Why core components build native UIs in React Native - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the core component that builds native UI in React Native.

React Native

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

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

AButton

BView

CTextInput

DStyleSheet

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing components that are for input or styling, not containers.

The View component is a core React Native component that builds native UI containers.

2fill in blank

medium

Complete the code to create a native text element using a core component.

React Native

return <[1]>Hello, world!</[1]>;

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

AText

BView

CScrollView

DImage

Attempts:

3 left

💡 Hint

Common Mistakes

Using View instead of Text for displaying text.

The Text component renders native text elements in React Native.

3fill in blank

hard

Fix the error in the code to correctly use a core component that builds native UI.

React Native

const App = () => {
  return (
    <[1]>Welcome!</[1]>
  );
};

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

AText

BButton

CTouchableOpacity

DImage

Attempts:

3 left

💡 Hint

Common Mistakes

Using Button or Image components to display text.

The Text component is the correct core component to display text content natively.

4fill in blank

hard

Fill both blanks to create a native UI container with a text child.

React Native

return (
  <[1]>
    <[2]>Native UI</[2]>
  </[1]>
);

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

AView

BText

CScrollView

DImage

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping container and text components.

View is used as a container, and Text displays native text inside it.

5fill in blank

hard

Fill all three blanks to build a native UI with a container, text, and a button.

React Native

return (
  <[1]>
    <[2]>Press me</[2]>
    <[3] title="Click" onPress={() => alert('Clicked!')} />
  </[1]>
);

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

AView

BText

CButton

DTouchableOpacity

Attempts:

3 left

💡 Hint

Common Mistakes

Using TouchableOpacity instead of Button for the button component.

View is the container, Text shows text, and Button is the native clickable button.

Practice

1. Why do React Native core components create a better user experience on mobile devices?

easy

A. Because they only work on Android devices

B. Because they use web views to display content

C. Because they render real native UI elements on iOS and Android

D. Because they require manual native code for UI

Solution

1. Step 1: Understand core components role

   Core components like View and Text map directly to native UI elements on each platform.

2. Step 2: Compare with other methods

   Unlike web views, core components use native widgets, making apps faster and smoother.

3. Final Answer:

   Because they render real native UI elements on iOS and Android -> Option C

4. Quick Check:

   Native UI = Better user experience [OK]

Hint: Core components map to native widgets, not web views [OK]

Common Mistakes:

• Thinking React Native uses web views for UI
• Believing core components only work on Android
• Assuming manual native code is always needed

2. Which of the following is the correct way to create a text element using React Native core components?

easy

A. Hello World

B. Hello World

C. Hello World

D. Hello World

Solution

1. Step 1: Identify React Native core text component

   React Native uses Text with capital T as a core component for displaying text.

2. Step 2: Check JSX syntax

   Lowercase text or HTML tags like div and p are not valid in React Native JSX.

3. Final Answer:

   <Text>Hello World</Text> -> Option B

4. Quick Check:

   Use capitalized core components [OK]

Hint: React Native core components start with uppercase letters [OK]

Common Mistakes:

• Using lowercase tags like <text>
• Using HTML tags like <div> or <p>
• Confusing React Native with web React syntax

3. What will the following React Native code display on a device screen?

import React from 'react';
import { View, Text } from 'react-native';

export default function App() {
  return (
    
      Welcome!
    
  );
}

medium

A. A native screen showing the text 'Welcome!'

B. An error because <View> is not a valid component

C. A blank screen with no text

D. A web page with 'Welcome!' inside a div

Solution

1. Step 1: Analyze component imports

   The code imports View and Text from React Native core components, which render native UI elements.

2. Step 2: Understand JSX output

   The App function returns a View containing a Text element with 'Welcome!'. This displays as native UI text on the device.

3. Final Answer:

   A native screen showing the text 'Welcome!' -> Option A

4. Quick Check:

   Core components render native UI [OK]

Hint: Core components produce native UI, not web elements [OK]

Common Mistakes:

• Thinking <View> is invalid in React Native
• Expecting web HTML output
• Assuming no text will show without styles

4. Identify the error in this React Native code snippet:

import React from 'react';
import { View, Text } from 'react-native';

export default function App() {
  return (
    
      Hello
    
  );
}

medium

A. JSX cannot return multiple elements

B. Text should be lowercase

C. Missing import for view

D. view should be capitalized as View

Solution

1. Step 1: Check component capitalization

   React Native core components must start with uppercase letters. Here, view is lowercase, causing an error.

2. Step 2: Confirm correct usage

   Changing view to View fixes the error. Text is correctly capitalized.

3. Final Answer:

   <view> should be capitalized as <View> -> Option D

4. Quick Check:

   Core components start uppercase [OK]

Hint: Always capitalize React Native core components [OK]

Common Mistakes:

• Using lowercase component names
• Confusing import errors with JSX errors
• Thinking multiple JSX elements need wrapping

5. You want to create a button that looks native on both iOS and Android using React Native core components. Which approach best achieves this?

hard

A. Use the Button core component which renders native buttons on each platform

B. Use a View with a Text and style it manually

C. Use an HTML button tag inside React Native JSX

D. Write separate native code for iOS and Android buttons

Solution

1. Step 1: Identify React Native core button component

   The Button core component automatically renders native buttons on iOS and Android.

2. Step 2: Compare alternatives

   Styling a View and Text manually won't produce native behavior. HTML button is invalid in React Native. Writing separate native code is complex and unnecessary.

3. Final Answer:

   Use the <Button> core component which renders native buttons on each platform -> Option A

4. Quick Check:

   Core components provide native UI easily [OK]

Hint: Use core <Button> for native look on both platforms [OK]

Common Mistakes:

• Trying to use HTML tags in React Native
• Manually styling views instead of using core Button
• Thinking native code is always required