Android轻量存储值SharedPreference存世实例

package com.example.sharedpreference1;

import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.provider.Settings;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
EditText etUserName,etUserPass;
CheckBox chk;
Button btnLogin,btnCancel;
TextView name,pass;
SharedPreferences pref;
SharedPreferences.Editor editor;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
etUserName = (EditText) findViewById(R.id.etuserName);
etUserPass = (EditText) findViewById(R.id.etPass);
btnLogin = (Button) findViewById(R.id.btnLogin);
btnCancel = (Button) findViewById(R.id.btnCnancel);
chk = (CheckBox) findViewById(R.id.chkSaveName);

pref = getSharedPreferences("UserInfo",MODE_PRIVATE);
editor = pref.edit();

String name = pref.getString("userName","");
if (name==null)
{
chk.setChecked(false);
}
else {
chk.setChecked(true);
etUserName.setText(name);
}

}
public void doClick(View v){
switch (v.getId()){

case R.id.btnLogin:
String name = etUserName.getText().toString().trim();
String pass = etUserPass.getText().toString().trim();

if("admin".equals(name)&&"123456".equals(pass))
{
if(chk.isChecked())
{
editor.putString("userName",name);
editor.commit();

} else {
editor.remove("userName");
editor.commit();
}
Toast.makeText(MainActivity.this,"登陆成功",Toast.LENGTH_LONG).show();

}
else {
Toast.makeText(MainActivity.this,"禁止登陆",Toast.LENGTH_LONG).show();
}
break;
case R.id.btnCnancel:
break;
}

}
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.sharedpreference1.MainActivity">

<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="用户名"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<EditText
android:id="@+id/etuserName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/textView1"
android:ems="10"
android:layout_toRightOf="@+id/textView1"
android:layout_toEndOf="@+id/textView1" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="密码"
android:layout_below="@+id/etuserName"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<EditText
android:id="@+id/etPass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:layout_below="@+id/textView2"
android:layout_alignLeft="@+id/etuserName"
android:layout_alignStart="@+id/etuserName"
android:layout_alignRight="@+id/etuserName"
android:layout_alignEnd="@+id/etuserName" />

<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="保存用户名"
android:id="@+id/chkSaveName"
android:layout_below="@+id/etPass"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="登录"
android:id="@+id/btnLogin"
android:layout_below="@+id/chkSaveName"
android:layout_alignRight="@+id/chkSaveName"
android:onClick="doClick"
android:layout_alignEnd="@+id/chkSaveName" />

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="取消"
android:onClick="doClick"
android:id="@+id/btnCnancel"
android:layout_alignBottom="@+id/btnLogin"
android:layout_toRightOf="@+id/btnLogin"
android:layout_toEndOf="@+id/btnLogin" />
</RelativeLayout>