这里我们采用写固定的账户名为：admin , 密码为12345.真正的代码肯定不能够写固定的。切记！

界面如下：

以下为Layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#ffffff"
    tools:context=".MainActivity">

   <EditText
       android:id="@+id/edt_account"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:textColor="#000000"
       android:textSize="20dp"
       android:layout_marginTop="10dp"
       android:textColorHint="#707070"
       android:hint="账户名.."/>
    <EditText
        android:id="@+id/edt_password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="#000000"
        android:layout_marginTop="10dp"
        android:textSize="20dp"
        android:textColorHint="#707070"
        android:hint="密码.."/>
    <LinearLayout
        android:layout_marginTop="10dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <CheckBox
            android:id="@+id/remember_pass"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="记住密码"
            android:textColor="#000000"
            android:layout_marginLeft="10dp"
            android:textSize="20dp"/>
    </LinearLayout>
    <Button
        android:id="@+id/login"
        android:layout_marginTop="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Login"
        android:textSize="20dp"
        android:textAllCaps="false"/>

</LinearLayout>

接着我们来写主代码：

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private EditText edt_account,edt_password;
    private CheckBox rememberPassword;
    private Button login;
    private SharedPreferences pref;
    private SharedPreferences.Editor editor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        pref = PreferenceManager.getDefaultSharedPreferences(this);
        edt_account = (EditText)findViewById(R.id.edt_account);
        edt_password = (EditText)findViewById(R.id.edt_password);
        rememberPassword = (CheckBox)findViewById(R.id.remember_pass);
        login = (Button)findViewById(R.id.login);
        boolean isRemember = pref.getBoolean("remember_password",false);
        if(isRemember){
            String account = pref.getString("account","");
            String password = pref.getString("password","");
            edt_account.setText(account);
            edt_password.setText(password);
            rememberPassword.setChecked(true);
        }
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String account = edt_account.getText().toString();
                String password = edt_password.getText().toString();
                if(account.equals("admin")&&password.equals("12345")){
                    editor = pref.edit();
                    if(rememberPassword.isChecked()){
                        editor.putBoolean("remember_password",true);
                        editor.putString("account",account);
                        editor.putString("password",password);
                    }else{ editor.clear();
                    }
                    editor.apply();
                    Intent intent = new Intent(MainActivity.this,SecondActivity.class);
                    startActivity(intent);
                    finish();
                      } else{
                    Toast.makeText(MainActivity.this, "Not right!", Toast.LENGTH_SHORT).show();
                }
}       });



    }
}

搞定！