Question

我有一个MainActivity，它有一个布尔变量mMonthlySubscribed。此活动有一个onPurchasesUpdated回调方法，该方法将true或false设置为mMonthlySubscribed变量。还有loadFragment方法在Fragments之间导航。

我的应用中有2个片段，分别为FragmentSubscribed和FragmentUnsubscribed。我如何通知mMonthlySubscribed值已更改为Fragment。

目前我正在检查mMonthlySubscribed值，并使用以下方法导航到相应的片段。当在MainActivity中触发onPurchasesUpdated回调并更改boolean mMonthlySubscribed时，我想从我的Fragments中调用以下方法之一。

((MainActivity) getActivity()).loadFragment(new FragmentUnsubscribed());

和

((MainActivity) getActivity()).loadFragment(new FragmentSubscribed());

简单来说，我的问题是当触发活动onPurchasesUpdated回调时，如何通知当前片段，以便我可以相应地调用上述方法。

MainActivity＆＃39>回调

    @Override
    public void onPurchasesUpdated(List<Purchase> purchaseList) {

        for (Purchase purchase : purchaseList) {
            if (purchase.getSku().equals(SKU_MONTHLY)) {
                Toast.makeText(getApplicationContext(), "Subscription is valid! - server", Toast.LENGTH_SHORT).show();
                mMonthlySubscribed = true;
            } else {
                Toast.makeText(getApplicationContext(), "Subscription is invalid! - server", Toast.LENGTH_SHORT).show();
                mMonthlySubscribed = false;
            }
        }
        // save state 
        saveSubscriptionStateSharedPreference();

        // todo : notify the current state to the fragment

    }

MainActivity的导航方法

public void loadFragment(Fragment fragment) {
    // load passed fragment within the frame_container of activity_main
    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.frame_container, fragment);
    transaction.commit();
}

Answer 1

据我所知，你可以试试这个：

 public void onPurchasesUpdated(List<Purchase> purchaseList) {

        for (Purchase purchase : purchaseList) {
            if (purchase.getSku().equals(SKU_MONTHLY)) {
                Toast.makeText(getApplicationContext(), "Subscription is valid! - server", Toast.LENGTH_SHORT).show();
                mMonthlySubscribed = true;
                ParsePush.subscribeInBackground("SignalChannel");
((MainActivity) getActivity()).loadFragment(new FragmentSubscribed());
            } else {
                Toast.makeText(getApplicationContext(), "Subscription is invalid! - server", Toast.LENGTH_SHORT).show();
                mMonthlySubscribed = false;
                ParsePush.unsubscribeInBackground("SignalChannel");
    ((MainActivity) getActivity()).loadFragment(new FragmentUnsubscribed()); 
            }
        }
        // save state 
        saveSubscriptionStateSharedPreference();

        // todo : notify the current state to the fragment

    }

为什么不从loadFragment

调用onPurchasesUpdated方法

Answer 2

我设法使用LocalBroadcastManager完成了这项工作。我将发布我的答案，目的是帮助那些正在寻找这种用例解决方案的其他人。

在我的MainActivity中，我实现了sendMessage（）方法来发送本地广播。

public static Uri GetUri(this HttpRequest request)
{
    var uriBuilder = new UriBuilder
    {
        Scheme = request.Scheme,
        Host = request.Host.Host,
        Port = request.Host.Port.GetValueOrDefault(80),
        Path = request.Path.ToString(),
        Query = request.QueryString.ToString()
    };
    return uriBuilder.Uri;
}

然后在onPurchasesUpdated（）的回调中，我正在发送上述广播消息。如下所示，

private void sendMessage() {
    Log.d("sender", "Broadcasting message subscription state update");
    Intent intent = new Intent("subscription_state");
    LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}

在每个片段中，我在下面的监听器中实现了以下给出的上述广播消息。

@Override
public void onPurchasesUpdated(List<Purchase> purchaseList) {

        for (Purchase purchase : purchaseList) {
            if (purchase.getSku().equals(SKU_MONTHLY)) {
                Log.d(TAG, "Subscription is valid! - server");
                mMonthlySubscribed = true;
            }
        }
        //// save state and notify the current state to the fragment
        saveSubscriptionStateSharedPreference();
        sendMessage();
}

当广播接收器接收到广播消息时，将触发每个片段中实现的onReceive（）。

因此，当触发onPurchasesUpdated（）回调方法时，MainActivity使用sendMessage（）发送本地广播消息。每个片段都侦听此广播消息，一旦收到消息，它就会触发loadFragment（）并导航到相应的片段。

将活动的回调状态通知为片段

2 个答案: