android >SharedPreferences 数据存储

 

package sp.mft;

import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;

public class SpActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        
        // xml 目录在 /data/data/PACKAGE_NAME /shared_prefs
        
        ///////////////////// 存储
                
        String PREFS_NAME = "ipsensor_contrl";       
        
        SharedPreferences sp = getSharedPreferences(PREFS_NAME, 0);        
        SharedPreferences.Editor editor = sp.edit();
        
        editor.putString("username", "asdfasd");
        editor.putString("password", "asdfasdf");
        
        editor.commit();


		///////////////////删除
		String PREFS_NAME = "ipsensor_contrl";       
        
        SharedPreferences sp = getSharedPreferences(PREFS_NAME, 0);        
        SharedPreferences.Editor editor = sp.edit();
		
		editor.remove("username");  
		editor.remove("password");   
		editor.commit();
        
        
        //////////////////// 读取
        SharedPreferences getsp = getSharedPreferences(PREFS_NAME, 0);
        String name = getsp.getString("username", "");
        System.out.println(name);
        
        
        
        
        
    }
}

  

 

 

 

 

 

如果是重复插入 则 会 替换掉 原来的 

/data/data/PACKAGE_NAME /shared_prefs/ ipsensor_contrl.xml

 

 

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
<string name="password">asdfasd</string>
<string name="username">asdfasdf</string>
</map>

 

 

判断值是否存在

String data = settings.getString("nick", null);
如果记录不存在，data的值，就为后面方法的第二个参数，你写的null，就是判断data==null了