Xamarin Android:从另一个应用程序获取一个应用程序的状态信息

问题描述

我有两个Xamarin Android应用程序-我们称它们为"Archy"和"Mehitabel".

I have two Xamarin Android apps -- let's call them "Archy" and "Mehitabel".

Archy具有一些持久状态信息(为了便于说明，它位于SQLite DB中).

Archy has some persistent state information (which, let's say for the sake of argument, is in a SQLite DB).

如果Mehitabel发生某件事，她需要知道一些状态信息.

If a certain thing happens to Mehitabel, she needs to know a piece of that state information.

为了完成这一壮举，我让Mehitabel向Archy发送了一份意向书.阿奇有一个广播接收器，可以听到它，收集必要的状态，然后向梅希塔贝尔发出不同的意图.

To accomplish this feat, I have Mehitabel send an intent to Archy. Archy has a broadcast receiver that hears it, gathers the necessary state, and fires a different intent back to Mehitabel.

这是来自Archy的代码:

Here's the code from Archy:

[BroadcastReceiver(Enabled = true)]
[IntentFilter(new [] { "com.example.Archy.SendStateToMehitabel"})]
public class StateQueryReceiver : BroadcastReceiver
{
    public override void OnReceive(Context context, Intent intent)
    {
        var msg = new Intent("com.example.Mehitabel.StateFromArchy");
        msg.PutExtra("ImportantStateInfo", GetSomeState());
        context.SendBroadcast(msg);
    }
}

这是Mehitabel的代码:

And here's the code from Mehitabel:

    private async Task AskArchyForState()
    {
        var filter = new IntentFilter("com.example.Mehitabel.StateFromArchy");
        var csrc = new TaskCompletionSource<bool>();
        var rcvr = new ActionBroadcastReceiver((context, intent) =>
        {
            State = intent.GetStringExtra("ImportantStateInfo");
            csrc.TrySetResult(State != null);
        });
        RegisterReceiver(rcvr, filter);

        var msg = new Intent("com.example.Archy.SendStateToMehitabel");
        SendBroadcast(msg);

        var task = await Task.WhenAny(csrc.Task, Task.Delay(Timeout));

        UnregisterReceiver(rcvr);
        if (task != csrc.Task)
            bomb("Archy has not answered state query after {0}ms", Timeout);
        if (!csrc.Task.IsCompletedSuccessfully || csrc.Task.Result == false)
            bomb("failed to get all necessary state from Archy");
    }

如果Archy实际上正在运行(即显示在最近"列表中)，那么一切都很好.如果Archy没有运行，则Archy的接收者代码将永远不会执行，而Mehitabel也会超时.

That all works great, provided Archy is actually running (i.e., shown in the "recent" list). If Archy isn't running, Archy's receiver code is never executed and Mehitabel times out.

我希望我缺少一些简单的东西(例如，接收者属性之一中的标志，或者com.example.Archy.SendStateToMehitabel意向中的一些秘密调味品.)

My hope is I'm missing something simple (like a flag in one of the receiver attributes, or some secret sauce in the com.example.Archy.SendStateToMehitabel intent).

你能告诉我我在这里想念什么吗?

Can you tell me what I'm missing here?

我是否需要使用一种完全不同的方法(例如在Archy中进行Mehitabel StartActivityForResult()活动，或使用在启动时一直运行并一直运行的服务)?

Do I need to be using a completely different approach (like having Mehitabel StartActivityForResult() an activity within Archy, or using a service that starts on boot and runs all the time)?

推荐答案

根据我的研究，我认为您可以在需要Mehitabel中的数据之前打开Archy.这是有关使用代码打开应用程序的演示.

Based on my research, I think you could open Archy before you need the data in Mehitabel. This is demo about opening an app in code.

 Intent launchIntent = PackageManager.GetLaunchIntentForPackage("NewTestApp.NewTestApp");
            if (launchIntent != null)
            {
                StartActivity(launchIntent);

            }

注意:NewTestApp.NewTestApp是Archy的程序包名称.

Note:NewTestApp.NewTestApp is package name of Archy.

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