我想存储一个时间值,需要检索和编辑它。我如何使用SharedPreferences来做到这一点?


当前回答

简单的方法:

保存:

getPreferences(MODE_PRIVATE).edit().putString("Name of variable",value).commit();

检索:

your_variable = getPreferences(MODE_PRIVATE).getString("Name of variable",default value);

其他回答

我想在这里补充一点,当使用SharedPreferences时,这个问题的大多数代码片段都有类似MODE_PRIVATE的东西。MODE_PRIVATE意味着无论您写入这个共享首选项的是什么,都只能由您的应用程序读取。

Whatever key you pass to getSharedPreferences() method, android creates a file with that name and stores the preference data into it. Also remember that getSharedPreferences() is supposed to be used when you intend to have multiple preference files for your application. If you intend to use single preference file and store all key-value pairs into it then use the getSharedPreference() method. Its weird why everyone (including myself) simply uses getSharedPreferences() flavor without even understanding the difference between the above two.

下面的视频教程应该会有所帮助 https://www.youtube.com/watch?v=2PcAQ1NBy98

在共享首选项中存储值:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("Name","Harneet");
editor.apply();

从共享首选项中检索值:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String name = preferences.getString("Name", "");
if(!name.equalsIgnoreCase(""))
{
    name = name + "  Sethi";  /* Edit the value here*/
}
SharedPreferences.Editor editor = getSharedPreferences("identifier", 
MODE_PRIVATE).edit();
//identifier is the unique to fetch data from your SharedPreference.


editor.putInt("keyword", 0); 
// saved value place with 0.
//use this "keyword" to fetch saved value again.
editor.commit();//important line without this line your value is not stored in preference   

// fetch the stored data using ....

SharedPreferences prefs = getSharedPreferences("identifier", MODE_PRIVATE); 
// here both identifier will same

int fetchvalue = prefs.getInt("keyword", 0);
// here keyword will same as used above.
// 0 is default value when you nothing save in preference that time fetch value is 0.

你需要在AdapterClass或任何其他类中使用SharedPreferences。 那一次只是使用这个声明和使用相同的屁股上面。

SharedPreferences.Editor editor = context.getSharedPreferences("idetifier", 
Context.MODE_PRIVATE).edit();
SharedPreferences prefs = context.getSharedPreferences("identifier", Context.MODE_PRIVATE);

//here context is your application context

用于字符串或布尔值

editor.putString("stringkeyword", "your string"); 
editor.putBoolean("booleankeyword","your boolean value");
editor.commit();

取数据与上面相同

String fetchvalue = prefs.getString("keyword", "");
Boolean fetchvalue = prefs.getBoolean("keyword", "");

为了节省

PreferenceManager.getDefaultSharedPreferences(this).edit().putString("VarName","your value").apply();

收回:

String name = PreferenceManager.getDefaultSharedPreferences(this).getString("VarName","defaultValue");

默认值为:如果该首选项不存在则返回的值。 你可以用getActivity()或getApplicationContext()来改变“this” 某些情况下

2.用于存储在共享优先级

SharedPreferences.Editor editor = 
getSharedPreferences("DeviceToken",MODE_PRIVATE).edit();
                    editor.putString("DeviceTokenkey","ABABABABABABABB12345");
editor.apply();

2.用于检索相同的用途

    SharedPreferences prefs = getSharedPreferences("DeviceToken", 
 MODE_PRIVATE);
  String deviceToken = prefs.getString("DeviceTokenkey", null);