sharedPreferences

package tjuci.edu.dl;

import android.app.Activity;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class sharePreferences extends Activity {
EditText userName, userCode;
CheckBox chk;
SharedPreferences prefer;

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
userName = (EditText) findViewById(R.id.userName);
userCode = (EditText) findViewById(R.id.userCode);
chk = (CheckBox) findViewById(R.id.checkBox);
prefer = getSharedPreferences("userInfo", MODE_PRIVATE);
// System.out.println("========="+"pref是否为null"+pref==null);

System.out.println("1111111111111");
boolean b = prefer == null;
// System.out.println("prefer是否为null"+b);
String xm = prefer.getString("xingming", "");
String mm = prefer.getString("mima", "");
userName.setText(xm);
userCode.setText(mm);

if(xm.equals("")){
chk.setChecked(false);
System.out.println("88888,xm:"+xm);
}else{
System.out.println("999999,xm:"+xm);
chk.setChecked(true);
}
}
public void doClick(View v) {
switch (v.getId()) {
case R.id.btnLogin:
String user = userName.getText().toString().trim();
String code = userCode.getText().toString().trim();
if (user.equals("wyl") && code.equals("123")) {
if (chk.isChecked()) {

Editor edit = prefer.edit();
edit.putString("xingming", user);
edit.putString("mima", "123");
edit.commit();
System.out.println("===========");
}else{
chk.setChecked(false);
}
System.out.println("dddddd");
Toast.makeText(this, "登陆成功！", 100).show();
}else{
Editor e = prefer.edit();
e.remove("xingming");
e.remove("mima");
e.commit();
Toast.makeText(this, "登陆失败，请确认！", 100).show();
String Xm = prefer.getString("xingming", "----");
Toast.makeText(this, "姓名："+Xm, 100).show();
}
break;
default:
break;
}
}

}