从不同的活动共享preferences [英] SharedPreferences from different activity

问题描述

我从活动的负载共享preferences以下列方式：

I load from activity A the SharedPreferences in following way:

private void SavePreferences(String key, String value){
    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(key, value);
    editor.commit();
}

在活动BI要加载的共享preferences。下面是一个NullPointerException异常：

At activity B I want to load the SharedPreferences. Following was a NullPointerException:

private void LoadPreferences(){   
    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
    data = sharedPreferences.getString("name", "08:00") ;
}

如果我尝试下，我得到这个编译错误：A型没有封闭实例是在范围访问

If I try following, I get this compilation error: "No enclosing instance of the type A is accessible in scope"

private void LoadPreferences(){   
    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(A.this);
    data = sharedPreferences.getString("name", "08:00") ;
}

我怎样才能访问这些数据？

How can I access the data?

推荐答案

使用 getApplicationContext（）而不是这在这两个行业为：

use getApplicationContext() instead of this in both Activities as:

在活性的共享preferences以下列方式：

In activity A the SharedPreferences in following way:

 private void SavePreferences(String key, String value){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());

        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
        Intent sd=new Intent(this,Secongtess.class);
        startActivity(sd);
       }

而在b活动获得价值为：

and in Activity B get Value as:

 private void LoadPreferences(){   
       SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
     String  data = sharedPreferences.getString("name", "08:00") ;
     Toast.makeText(this,data, Toast.LENGTH_LONG).show();
   }

因为作为医生说：

because as doc says:

<一个href="http://developer.android.com/reference/android/$p$pference/$p$pferenceManager.html#getDefaultShared$p$pferences%28android.content.Context%29">getDefaultShared$p$pferences(Context上下文）：

获取一个共享preferences实例指向缺省文件   在给定的上下文中使用的由preference框架

Gets a SharedPreferences instance that points to the default file that is used by the preference framework in the given context.

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