到处使用应用程序上下文? [英] Using Application context everywhere?

问题描述

在 Android 应用中，以下方法是否有问题:

In an Android app, is there anything wrong with the following approach:

public class MyApp extends android.app.Application {

    private static MyApp instance;

    public MyApp() {
        instance = this;
    }

    public static Context getContext() {
        return instance;
    }

}

并在需要上下文的任何地方(例如 SQLiteOpenHelper)传递它(当然不会泄漏)?

and pass it everywhere (e.g. SQLiteOpenHelper) where context is required (and not leaking of course)?

推荐答案

这种方法有几个潜在的问题，但在很多情况下(比如你的例子)它会很好地工作.

There are a couple of potential problems with this approach, though in a lot of circumstances (such as your example) it will work well.

特别是在处理任何需要 Context 的 GUI 时，你应该小心.例如，如果您将应用程序上下文传递到 LayoutInflater 中，您将得到一个异常.一般来说，您的方法非常好:在该 Activity 中使用 Activity's Context 是一种很好的做法 和 Application Context 将超出 Activity 范围的上下文传递给 避免内存泄漏.

In particular you should be careful when dealing with anything that deals with the GUI that requires a Context. For example, if you pass the application Context into the LayoutInflater you will get an Exception. Generally speaking, your approach is excellent: it's good practice to use an Activity's Context within that Activity, and the Application Context when passing a context beyond the scope of an Activity to avoid memory leaks.

此外，作为您的模式的替代，您可以使用在 Context 上调用 getApplicationContext() 的快捷方式strong> 对象(例如 Activity)以获取应用程序上下文.

Also, as an alternative to your pattern you can use the shortcut of calling getApplicationContext() on a Context object (such as an Activity) to get the Application Context.

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