getDefaultSharedPreferences()和getPreferences()有什么区别? [英] What's the difference between getDefaultSharedPreferences() and getPreferences()?

问题描述

我目前正在参加开发Android应用" Udacity课程.在第3课:新活动和意图>使用SharedPreferences"部分中，讲师要求我在Android Developer网站上进行深入了解，以了解如何从SharedPreferences获取用户首选项.但是，我发现官方文档和本课程的解决方案有所不同.

I'm currently taking the "Developing Android Apps" Udacity course. In the "Lesson 3: New Activities and Intents > Use SharedPreferences" segment, the instructor asked me to dig around the Android Developer site for how to get the user preferences from SharedPreferences. However, I found it different between the official documentation and the course's solution.

Udacity课程的解决方案说，为PreferenceActivity，您应该致电:

The Udacity course's solution says, to grab a SharedPreferences instance for the PreferenceActivity, you should call:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());

(其中getActivity()在这里只是Context，因为它在Fragment内部被调用.)

(where getActivity() is simply the Context here because it's called inside a Fragment.)

在Android开发者网站上官方文档表示您应该致电:

While the official documentation on Android Developer Site indicates that you should call:

SharedPreferences prefs = getActivity().getPreferences(Context.MODE_PRIVATE)

那么PreferenceManager.getDefaultSharedPreferences(Context context)和Activity.getPreferences(int mode)有什么区别?

请注意::该问题不涉及有关getSharedPreferences()的任何内容，该文件需要文件名.这与getPreferences()和getDefaultSharedPreferences()之间的区别有关.

Please note: This question does not involve anything about getSharedPreferences() which requires a file name. It's about the difference between getPreferences() and getDefaultSharedPreferences().

谢谢.

推荐答案

根据您提供给Android文档的链接

Acoording to the link you provided to Android documentation

getSharedPreferences()-如果您需要多个用名称标识的首选项文件，请使用第一个参数指定该文件.

getSharedPreferences() - Use this if you need multiple preferences files identified by name, which you specify with the first parameter.

getPreferences()-如果您的活动仅需要一个首选项文件，请使用此选项.因为这将是活动"的唯一首选项文件，所以您无需提供名称.

getPreferences() - Use this if you need only one preferences file for your Activity. Because this will be the only preferences file for your Activity, you don't supply a name.

就是这样，当要保存/检索的数据可以从应用程序中的不同活动中使用时，请使用getSharedPreferences.如果这些首选项仅在一个Activity中使用，则可以使用getPreferences.

So it is, use getSharedPreferences when the data you want to save/retrieve can be used from different activities in the app. If those preferences will only be used in one Activity, you can use getPreferences.

还请注意，正如帖子中所说，链接的"getDefaultSharedPreferences将使用默认名称，例如" com.example.something_preferences"，但getSharedPreferences将需要一个名称"

also note that as said in the post you linked 'getDefaultSharedPreferences will use a default name like "com.example.something_preferences", but getSharedPreferences will require a name'

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