如何使用意图来更新活动？ [英] How to use an intent to update an activity?

问题描述

我有一个下载文件的服务。当下载完成后，我想更新我的活动，但前提是活动运行。我不想让活动来启动，如果它尚未运行。

I have a service that is downloading a file. When the download is done, I would like to update my "Downloaded files" list in my Activity, but only if the Activity is running. I do not want the Activity to start if it's not already running.

我希望我可以通过一个新的做意图有一些特殊的标志。

I was hoping I could do this by making a new Intent with some special flag.

任何人有任何想法我如何能做到这一点？一个小小的code例如可能？

Anyone have any idea how I can achieve this? A tiny code example maybe?

推荐答案

您可以创建新的BroadcastReceiver实例，并做一些事情沿着你的Activity的onResume这些行（）方法：

You can create new BroadcastReceiver instance and do something along these lines on your Activity's onResume() method:

registerReceiver(myReceiver, new IntentFilter(DownloadService.ACTION_FILE_DOWNLOADED));

在此之后，覆盖myReceiver的的onReceive（）方法来调用一个函数，更新所需的组件：

After that, override myReceiver's onReceive() method to call a function that updates the component you want:

@Override 
public void onReceive(Context context, Intent intent) {
...
    updateViewWithData(service.getNewFileData());
...
}

在你活动的的onPause（）方法，只是注销接收器：

On your Activity's onPause() method, just unregister the receiver:

unregisterReceiver(myReceiver);

我希望这会帮助你，随时问，如果有什么不清楚的。

I hope that this would help you, feel free to ask if there is something unclear.

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