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 }