Android：利用SharedPreferences实现自动登录

public class LoginActivity extends Activity { private EditText username; private EditText userpassword; private CheckBox remember; private CheckBox autologin; private Button login; private SharedPreferences sp; private String userNameValue,passwordValue;  @Override protected void onCreate(Bundle savedInstanceState) {  // TODO Auto-generated method stub  super.onCreate(savedInstanceState);  setContentView(R.layout.login);    // 初始化用户名、密码、记住密码、自动登录、登录按钮  username = (EditText) findViewById(R.id.username);  userpassword = (EditText) findViewById(R.id.userpassword);  remember = (CheckBox) findViewById(R.id.remember);  autologin = (CheckBox) findViewById(R.id.autologin);  login = (Button) findViewById(R.id.login);  sp = getSharedPreferences("userInfo", 0);  String name=sp.getString("USER_NAME", "");  String pass =sp.getString("PASSWORD", "");    boolean choseRemember =sp.getBoolean("remember", false);  boolean choseAutoLogin =sp.getBoolean("autologin", false); //  Toast.makeText(this, name, Toast.LENGTH_SHORT).show();    //如果上次选了记住密码，那进入登录页面也自动勾选记住密码，并填上用户名和密码  if(choseRemember){   username.setText(name);   userpassword.setText(pass);   remember.setChecked(true);  }  //如果上次登录选了自动登录，那进入登录页面也自动勾选自动登录  if(choseAutoLogin){   autologin.setChecked(true);  }        login.setOnClickListener(new OnClickListener() {     // 默认可登录帐号tinyphp,密码123   @Override   public void onClick(View arg0) {    userNameValue = username.getText().toString();    passwordValue = userpassword.getText().toString();    SharedPreferences.Editor editor =sp.edit();        // TODO Auto-generated method stub    if (userNameValue.equals("tinyphp")      && passwordValue.equals("123")) {     Toast.makeText(LoginActivity.this, "登录成功",       Toast.LENGTH_SHORT).show();          //保存用户名和密码     editor.putString("USER_NAME", userNameValue);     editor.putString("PASSWORD", passwordValue);          //是否记住密码     if(remember.isChecked()){            editor.putBoolean("remember", true);           }else{      editor.putBoolean("remember", false);         }                         //是否自动登录      if(autologin.isChecked()){              editor.putBoolean("autologin", true);             }else{       editor.putBoolean("autologin", false);      }     editor.commit();           //跳转     Intent intent =new Intent(LoginActivity.this,SuccessActivity.class);     startActivity(intent);    } else {     Toast.makeText(LoginActivity.this, "用户名或密码错误，请重新登录!",       Toast.LENGTH_SHORT).show();    }   }  }); }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:padding="10dp" > <TextView  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text="用户名：" /> <EditText  android:id="@+id/username"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:ems="10"  android:inputType="textPersonName" > </EditText> <TextView  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:layout_marginTop="10dp"  android:text="密码：" /> <EditText  android:id="@+id/userpassword"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:ems="10"  android:inputType="textPassword" > </EditText> <CheckBox  android:id="@+id/remember"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text="记住密码" /> <CheckBox  android:id="@+id/autologin"  android:layout_width="wrap_content"  android:layout_height="wrap_content"  android:text="自动登录" /> <Button  android:id="@+id/login"  android:layout_width="match_parent"  android:layout_height="wrap_content"  android:text="登录" /></LinearLayout>