Android-在单独的类中使用共享首选项? [英] Android - Using Shared Preferences in separate class?

问题描述

我想使用Android中的共享首选项"保存数据.但是我希望使用单独的类来完成此任务.我已经像下面这样实现了该类，

I want to save data using Shared Preferences in android. But I am looking to use separate class to do this task. I have implemented that class like below,

import android.content.Context;
import android.content.SharedPreferences;

public class SavePref {

    private Context context;

    public SavePref(Context context){
        this.context = context;
    }

    public void saveInt(String key, int value) {

        SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPref.edit();
        editor.putInt(key, value);
        editor.commit();

    }

}

但是getActivity()上有错误

The method getActivity() is undefined for the type SavePref

如何解决这个问题?
谢谢

How to solve this?
Thanks

推荐答案

getActivity()是Fragment的方法，而不是您的SavePref的方法.在您的情况下，简单的解决方法是使用作为成员变量保留的上下文来检索SharedPreferences.方法的另一种选择是避免将上下文保留为成员变量，以某种方式将共享的首选项链接到您的SavePref类的实例，并使用静态方法

getActivity() is a method of Fragment not of your SavePref. In your case the simple fix is to use the Context you are keeping as member variable to retrieve the SharedPreferences. An alternative to your approach is to avoid keeping the context as member variable, linking somehow the shared preferences to an instance of of your SavePref class, and have a static method

  public static void saveInt(Context context, String key, int value) {
        SharedPreferences sharedPref = context.getDefaultSharedPreferences(Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPref.edit();
        editor.putInt(key, value);
        editor.commit();
    }

并解决以下方法:

SavePref.saveInt(getActivity(), key, value);

来自Fragment或

SavePref.saveInt(this, key, value);

中的

.这样，您不需要每次调用saveInt时都实例化SavePref，并且可以避免存储对Context的引用.

from an Activity. This way you don't need to instantiate SavePref every time you need to call saveInt, and you can avoid to store a reference to the Context.

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