Android SharedPreferences一般的读写 的用法。

Android SharedPreferences一般用于轻量级的数据存储，比如用户名和密码等。

 package com.lixu.testsharepreferences;

 import android.app.Activity;
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.Editor;
 import android.os.Bundle;
 import android.widget.Toast;

 public class MainActivity extends Activity {

     private static final String USER_NAME = "username";
     private static final String USER_PWS = "userpws";
     private String NAME = "name";

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         writeSharedPreferences();
         readSharedPreferences();

     }

     // Context.MODE_PRIVATE 这个是设置访问权限 意思是只有本app可以读写里面的数据
     // 如果SharedPreferences里面没有写入数据 就返回"无值"；
     private void readSharedPreferences() {
         SharedPreferences sp = this.getSharedPreferences(NAME, Context.MODE_PRIVATE);

         String str1 = sp.getString(USER_NAME, "无值");
         String str2 = sp.getString(USER_PWS, "无值");

         Toast.makeText(getApplicationContext(), "用户名是：" + str1, 1).show();

         Toast.makeText(getApplicationContext(), "用户密码是：" + str2, 1).show();

     }

     private void writeSharedPreferences() {
         SharedPreferences sp = this.getSharedPreferences(NAME, Context.MODE_PRIVATE);

         Editor edt = sp.edit();
         edt.putString(USER_NAME, "lixu");
         edt.putString(USER_PWS, "123456789");
         // 提交
         edt.commit();

     }

 }

运行效果：