MainActivity.java
package com.example.restaurantapp;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;
import java.util.HashMap;
public class MainActivity extends AppCompatActivity {
Spinner categorySpinner, itemSpinner;
TextView priceTextView;
Button addButton, checkoutButton;
int totalCost = 0;
DatabaseHelper dbHelper;
ArrayList<String> categoryList = new ArrayList<>();
HashMap<String, Integer> categoryMap = new HashMap<>();
ArrayList<String> itemList = new ArrayList<>();
HashMap<String, Integer> itemPriceMap = new HashMap<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbHelper = new DatabaseHelper(this);
categorySpinner = findViewById(R.id.categorySpinner);
itemSpinner = findViewById(R.id.itemSpinner);
priceTextView = findViewById(R.id.priceTextView);
addButton = findViewById(R.id.addButton);
checkoutButton = findViewById(R.id.checkoutButton);
loadCategories();
categorySpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (position > 0) {
String category = categoryList.get(position);
loadItems(categoryMap.get(category));
}
}
@Override public void onNothingSelected(AdapterView<?> parent) {}
});
itemSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (position >= 0 && position < itemList.size()) {
String item = itemList.get(position);
int price = itemPriceMap.get(item);
priceTextView.setText("Price: $" + price);
}
}
@Override public void onNothingSelected(AdapterView<?> parent) {}
});
addButton.setOnClickListener(v -> {
String item = (String) itemSpinner.getSelectedItem();
if (item != null) {
totalCost += itemPriceMap.get(item);
Toast.makeText(MainActivity.this, "Item added! Total: $" + totalCost, Toast.LENGTH_SHORT).show();
}
});
checkoutButton.setOnClickListener(v -> {
Intent intent = new Intent(MainActivity.this, SummaryActivity.class);
intent.putExtra("total", totalCost);
startActivity(intent);
});
}
private void loadCategories() {
categoryList.clear();
categoryList.add("Select Category");
Cursor cursor = dbHelper.getCategories();
while (cursor.moveToNext()) {
int id = cursor.getInt(0);
String name = cursor.getString(1);
categoryList.add(name);
categoryMap.put(name, id);
}
cursor.close();
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, categoryList);
categorySpinner.setAdapter(adapter);
}
private void loadItems(int categoryId) {
itemList.clear();
itemPriceMap.clear();
Cursor cursor = dbHelper.getItemsByCategoryId(categoryId);
while (cursor.moveToNext()) {
String name = cursor.getString(2);
int price = cursor.getInt(3);
itemList.add(name);
itemPriceMap.put(name, price);
}
cursor.close();
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, itemList);
itemSpinner.setAdapter(adapter);
}
private static class DatabaseHelper extends SQLiteOpenHelper {
public static final String DB_NAME = "restaurant.db";
public static final int DB_VERSION = 1;
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE IF NOT EXISTS categories (id INTEGER PRIMARY KEY, name TEXT)");
db.execSQL("CREATE TABLE IF NOT EXISTS items (id INTEGER PRIMARY KEY, category_id INTEGER, name TEXT, price INTEGER)");
db.execSQL("INSERT INTO categories (name) VALUES ('Drinks'), ('Main Course'), ('Dessert')");
db.execSQL("INSERT INTO items (category_id, name, price) VALUES " +
"(1, 'Coke', 2), (1, 'Water', 1), (1, 'Juice', 3), " +
"(2, 'Burger', 5), (2, 'Pizza', 8), (2, 'Pasta', 7), " +
"(3, 'Ice Cream', 4), (3, 'Cake', 5), (3, 'Pudding', 3)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS items");
db.execSQL("DROP TABLE IF EXISTS categories");
onCreate(db);
}
public Cursor getCategories() {
return getReadableDatabase().rawQuery("SELECT * FROM categories", null);
}
public Cursor getItemsByCategoryId(int categoryId) {
return getReadableDatabase().rawQuery("SELECT * FROM items WHERE category_id = ?", new String[]{String.valueOf(categoryId)});
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="24dp"
android:gravity="center_horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Select Category"
android:textSize="18sp"
android:layout_marginBottom="8dp" />
<Spinner
android:id="@+id/categorySpinner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="24dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Select Item"
android:textSize="18sp"
android:layout_marginBottom="8dp" />
<Spinner
android:id="@+id/itemSpinner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="24dp"/>
<TextView
android:id="@+id/priceTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Price: $0"
android:textSize="20sp"
android:textStyle="bold"
android:layout_marginBottom="32dp"/>
<Button
android:id="@+id/addButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add Item"
android:layout_marginBottom="20dp"
android:padding="12dp"/>
<Button
android:id="@+id/checkoutButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Checkout"
android:padding="12dp"/>
</LinearLayout>
SummaryActivity.java
package com.example.restaurantapp;
import android.os.Bundle;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
public class SummaryActivity extends AppCompatActivity {
@override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_summary);
int total = getIntent().getIntExtra("total", 0);
TextView summaryText = findViewById(R.id.summaryText);
summaryText.setText("Total cost: $" + total);
}
}
activity_summary.xml
<?xml version="1.0" encoding="utf-8"?>
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="32dp"
android:gravity="center">
<TextView
android:id="@+id/summaryText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Total cost: $0"
android:textSize="28sp"
android:textStyle="bold"
android:textColor="#000000"
android:layout_marginTop="20dp"/>
androidmanifest.xml
only if required
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:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.Restaurantapp"
tools:targetApi="31">
android:name=".MainActivity"
android:exported="true">
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".SummaryActivity"></activity>
</application>
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