最好的办法，从服务交付导致Android的结合 [英] The best way to deliver result from Service binding in Android

问题描述

如何从服务结果，如果任务异步运行？

How to get result from the Service, if task run asynchronously?

如果一个任务被同步于主线程开始，不存在问题：

If a task is started synchronously in main thread, there is no problem:

Object result = serviceInstanceInActivity.callMethod();

但是，如果任务在其他线程中运行，我们有一个问题：

But if the task runs in other thread, we have a problem:

void asyncMethodInService() {
    new MyTask().execute();
}

class MyTask extends AsyncTask<Void, Void, Result> {
    // implementation of the others methods

    public void onPostExecute(Result result) {
        // We need to send data to Activity here
    }
}

当然，它是通过ServiceConnection工作。在平时上课，我会用接口回调，但如果我同样在这里做，活动实例将通过回调服务泄露。

Of Course, it's work via ServiceConnection. In usual class, I would use interfaces as callback, but if I do same here, the Activity instance will leaked in Service via callback.

那么，什么是推荐的方式在这个情况下，提供数据？

So, what is recommended way to deliver data in this cases?

推荐答案

我会用的 LocalBroadcastManager 播出的意图包含结果，让任何有兴趣的活动，可以注册并在服务完成其任务接收广播。

I would use LocalBroadcastManager to broadcast an Intent containing the result, so that any interested activities can register for and receive the broadcast when the service completes its task.

如果该数据是复杂的，是不实际的打包成一个意图，你需要得到一点创意。你应该使用的ContentProvider ，并把内容URI到意向该活动就可以用它来查询结果。或者您可能能够将结果存储在一个静态单（或在您的应用程序实例），只是有活动时，它接收广播检索更新后的值。这取决于你的需求。

If the data is complex and is not practical to pack into an Intent, you need to get a bit creative. You should probably use a ContentProvider and put a content URI into the intent which the activities can then use to query for the result. Or you might be able to store the result on a static singleton (or on your application instance) and just have the activity retrieve the updated value when it receives the broadcast. It depends on your requirements.

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