Why advanced UI creates polished apps in React Native - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple button with a label in React Native.

React Native

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

export default function App() {
  return (
    <View>
      <Button title=[1] onPress={() => alert('Clicked!')} />
    </View>
  );
}

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

AClick Me

B'Click Me'

C"Click Me"

DclickMe

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string

Using a variable name without defining it

The title prop requires a string wrapped in quotes. Using single quotes like 'Click Me' is correct.

2fill in blank

medium

Complete the code to apply a background color style to the View component.

React Native

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

export default function App() {
  return (
    <View style={styles.container} />
  );
}

const styles = StyleSheet.create({
  container: {
    backgroundColor: [1]
  }
});

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

A'#3498db'

B3498db

Cblue

DbackgroundColor

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting quotes around the color code

Using a color name without quotes

Colors in React Native styles must be strings, so '#3498db' is correct.

3fill in blank

hard

Fix the error in the code to correctly display a text label inside a View.

React Native

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

export default function App() {
  return (
    <View>
      <Text[1]>Hello, world!</Text>
    </View>
  );
}

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

A style={{ fontSize: 20 }}

B style=fontSize: 20

C style={fontSize: 20}

D style='fontSize: 20'

Attempts:

3 left

💡 Hint

Common Mistakes

Using single curly braces without an object

Using quotes instead of curly braces

The style prop must be an object inside double curly braces, so style={{ fontSize: 20 }} is correct.

4fill in blank

hard

Fill both blanks to create a styled button with padding and a background color.

React Native

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

export default function App() {
  return (
    <TouchableOpacity style={{padding: [1], backgroundColor: [2]>
      <Text>Press me</Text>
    </TouchableOpacity>
  );
}

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

A12

B'#e74c3c'

C12px

Dred

Attempts:

3 left

💡 Hint

Common Mistakes

Using '12px' instead of 12 for padding

Using color names without quotes

Padding should be a number without units, and backgroundColor should be a string color code.

5fill in blank

hard

Fill all three blanks to create a responsive text input with placeholder and border color.

React Native

import React from 'react';
import { TextInput, StyleSheet } from 'react-native';

export default function App() {
  return (
    <TextInput
      style={{ borderWidth: [1], borderColor: [2], padding: [3] }}
      placeholder="Enter text"
    />
  );
}

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

A1

B'#2ecc71'

C10

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using strings for borderWidth or padding

Omitting quotes around borderColor

Border width is a number (2), border color is a string color code, and padding is a number (10).

Practice

1. Why does adding animations in a React Native app improve user experience?

easy

A. Animations slow down the app and confuse users.

B. Animations are only for decoration and do not affect usability.

C. Animations increase the app size without benefits.

D. Animations make the app feel smoother and more engaging.

Solution

1. Step 1: Understand the role of animations in UI

   Animations provide visual feedback and smooth transitions that help users understand app behavior.

2. Step 2: Connect animations to user engagement

   Smoother and engaging animations keep users interested and make the app feel polished.

3. Final Answer:

   Animations make the app feel smoother and more engaging. -> Option D

4. Quick Check:

   Animations improve experience = B [OK]

Hint: Animations enhance feel and engagement [OK]

Common Mistakes:

• Thinking animations slow down the app
• Believing animations are just decoration
• Ignoring user engagement benefits

2. Which of the following is the correct way to add a simple button in React Native?

easy

A. alert('Hello')} />

B. alert('Hello')} />

C. alert('Hello')} />

D. alert('Hello')} />

Solution

1. Step 1: Identify correct React Native button syntax

   React Native uses <Button> with 'title' prop and 'onPress' event.

2. Step 2: Check each option for correct props and tags

   <Button title='Click me' onPress={() => alert('Hello')} /> uses correct tag and props; others use invalid tags or props.

3. Final Answer:

   <Button title='Click me' onPress={() => alert('Hello')} /> -> Option A

4. Quick Check:

   React Native Button = <Button title='Click me' onPress={() => alert('Hello')} /> [OK]

Hint: React Native uses <Button> with title and onPress [OK]

Common Mistakes:

• Using lowercase <button> instead of <Button>
• Using 'text' instead of 'title' prop
• Using 'onClick' instead of 'onPress'

3. What will be the visible result of this React Native code snippet?

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

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

const styles = StyleSheet.create({
  container: { flex: 1, justifyContent: 'center', alignItems: 'center' },
  text: { fontSize: 24, color: 'blue' }
});

medium

A. A blank screen with no text visible

B. A full screen with centered blue text 'Welcome!'

C. An error because styles are not applied correctly

D. A small box with black text 'Welcome!' at top left

Solution

1. Step 1: Analyze the container style

   The container uses flex:1 to fill screen and centers content vertically and horizontally.

2. Step 2: Analyze the text style

   The text has font size 24 and blue color, so it will appear large and blue.

3. Final Answer:

   A full screen with centered blue text 'Welcome!' -> Option B

4. Quick Check:

   Centered blue text = D [OK]

Hint: flex:1 + center styles = centered content [OK]

Common Mistakes:

• Assuming text is black by default
• Thinking styles cause errors
• Ignoring flexbox centering

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
      World
    
  );
}

const styles = StyleSheet.create({
  container: { flex: 1 }
});

medium

A. The code is correct and will render 'Hello' and 'World'.

B. Multiple <Text> components inside <View> are not allowed.

C. Missing import of StyleSheet causes error.

D. The <View> tag is not closed properly.

Solution

1. Step 1: Check imports and usage

   The code uses StyleSheet.create but does not import StyleSheet from 'react-native'.

2. Step 2: Verify JSX structure

   Multiple <Text> inside <View> is allowed and <View> is properly closed.

3. Final Answer:

   Missing import of StyleSheet causes error. -> Option C

4. Quick Check:

   Missing StyleSheet import = A [OK]

Hint: Import all used modules like StyleSheet [OK]

Common Mistakes:

• Thinking multiple <Text> tags are invalid
• Ignoring missing imports
• Assuming JSX tags are not closed

5. You want to create a polished React Native app with a button that changes color smoothly when pressed. Which approach best achieves this advanced UI effect?

hard

A. Use TouchableOpacity with animated opacity change on press.

B. Use a simple Button component with no animation.

C. Change button color instantly without animation on press.

D. Use Text component styled as a button without interaction.

Solution

1. Step 1: Identify how to animate button color on press

   TouchableOpacity supports animated opacity changes, giving smooth visual feedback.

2. Step 2: Compare options for polished UI

   Simple Button or instant color change lacks smooth animation; Text component lacks interaction.

3. Final Answer:

   Use TouchableOpacity with animated opacity change on press. -> Option A

4. Quick Check:

   Animated touch feedback = C [OK]

Hint: TouchableOpacity enables smooth press animations [OK]

Common Mistakes:

• Using Button without animation
• Changing color instantly without animation
• Using Text without interaction