android外卖点餐界面（期末作业）

效果展示：
在这里插入图片描述

AndroidMainFest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.EndActivity"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".Register"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".Login"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

FoodItem.java

package com.lzcu.endactivity;

public class FoodItem {
    private String name;        // 食品名称
    private double price;       // 食品价格
    private boolean isVegetarian;  // 是否素食

    public FoodItem(String name, double price) {
        this.name = name;
        this.price = price;

    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }
}

package com.lzcu.endactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


public class Login extends AppCompatActivity {

    Button login_but,register_but;
    TextView touchScreen;
    EditText Account_2,pwd;
    MyDatabaseHelper myDatabaseHelper;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //按钮组件
        login_but = findViewById(R.id.login);
        register_but = findViewById(R.id.register);
        //编辑框
        Account_2 = findViewById(R.id.UserName);
        pwd =findViewById(R.id.Pwd);
        //数据库
        myDatabaseHelper = new MyDatabaseHelper(this);
        myDatabaseHelper.getWritableDatabase();//只读
        //登录
        login_but.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                String acc = Account_2.getText().toString();
                String pwd1 =pwd.getText().toString();
                //获取数据库数据，判断用户名是否在库
                Cursor result = myDatabaseHelper.find();
                int a=0;
                int b=0;
                for (result.moveToFirst();!result.isAfterLast();result.moveToNext())
                {
                    @SuppressLint("Range") String account_1=result.getString(result.getColumnIndex("Account"));
                    @SuppressLint("Range") String pwd_1=result.getString(result.getColumnIndex("Password"));
                    if (Account_2.getText().toString().equals(account_1) && pwd.getText().toString().equals(pwd_1))
                        a=1;
                    if (Account_2.getText().toString().equals(account_1))
                        b=1;
                }
                if (b==1)
                {
                    if (!Account_2.getText().toString().equals("") && !pwd.getText().toString().equals(""))
                    {
                        if(a==1)
                        {
                            Intent intent = new Intent(Login.this, MainActivity.class);
                            startActivity(intent);
                            finish();
                            Toast.makeText(Login.this, "登入成功", Toast.LENGTH_SHORT).show();
                        }
                        else
                            Toast.makeText(getApplicationContext(),"密码错误！", Toast.LENGTH_SHORT).show();
                    }else
                        Toast.makeText(getApplicationContext(),"用户名或密码不能为空！", Toast.LENGTH_SHORT).show();
                }
                else
                    Toast.makeText(Login.this, "账号不存在，请注册！", Toast.LENGTH_SHORT).show();
                //关闭游标
                result.close();

            }
        });
        //注册
        register_but.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                //显示注册界面
                Intent intent = new Intent(Login.this, Register.class);
                //启动显示修改界面
                startActivity(intent);
                finish();
            }
        });
    }
}

MainActivity.java

package com.lzcu.endactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    public TextView txtCartItems;
    public Button btnCheckout;
    public ArrayList<FoodItem> cartItems = new ArrayList<>();
    public double totalPrice = 0;
    private ListView menu_list;
    private List<String> mDataList;
    private ArrayAdapter<String> mAdapter;
    private EditText mEditText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        txtCartItems = findViewById(R.id.txt_cart_items);
        btnCheckout = findViewById(R.id.btn_checkout);

        //初始化
        // 初始化 ListView 和 数据源
        menu_list = findViewById(R.id.menu_list);
        mDataList = new ArrayList<>();

        // 添加测试数据
        mDataList.add("汉堡 22.5");
        mDataList.add("薯条 12.0");
        mDataList.add("热干面 8.0");
        mDataList.add("麻辣香锅 59.0");
        mDataList.add("鱼香肉丝 38.0");
        mDataList.add("大盘鸡 48.0");
        mDataList.add("炒粉丝 11.0");
        mDataList.add("毛血旺 58.0");

        // 创建适配器
        mAdapter = new ArrayAdapter<>(this,
                android.R.layout.simple_list_item_1, mDataList);

        // 设置适配器
        menu_list.setAdapter(mAdapter);

        // 设置列表项点击事件
        menu_list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Toast.makeText(MainActivity.this, "你选择了" + mDataList.get(i),
                        Toast.LENGTH_SHORT).show();
                // 获取 editText 控件
                mEditText = findViewById(R.id.editText);

                mEditText.append(mDataList.get(i));
//                mEditText.setText("你选择了"+mDataList.get(i)+"吗？");
                // 加入购物车的逻辑
                FoodItem item1 = new FoodItem("汉堡", 22.5);
                FoodItem item2 = new FoodItem("薯条", 12.0);
                addToCart(item1);
                addToCart(item2);
            }
        });


        // 更新购物车信息
        updateCart();

        // 结算按钮的点击事件
        btnCheckout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkout();
            }
        });
    }

    // 添加商品到购物车
    private void addToCart(FoodItem item) {
        cartItems.add(item);
        totalPrice += item.getPrice();
    }

    // 更新购物车信息
    private void updateCart() {
        String cartText = "购物车(" + cartItems.size() + "): ¥" + totalPrice;
        txtCartItems.setText(cartText);
    }

    // 结算
    private void checkout() {
        // 将购物车中的商品生成订单，进行结算等操作
        Toast.makeText(this, "订单已提交，感谢您的惠顾！", Toast.LENGTH_SHORT).show();
        cartItems.clear();
        totalPrice = 0;
        updateCart();
    }
}

MyDatabaseHelper.java

package com.lzcu.endactivity;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import androidx.annotation.Nullable;


public class MyDatabaseHelper extends SQLiteOpenHelper
{
    //声明数据库的名字和表名
    private static final String DATABASENAME = "Practical.db" ;	// 数据库名称
    private static final int DATABASEVERSION = 1 ;
    private static final String TABLE_USERNAME = "User" ;	// 用户表名称

    public MyDatabaseHelper(@Nullable Context context)
    {
        super(context, DATABASENAME, null, DATABASEVERSION);
    }
    @Override
    public void onCreate(SQLiteDatabase db)
    {
        //创建数据库用户表，并添加三个字段id,Account,Password
        String sqlString="create table "+ TABLE_USERNAME+"( id integer primary key autoincrement,Account varchar(255),Password varchar(255))";
        db.execSQL(sqlString);
    }
    //注册
    public  void Register(String Account,String Password)
    {
        SQLiteDatabase db=super.getWritableDatabase();
        String sqlString="insert into "+TABLE_USERNAME+"(Account,Password) values (?,?)";
        //构造占位符的参数数组
        Object args[]=new Object[]{Account,Password};
        db.execSQL(sqlString,args);//此方法执行的sql语句主要有创建、插入、修改、删除等
        db.close();
    }
    //查询账号的方法
    public Cursor find()
    {
        SQLiteDatabase db=super.getWritableDatabase();
        String sqlString="select * from User;";
        //执行查询，返回数据给游标
        Cursor result =db.rawQuery(sqlString,null);
        return result;
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    }
}

package com.lzcu.endactivity;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

public class Register extends AppCompatActivity {
    Button register_lj,back;
    TextView touchScreen;
    EditText Account,Pwd1,Pwd2;
    MyDatabaseHelper myDatabaseHelper;
    ArrayList<User> data = new ArrayList<User>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.register);
        //数据库
        myDatabaseHelper = new MyDatabaseHelper(this);
        //按钮组件
        register_lj =findViewById(R.id.register_but);
        back =findViewById(R.id.back);
        //编辑框
        Account = findViewById(R.id.register_name);
        Pwd1 = findViewById(R.id.register_pwd);
        Pwd2 = findViewById(R.id.register_pwd2);
        //立即注册
        register_lj.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                //获取输入的用户名和密码
                String name = Account.getText().toString().trim();
                String password = Pwd1.getText().toString().trim();
                //获取数据库数据，判断用户名是否已存在
                Cursor result = myDatabaseHelper.find();
                int a=0;
                if (!Account.getText().toString().equals(""))
                {
                    if (Account.getText().toString().length()<6)
                        Toast.makeText(Register.this, "账号创建不能少于6位", Toast.LENGTH_SHORT).show();
                    else if (Pwd1.getText().toString().length()<6)
                        Toast.makeText(Register.this, "密码设置不能少于6位", Toast.LENGTH_SHORT).show();
                    else
                    {
                        for (result.moveToFirst();!result.isAfterLast();result.moveToNext())
                        {
                            //判断数据库是否存在此对象
                            @SuppressLint("Range") String account_1 = result.getString(result.getColumnIndex("Account"));
                            if(Account.getText().toString().equals(account_1))
                            {
                                a=1;
                            }
                        }
                        //关闭游标
                        result.close();
                        if(!Pwd1.getText().toString().equals("") && !Pwd2.getText().toString().equals(""))
                        {
                            if ((Pwd1.getText().toString().equals(Pwd2.getText().toString()) && a==0))
                            {
                                myDatabaseHelper.Register(name,password);
                                Intent intent = new Intent(Register.this, Login.class);
                                startActivity(intent);
                                finish();
                                Toast.makeText(Register.this, "注册成功", Toast.LENGTH_SHORT).show();
                            }
                            else if (a==1)
                                Toast.makeText(getApplicationContext(),"账号已存在,请重新输入账号",Toast.LENGTH_SHORT).show();
                            else
                                Toast.makeText(getApplicationContext(),"两次密码输入不一致",Toast.LENGTH_SHORT).show();
                        } else
                            Toast.makeText(getApplicationContext(),"密码不能为空！",Toast.LENGTH_SHORT).show();
                    }

                } else
                    Toast.makeText(getApplicationContext(),"账号不能为空！",Toast.LENGTH_SHORT).show();
            }
        });
        //返回
        back.setOnClickListener(
                new View.OnClickListener()
                {
                    @Override
                    public void onClick(View v)
                    {
                        //显示注册界面
                        Intent intent = new Intent(Register.this, Login.class);
                        //启动显示修改界面
                        startActivity(intent);
                        finish();
                    }
                })
    }
}

User.java

package com.lzcu.endactivity;


public class User
{
    private int id;
    private String account;
    private String password;


    public User( ) {

    }
    public User(int id, String account, String password) {
        this.id = id;
        this.account = account;
        this.password = password;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getAccount() {
        return account;
    }

    public void setAccount(String account) {
        this.account = account;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".MainActivity"
    android:background="@drawable/img">

    <TextView
        android:id="@+id/text_top"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:text="外卖点餐"
        android:textColor="@color/black"
        android:textSize="30dp"
        android:textStyle="italic"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        />

    <EditText
        android:id="@+id/UserName"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="60dp"

        android:hint="请输入用户名"
        android:padding="15dp"
        android:singleLine="true"
        android:textSize="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/text_top" />

    <EditText
        android:id="@+id/Pwd"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:hint="请输入用户密码"
        android:inputType="textPassword"
        android:maxLength="16"
        android:padding="15dp"
        android:singleLine="true"
        android:textSize="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/UserName" />

    <Button
        android:id="@+id/login"
        android:layout_width="120dp"
        android:layout_height="60dp"
        android:layout_marginTop="30dp"
        android:text="登录"
        android:textStyle="bold"
        app:layout_constraintEnd_toStartOf="@+id/register"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/Pwd" />

    <Button
        android:id="@+id/register"
        android:layout_width="120dp"
        android:layout_height="60dp"
        android:layout_marginTop="30dp"
        android:text="注册"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/login"
        app:layout_constraintTop_toBottomOf="@+id/Pwd" />

</androidx.constraintlayout.widget.ConstraintLayout>

main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/img">

    <!-- 标题栏 -->
    <RelativeLayout
        android:id="@+id/title_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >

        <TextView
            android:id="@+id/title_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:text="外卖点餐系统"
            android:textSize="22sp"
            android:textColor="#ffffff" />
    </RelativeLayout>
    <!-- 菜单列表 -->

    <!-- 购物车和结算按钮 -->
    <ListView
        android:id="@+id/menu_list"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

    <RelativeLayout
        android:id="@+id/cart_layout"
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:layout_marginTop="10dp"
        android:background="#ffffff"
        android:padding="0dp">

        <TextView
            android:id="@+id/txt_cart_items"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="购物车(0): ¥0"
            android:textColor="#000000"
            android:textSize="18sp" />

        <Button
            android:id="@+id/btn_checkout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:text="结算"
            android:textColor="#ffffff"
            android:textSize="18sp" />
    </RelativeLayout>
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="70dp"
        android:layout_marginTop="10dp"
        android:background="#ffffff"
        android:padding="0dp">
        <EditText
            android:id="@+id/editText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_marginBottom="25dp"
            android:gravity="bottom"
            />
    </RelativeLayout>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".Login"
    android:background="@drawable/img"
    tools:ignore="MissingDefaultResource">

    <TextView
        android:id="@+id/text_top"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="90dp"
        android:text="注册界面"
        android:textColor="#141414"
        android:textSize="30dp"
        android:textStyle="italic"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/register_name"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="50dp"

        android:hint="请输入用户名"
        android:padding="15dp"
        android:singleLine="true"
        android:textSize="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/text_top" />

    <EditText
        android:id="@+id/register_pwd"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"

        android:hint="请输入用户密码"
        android:inputType="textPassword"
        android:maxLength="16"
        android:padding="15dp"
        android:singleLine="true"
        android:textSize="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/register_name" />

    <EditText
        android:id="@+id/register_pwd2"
        android:layout_width="300dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"

        android:hint="请确认密码"
        android:inputType="textPassword"
        android:maxLength="16"
        android:padding="15dp"
        android:singleLine="true"
        android:textSize="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.504"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/register_pwd" />

    <Button
        android:id="@+id/register_but"
        android:layout_width="120dp"
        android:layout_height="60dp"
        android:layout_marginTop="30dp"

        android:text="立即注册"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintEnd_toStartOf="@+id/back"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/register_pwd2" />

    <Button
        android:id="@+id/back"
        android:layout_width="120dp"
        android:layout_height="60dp"
        android:layout_marginTop="30dp"

        android:text="返回登录"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toEndOf="@+id/register_but"
        app:layout_constraintTop_toBottomOf="@+id/register_pwd2" />
</androidx.constraintlayout.widget.ConstraintLayout>