Project structure overview in React Native - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the main app component from the correct file.

React Native

import App from './[1]';

Drag options to blanks, or click blank then click option'

AMain

Bapp

Cmain

DApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'app' instead of 'App' causes import errors.

Trying to import from 'Main' when the file is named 'App.js'.

The main app component is usually in a file named App.js, so we import from './App'.

2fill in blank

medium

Complete the code to register the main app component with AppRegistry.

React Native

AppRegistry.registerComponent('[1]', () => App);

Drag options to blanks, or click blank then click option'

AappName

Bname

CMyApp

DMainApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using a hardcoded string that does not match app.json causes the app not to load.

Using variable names like 'MainApp' without defining them.

The app name is usually imported from app.json as appName and used here to register the app.

3fill in blank

hard

Fix the error in the import statement for React Native components.

React Native

import { View, Text, [1] } from 'react-native';

Drag options to blanks, or click blank then click option'

ATouchableOpacity

Bbutton

CButton

Dtouchableopacity

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase component names causes import errors.

Confusing similar component names.

React Native components use PascalCase names like TouchableOpacity. Lowercase names cause errors.

4fill in blank

hard

Fill both blanks to create a simple functional component that returns a Text element.

React Native

const [1] = () => {
  return <[2]>Hello!</[2]>;
};

Drag options to blanks, or click blank then click option'

AGreeting

BView

CText

DApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase component names.

Using View instead of Text to display text.

The component name should be Greeting and it returns a Text element to display text.

5fill in blank

hard

Fill all three blanks to export the component as default and import React.

React Native

import [1] from 'react';

const Greeting = () => <Text>Hello!</Text>;

export [2] Greeting;

// Also import [3] from react-native for UI components

Drag options to blanks, or click blank then click option'

AReact

Bdefault

CView

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to import React causes JSX errors.

Using named export instead of default export here.

Not importing UI components like View or Text.

You import React to use JSX, export the component as default, and import View from react-native for UI layout.

Practice

1. In a typical React Native project, where should you place your main app code for better organization?

easy

A. Inside the android folder

B. Directly in the root folder

C. Inside a folder named src

D. Inside the ios folder

Solution

1. Step 1: Understand folder roles

   The android and ios folders contain platform-specific native code, not app logic.

2. Step 2: Identify app code location

   App code is best organized inside a src folder to keep it separate and clear.

3. Final Answer:

   Inside a folder named src -> Option C

4. Quick Check:

   App code = src folder [OK]

Hint: App code goes in src folder, not platform folders [OK]

Common Mistakes:

• Putting app code inside android or ios folders
• Keeping all code in the root folder without organization

2. Which of the following is the correct folder name for platform-specific Android code in a React Native project?

easy

A. android

B. android_src

C. AndroidCode

D. androidApp

Solution

1. Step 1: Recall standard folder names

   React Native uses android as the folder name for Android platform code by default.

2. Step 2: Compare options

   Only android matches the exact folder name used by React Native.

3. Final Answer:

   android -> Option A

4. Quick Check:

   Android folder = android [OK]

Hint: Platform folders are named exactly android and ios [OK]

Common Mistakes:

• Using camelCase or underscores in platform folder names
• Confusing app code folder with platform folders

3. Given this React Native project structure:

myApp/
├── android/
├── ios/
├── src/
│   └── App.js
└── package.json

Where will the main app component be located?

medium

A. Directly in the root folder

B. Inside ios folder

C. Inside android folder

D. Inside src folder

Solution

1. Step 1: Analyze folder contents

   The src folder contains App.js, which is the main app component file.

2. Step 2: Understand platform folders

   The android and ios folders hold native code, not React Native components.

3. Final Answer:

   Inside src folder -> Option D

4. Quick Check:

   Main app component = src/App.js [OK]

Hint: Main app code lives in src, not platform folders [OK]

Common Mistakes:

• Assuming main app code is inside android or ios
• Looking for app code in the root folder

4. You see this error when running your React Native app: "Cannot find module './App'". Your project structure is:

myApp/
├── android/
├── ios/
├── app/
│   └── App.js
└── package.json

What is the likely cause?

medium

A. The package.json file is corrupted

B. The app code is inside app folder but should be in src

C. The android folder is missing App.js

D. The ios folder is empty

Solution

1. Step 1: Identify folder mismatch

   The app code is in app folder, but React Native expects it in src or root by default.

2. Step 2: Understand module resolution

   Since the code is not where expected, the bundler cannot find ./App module.

3. Final Answer:

   App code is inside app folder but should be in src -> Option B

4. Quick Check:

   App folder mismatch = module not found error [OK]

Hint: App code folder must match import paths exactly [OK]

Common Mistakes:

• Ignoring folder naming conventions
• Assuming platform folders hold app code
• Not checking import paths

5. You want to add a new feature to your React Native app. Which project structure change helps keep your code organized and maintainable?

hard

A. Create a new folder inside src for the feature components

B. Add all new files directly to the root folder

C. Put new feature files inside the android folder

D. Mix new feature files with existing files in ios folder

Solution

1. Step 1: Understand best practices for organization

   Keeping feature code inside src in dedicated folders helps maintain clarity and separation.

2. Step 2: Avoid mixing platform and app code

   Platform folders android and ios are for native code, not React Native components.

3. Final Answer:

   Create a new folder inside src for the feature components -> Option A

4. Quick Check:

   Organize features inside src for maintainability [OK]

Hint: Keep features inside src in separate folders [OK]

Common Mistakes:

• Adding app code to platform folders
• Cluttering root folder with many files
• Not grouping related files