android实现记住用户名和密码以及自动登录

package com.sdufe.login; import android.app.Activity;import android.content.Context;import android.content.Intent;import android.content.SharedPreferences;import android.content.SharedPreferences.Editor;import android.os.Bundle;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.CheckBox;import android.widget.EditText;import android.widget.Toast; /** * @author lili.guo * * 2014-6-6下午3:20:17 */public class MainActivity extends Activity {  private EditText username_et; private EditText password_et; private CheckBox rem; private CheckBox auto; private Button login; private String username,password; SharedPreferences sp;  @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);  sp=getSharedPreferences("userInfo",Context.MODE_WORLD_READABLE);  username_et=(EditText) findViewById(R.id.username); password_et=(EditText) findViewById(R.id.password); rem=(CheckBox) findViewById(R.id.remember); auto=(CheckBox) findViewById(R.id.autologin); login=(Button) findViewById(R.id.login);  if (rem.isChecked()) {  username_et.setText(sp.getString("username", "")); password_et.setText(sp.getString("password", ""));  if (auto.isChecked()) { Intent intent1=new Intent(); intent1.setClass(getApplicationContext(), Welcome.class); startActivity(intent1); }  }  login.setOnClickListener(new View.OnClickListener() {  @Override public void onClick(View v) { // TODO Auto-generated method stub username=username_et.getText().toString(); password=password_et.getText().toString();  if (username.equals("Thea")&&password.equals("123")) {    Toast.makeText(getApplicationContext(), "登录成功", Toast.LENGTH_SHORT).show();    if (rem.isChecked()) {  Editor editor=sp.edit();  editor.putString("username", username);  editor.putString("password", password);  editor.commit();  }    Intent intent2=new Intent();  intent2.setClass(getApplicationContext(), Welcome.class);  startActivity(intent2); }   } }); }  @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } }

if (rem.isChecked()) {  username_et.setText(sp.getString("username", "")); password_et.setText(sp.getString("password", ""));  if (auto.isChecked()) { Intent intent1=new Intent(); intent1.setClass(getApplicationContext(), Welcome.class); startActivity(intent1); }  }

if (rem.isChecked()) {  Editor editor=sp.edit();  editor.putString("username", username);  editor.putString("password", password);  editor.commit();  }    Intent intent2=new Intent();  intent2.setClass(getApplicationContext(), Welcome.class);  startActivity(intent2);