为什么要使用Context.MODE_PRIVATE或Context.MODE_WRITABLE? [英] Why use Context.MODE_PRIVATE or Context.MODE_WRITABLE?

问题描述

我对context.MODE_PRIVATE或MODE_READABLE, WRITABLE的理解是，这些函数为共享首选项创建文件.

What I understood about context.MODE_PRIVATE or MODE_READABLE, WRITABLE is that those functions make files for sharedprefrences.

我想知道context.getSharedPreferences(KEY, Context.MODE_PRIVATE)和getSharedPreferences(KEY, 0);之间有什么区别.

I am wondering what the difference is between context.getSharedPreferences(KEY, Context.MODE_PRIVATE) and getSharedPreferences(KEY, 0);.

getSharedPreferences从xml文件夹中检索其首选项.并且Context.MODE_PRIVATE存储其文件.以及为什么同时使用context.getSharedPreferences(KEY, Context.MODE_PRIVATE)和context.getSharedPreferences(KEY, Context.MODE_PRIVATE)创建文件的原因，使用context.getSharedPreferences(KEY, Context.MODE_PRIVATE).

getSharedPreferences retrieves its preferences from a xml folder as far as I know. And Context.MODE_PRIVATE stores its files. And why use context.getSharedPreferences(KEY, Context.MODE_PRIVATE) if both getSharedPreferences(KEY, 0) and context.getSharedPreferences(KEY, Context.MODE_PRIVATE) makes files.

下面是我注意到Context.MODE_PRIVATE的Facebook API的一部分.

Below is part of the Facebook API where I noticed Context.MODE_PRIVATE.

public static boolean save(Facebook session, Context context) {
    Editor editor =
        context.getSharedPreferences(KEY, Context.MODE_PRIVATE).edit();
    editor.putString(TOKEN, session.getAccessToken());
    editor.putLong(EXPIRES, session.getAccessExpires());
    return editor.commit();
}
public static boolean restore(Facebook session, Context context) {
    SharedPreferences savedSession =
        context.getSharedPreferences(KEY, Context.MODE_PRIVATE);
    session.setAccessToken(savedSession.getString(TOKEN, null));
    session.setAccessExpires(savedSession.getLong(EXPIRES, 0));
    return session.isSessionValid();
}

推荐答案

根据

There is no Context.MODE_WRITABLE or Context.MODE_READABLE according to the javadoc. So I assume that you are talking about Context.MODE_WORLD_WRITABLE or Context.MODE_WORLD_READABLE. (Not that this is actually relevant to your question ...)

我想知道两者之间有什么区别

I am wondering what is the difference between

    context.getSharedPreferences(KEY, Context.MODE_PRIVATE)

和

    context.getSharedPreferences(KEY, 0);

没有功能上的区别. Context.MODE_PRIVATE是值为零的int常量；有关详细信息，请参考上面链接的javadoc.尽管前者更具可读性，但从代码风格的角度来看，它更可取.

There is no functional difference. Context.MODE_PRIVATE is an int constant with value zero; refer to the javadoc linked above for the details. The former is more readable though, and that makes it preferable from a code style perspective.

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