在Android中获取Application实例的正确方法 [英] Correct way to get the instance of Application in android

问题描述

以下哪种方式更适合获取Application实例

Which of these ways is more proper for getting the instance of Application

1. 初始化Application.onCreate()中的静态字段并提供对其的静态访问

1. Initialise static field in Application.onCreate() and provide static access to it

public class MyApplication extends Application {

    private static MyApplication sInstance;

    @Override
    public void onCreate() {
        super.onCreate();
        sInstance = this;
    }

    public static MyApplication getInstance() {
        return MyApplication.sInstance;
    }
}

public class MyBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        MyApplication application = MyApplication.getInstance();
    }
}

创建将Context作为参数的静态方法，并将该上下文转换为MyApplication

Create static method which takes Context as param and cast that Context to MyApplication

public class MyApplication extends Application {

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

    public static MyApplication getInstance(Context context) {
        return ((MyApplication) context.getApplicationContext());
    }
}

public class MyBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        MyApplication application = MyApplication.getInstance(context);
    }
} 

推荐答案

如果您仅需要应用程序的实例，我将推荐方法3.

I would recommend method 3 if you only need the instance of the Application.

如果您的Application类中还有其他方法，我建议使用方法1，因为您可以更清楚地进行

I would recommend method 1 if you had additional methods in your Application class because you can more clearly do

MyApplication.getInstance().foo();

方法2只是方法3的快捷方式，因此我不推荐使用.

Method 2 is just a shortcut for method 3, so I wouldn't recommend it.

总而言之，这是优先选择的问题.没有一种正确"的方法，因为它们都能正常工作.

All in all, it's a matter of preference. There is no one "correct" way because they'll all work.

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