, MyRequestListenerNotifier.

覆盖方法notifyListenersOfRequestAggregated:

@Override
public <T> void notifyListenersOfRequestAggregated(final CachedSpiceRequest<T> request, Set<RequestListener<?>> listeners) {
    post(new AggregatedRunnable(listeners), request.getRequestCacheKey());
}

private static class AggregatedRunnable implements Runnable {
    private final Set<RequestListener<?>> listeners;

    public AggregatedRunnable(final Set<RequestListener<?>> listeners) {
        this.listeners = listeners;
    }

    @Override
    public void run() {

        if (listeners == null) {
            return;
        }

        Ln.v("Notifying " + listeners.size() + " listeners of request aggregated");
        synchronized (listeners) {
            for (final RequestListener<?> listener : listeners) {
                if (listener != null && listener instanceof MyPendingRequestListener) {
                    Ln.v("Notifying %s", listener.getClass().getSimpleName());
                    ((MyPendingRequestListener<?>) listener).onRequestAggregated();
                }
            }
        }
    }
}

扩展SpiceService并覆盖以下方法(您将需要使用此自定义服务而不是标准的robospice服务):

Extend SpiceService and override the following method (you will need to use this customized service instead of standard robospice service):

protected RequestListenerNotifier createRequestRequestListenerNotifier() {
    return new MyRequestListenerNotifier();
}

就是这样.现在，当您使用addListenerIfPending时，如果找到待处理的请求，就会调用onRequestAggregated().

That's it. Now, when you use addListenerIfPending, onRequestAggregated() will be called when pending request IS found.

重要说明::仅当您在执行请求时使用Cache键时，此选项才有效.例如，您可以使用空字符串(但不 null)作为缓存键.

IMPORTANT NOTE: This will only work when you use Cache key when doing request. For example, you can use empty string (but NOT null) as cache key.

示例:

//doing request for the first time
spiceManager.execute(request, "", DurationInMillis.ALWAYS_EXPIRED, requestListener);
//...     
//checking if request is pending e.g. when activity is restarted
spiceManager.addListenerIfPending(responseClass, "", requestListener);

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