<RelativeLayout     xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"      >     <TextView          android:id="@+id/textview1"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignParentLeft="true"         android:layout_alignParentTop="true"         android:layout_marginTop="16dp"         android:text="用户名"/>     <EditText          android:id="@+id/eduserName"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignParentRight="true"         android:layout_alignTop="@+id/textview1"         android:layout_toRightOf="@+id/textview1"         android:ems="10"/>     <TextView         android:id="@+id/textview2"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignParentLeft="true"         android:layout_alignRight="@+id/textview1"         android:layout_below="@+id/eduserName"         android:layout_marginTop="16dp"         android:text="密码" />          <EditText              android:id="@+id/eduserPassword"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:layout_alignLeft="@+id/eduserName"              android:layout_alignParentRight="true"              android:layout_alignTop="@+id/textview2"              android:ems="10" />          <CheckBox              android:id="@+id/chkSaveName"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:layout_alignParentLeft="true"              android:layout_below="@+id/eduserPassword"              android:text="保存用户名" />          <Button              android:id="@+id/btnLogin"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:layout_alignParentLeft="true"              android:layout_below="@+id/chkSaveName"              android:text="登录" />          <Button              android:id="@+id/btnCancel"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:layout_alignBaseline="@+id/btnLogin"              android:layout_alignBottom="@+id/btnLogin"              android:layout_toRightOf="@+id/btnLogin"              android:text="取消" /></RelativeLayout>

package com.example.shared;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.CheckBox;import android.widget.EditText;import android.widget.Toast;import android.app.Activity;import android.content.SharedPreferences;import android.content.SharedPreferences.Editor;import android.os.Bundle;public class MainActivity extends Activity {        EditText eduserName,eduserPassword;    CheckBox chk;    SharedPreferences pref;    Editor editor;    Button bt1;    Button bt2;        @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        eduserName = (EditText) findViewById(R.id.eduserName);        eduserPassword = (EditText) findViewById(R.id.eduserPassword);        chk  = (CheckBox) findViewById(R.id.chkSaveName);        pref = getSharedPreferences("userInfo", MODE_PRIVATE);        editor = pref.edit();//启用编辑        String name = pref.getString("userName", "");        if (name == null) {            chk.setChecked(false);        }else {            chk.setChecked(true);            eduserName.setText(name);        }                bt1 = (Button) findViewById(R.id.btnLogin);        bt2 = (Button) findViewById(R.id.btnCancel);                bt1.setOnClickListener(new OnClickListener() {                @Override            public void onClick(View arg0) {                String name  = eduserName.getText().toString().trim();//trim去掉首尾空格                String pass  = eduserPassword.getText().toString().trim();                if("admin".equals(name)&&"123456".equals(pass)){//随便设个密码先看看                    if(chk.isChecked()){                        editor.putString("userName", name);                        editor.commit();//提交                        Toast.makeText(MainActivity.this, "登录成功", Toast.LENGTH_LONG).show();                    }else{                        editor.remove("userName");                        editor.commit();                    }                }else {                    Toast.makeText(MainActivity.this, "禁止登陆", Toast.LENGTH_LONG).show();                }            }        });            }    }