安卓SharedPreferences类的使用

 package com.lidaochen.phonecall;

 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.net.Uri;
 import android.os.Environment;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 import android.widget.CheckBox;
 import android.widget.EditText;
 import android.widget.TabHost;
 import android.widget.ThemedSpinnerAdapter;
 import android.widget.Toast;

 import java.util.Map;

 public class MainActivity extends AppCompatActivity{
     private EditText et_userName;
     private EditText et_pwd;
     private CheckBox cb;
     private SharedPreferences sp;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         // 初始化sp实例
         sp = getSharedPreferences("test", 0);

         // 1.获取控件
         et_userName = (EditText)findViewById(R.id.et_username);
         et_pwd = (EditText)findViewById(R.id.et_pwd);
         cb = (CheckBox)findViewById(R.id.cb);
         // 把我们需要的数据在test.xml中显示出来，然后在控件上显示出来
         String name = sp.getString("name", "");
         String pwd = sp.getString("pwd", "");
         // 将数据显示在控件上
         et_userName.setText(name);
         et_pwd.setText(pwd);
     }
     // 按钮点击事件
     public void login(View v)
     {
         // 获取userName和pwd
         String name = et_userName.getText().toString().trim();
         String pwd = et_pwd.getText().toString().trim();
         // 判断name和pwd是否为空
         if(TextUtils.isEmpty(name) || TextUtils.isEmpty(pwd))
         {
             Toast.makeText(MainActivity.this, "用户名或密码不能为空", Toast.LENGTH_LONG).show();
         }
         else
         {
             System.out.println("登录之后要干的事情！");
             if(cb.isChecked())
             {
                // 获取sp的编辑器
                 SharedPreferences.Editor edit = sp.edit();
                 edit.putString("name", name);
                 edit.putString("pwd", pwd);
                 // 把edit进行提交
                 edit.commit();
                 Toast.makeText(MainActivity.this, "保存成功！", Toast.LENGTH_LONG).show();
             }
             else
             {
                 Toast.makeText(MainActivity.this, "请勾选复选框", Toast.LENGTH_LONG).show();
             }
         }
     }
 }