Android的SharedPreferences实用技巧

转自：http://blog.csdn.net/jingfeizhu/article/details/10017779

SharedPreferences也是一种轻型的数据存储方式，它的本质是基于XML文件存储key-value键值对数据，通常用来存储一些简单的配置信息。其存储位置在/data/data/<包名>/shared_prefs目录下。SharedPreferences对象本身只能获取数据而不支持存储和修改，存储修改是通过Editor对象实现。实现SharedPreferences存储的步骤如下：
一、根据Context获取SharedPreferences对象
二、利用edit()方法获取Editor对象。
三、通过Editor对象存储key-value键值对数据。
四、通过commit()方法提交数据。

 1 public class MainActivity extends Activity {
 2     @Override
 3     public void onCreate(Bundle savedInstanceState) {
 4        super.onCreate(savedInstanceState);
 5        setContentView(R.layout.main);
 6        
 7        //获取SharedPreferences对象
 8        Context ctx = MainActivity.this;       
 9        SharedPreferences sp = ctx.getSharedPreferences("pref", MODE_PRIVATE);
10        //存入数据
11        Editor editor = sp.edit();
12        editor.putString("name", "jeff");
13        editor.putInt("score", 0);
14        editor.putBoolean("playagain", true);
15        editor.commit();
16        
17     }
18 }

上面的例子使用起来比较麻烦，这里给出一种简单的封装方案：

 1 import java.util.Map.Entry;
 2 
 3 
 4 import android.content.ContentValues;
 5 import android.content.Context;
 6 import android.content.SharedPreferences;
 7 
 8 
 9 public class MyPreference {
10 
11     private static final String PREFERENCE_NAME = "my.db";
12 
13     private SharedPreferences mPreference;
14 
15     public MyPreference(Context ctx) {
16         mPreference = ctx.getApplicationContext().getSharedPreferences(PREFERENCE_NAME, Context.MODE_PRIVATE);
17     }
18 
19 
20     public boolean putStringAndCommit(String key, String value) {
21         return mPreference.edit().putString(key, value).commit();
22     }
23 
24 
25     public boolean putIntAndCommit(String key, int value) {
26         return mPreference.edit().putInt(key, value).commit();
27     }
28 
29     public boolean putBooleanAndCommit(String key, boolean value) {
30         return mPreference.edit().putBoolean(key, value).commit();
31     }
32 
33     public boolean putIntAndCommit(ContentValues values) {
34         SharedPreferences.Editor editor = mPreference.edit();
35         for (Entry<String, Object> value : values.valueSet()) {
36             editor.putString(value.getKey(), value.getValue().toString());
37         }
38         return editor.commit();
39     }
40 
41 
42     public String getString(String key) {
43         return getString(key, "");
44     }
45 
46     public String getString(String key, String defValue) {
47         return mPreference.getString(key, defValue);
48     }
49 
50     public int getInt(String key) {
51         return getInt(key, -1);
52     }
53 
54 
55     public int getInt(String key, int defValue) {
56         return mPreference.getInt(key, defValue);
57     }
58 
59     public boolean getBoolean(String key) {
60         return getBoolean(key, false);
61     }
62 
63     public boolean getBoolean(String key, boolean defValue) {
64         return mPreference.getBoolean(key, defValue);
65     }
66 }

使用方式如下：

 1 public class MainActivity extends Activity {
 2     @Override
 3     public void onCreate(Bundle savedInstanceState) {
 4        super.onCreate(savedInstanceState);
 5        setContentView(R.layout.main);
 6        
 7        MyPreference pref = new MyPreference(this);
 8        pref.putStringAndCommit("name", "jeff");
 9        
10     }
11 }

Android的SharedPreferences实用技巧

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