android从服务开始活动

android start activity from service

提问by d-man

Android:

安卓：

public class LocationService extends Service {

@Override
    public void onStart(Intent intent, int startId) {
        super.onStart(intent, startId);
        startActivity(new Intent(this, activity.class));
    }
}

I launched this service from Activity

我从 Activity

In Activityif condition satisfies start

在Activityif 条件满足开始

startService(new Intent(WozzonActivity.this, LocationService.class));

from my LocationServicementioned above could not launch Activity, how can I get context of current running Activityin service class?

从我LocationService上面提到的无法启动Activity，如何获取当前Activity在服务类中运行的上下文？

回答by d-man

From inside the Service class:

从服务类内部：

Intent dialogIntent = new Intent(this, MyActivity.class);
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(dialogIntent);

回答by Andy

I had the same problem, and want to let you know that none of the above worked for me. What worked for me was:

我遇到了同样的问题，想让您知道上述方法都不适合我。对我有用的是：

 Intent dialogIntent = new Intent(this, myActivity.class);
 dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
 this.startActivity(dialogIntent);

and in one my subclasses, stored in a separate file I had to:

在一个我的子类中，存储在一个单独的文件中，我必须：

public static Service myService;

myService = this;

new SubService(myService);

Intent dialogIntent = new Intent(myService, myActivity.class);
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
myService.startActivity(dialogIntent);

All the other answers gave me a nullpointerexception.

所有其他答案都给了我一个nullpointerexception.

回答by kellogs

Another thing worth mentioning: while the answer above works just fine when our task is in the background, the only way I could make it work if our task (made of service + some activities) was in the foreground (i.e. one of our activities visible to user) was like this:

另一件值得一提的事情：虽然当我们的任务在后台时上面的答案工作得很好，但如果我们的任务（由服务 + 一些活动组成）在前台（即我们的一个活动可见），我可以让它工作的唯一方法用户）是这样的：

    Intent intent = new Intent(storedActivity, MyActivity.class);
    intent.setAction(Intent.ACTION_VIEW);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
    storedActivity.startActivity(intent);

I do not know whether ACTION_VIEW or FLAG_ACTIVITY_NEW_TASK are of any actual use here. The key to succeeding was

我不知道 ACTION_VIEW 或 FLAG_ACTIVITY_NEW_TASK 在这里是否有任何实际用途。成功的关键是

storedActivity.startActivity(intent);

and of course FLAG_ACTIVITY_REORDER_TO_FRONT for not instantiating the activity again. Best of luck!

当然还有 FLAG_ACTIVITY_REORDER_TO_FRONT 用于不再实例化活动。祝你好运！

回答by Martin Zeitler

one cannot use the Contextof the Service; was able to get the (package) Contextalike:

一个不能使用Context的Service；能够获得（包）Context类似的：

Intent intent = new Intent(getApplicationContext(), SomeActivity.class);

回答by james

Alternately,

交替，

You can use your own Application class and call from wherever you needs (especially non-activities).

您可以使用自己的 Application 类并从您需要的任何地方（尤其是非活动）调用。

public class App extends Application {

    protected static Context context = null;

    @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();
    }

    public static Context getContext() {
        return context;
    }

}

And register your Application class :

并注册您的应用程序类：

<application android:name="yourpackage.App" ...

Then call :

然后调用：

App.getContext();

回答by GMG

If you need to recal an Activity that is in bacgrounde, from your service, I suggest the following link. Intent.FLAG_ACTIVITY_NEW_TASK is not the solution.

如果您需要从您的服务中重新调用 bacgrounde 中的 Activity，我建议使用以下链接。Intent.FLAG_ACTIVITY_NEW_TASK 不是解决方案。

https://stackoverflow.com/a/8759867/1127429

https://stackoverflow.com/a/8759867/1127429