android 使用sharedPreferences保存用户设置的参数

官方文档介绍：

Using Shared Preferences

The

SharedPreferences

class provides a general framework that allows you to save
and retrieve persistent key-value pairs of primitive data types. You can use

SharedPreferences

to
save any primitive data: booleans, floats, ints, longs, and strings. This data will persist across user sessions (even if your application is killed).

User Preferences

Shared preferences are not strictly for saving "user preferences," such as what ringtone a user has chosen. If you're interested in creating user preferences for your application, see

PreferenceActivity

,
which provides an Activity framework for you to create user preferences, which will be automatically persisted (using shared preferences).

To get a

SharedPreferences

object for your application, use one of two methods:

getSharedPreferences()

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

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.

To write values:

Call

edit()

to get a

SharedPreferences.Editor

.

Add values with methods such as

putBoolean()

and

putString()

.

Commit the new values with

commit()

To read values, use

SharedPreferences

methods such as

getBoolean()

and

getString()

.

a.示例程序：保存用户设置的数据

/**
* 保存各项参数
* @param name 姓名
* @param age 年龄
*/
public void save(String name, int age) {
SharedPreferences preferences = context.getSharedPreferences("preferences", Context.MODE_PRIVATE);
Editor edit = preferences.edit();
edit.putString("name", name);
edit.putInt("age", age);
edit.commit();
}

在保存之后，sharedPreferences将会把数据保存在 /data/data/<应用程序包名>/shared_pres/目录下，且使用xml方式保存数据

示例程序保存的数据是：

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<int name="age" value="23" />
<string name="name">g形成</string>
</map>

b.示例程序：从sharedPreferences中读取数据

/**
* @return 返回参数设置数据
*/
public Map<String, String > getPreferences(){
Map<String, String> params = new HashMap<String, String>();
SharedPreferences sp = context.getSharedPreferences("preferences", Context.MODE_PRIVATE);
params.put("name", sp.getString("name", ""));
params.put("age", String.valueOf(sp.getInt("age", 0)));
return params;
}