count down timer in react native with code examples

Countdown timers have become more and more prevalent in various applications, from games to productivity applications and e-commerce platforms. For a wide variety of use cases, a countdown timer is an important function. React Native, which is a popular library in the development of mobile applications, provides the perfect way to implement countdown timers in mobile applications.

React Native, an open-source framework created by Facebook, enables developers to create mobile applications for iOS and Android platforms from a single codebase. React Native development is based on React.js, a JavaScript library that enables straightforward, fast, and dynamic development for web-based applications.

In this article, we will show how to create a countdown timer in React Native using the expo-cli. This article is structured as follows:

Setting up an environment for creating a countdown timer in React Native.
Creating a countdown timer in React Native with code examples.
Changing the look and feel of the countdown timer using styling in React Native.

Setting Up the Environment for Creating a Countdown Timer in React Native

Before starting to create a countdown timer in React Native, you will need to set up your development environment. Follow the steps below to set up an environment for creating a countdown timer in React Native:

Step 1: Install Node.js and npm on your computer if you haven't already done so. To verify that npm is installed, run the following command in your terminal window:

npm -v

Step 2: Install the expo-cli globally using npm using the below command.

npm install -g expo-cli

Step 3: Create a new project using expo init and specify your project name, choose a template like blank and press enter.

expo init countdowntimer

This command creates a new project named ‘countdowntimer’ in your current directory.

Step 4: After creating your project, navigate to the project directory using the cd command:

cd countdowntimer

Step 5: Use the command below to start the development server.

npm start

This command starts the development environment where you can create your React Native project.

Creating a Countdown Timer in React Native with Code Examples

Now that you have set up your environment for developing a countdown timer in React Native, follow the below steps to create a countdown timer in React Native.

Step 1: Import the required components from the ‘react-native’ module.

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

Step 2: Create a functional component named ‘CountDownTimer' and define a state variable named ‘timerValue’ and assign it a default value of 60 seconds.

const CountDownTimer = () => {
const [timerValue, setTimerValue] = useState(60);

Step 3: Create a function named ‘startTimer()’ that will be called when the countdown timer is started. This function will reduce the value of ‘timerValue’ each second.

const startTimer = () => {
setInterval(() => {
setTimerValue(timerValue – 1);
}, 1000);
}

Step 4: Use an ‘useEffect()’ hook to start the timer when the component is loaded.

useEffect(() => {
startTimer();
}, []);

Step 5: Use the ‘StyleSheet’ module to define the style of the countdown timer, including color, font size, and alignment.

const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'center',
justifyContent: 'center',
backgroundColor: '#fff',
},
timer: {
fontSize: 70,
color: 'red',
},
});

Step 6: Use the ‘View’ and ‘Text’ components to display the countdown timer on the screen.

{timerValue}

Step 7: Open your project in the Expo Go app or in the Android or iOS emulator to view the countdown timer.

Congratulations! You have created a simple countdown timer in React Native. However, the style of the countdown timer needs to be updated to match the look and feel of the application.

Changing the Look and Feel of the Countdown Timer using Styling in React Native

React Native provides a straightforward way to style components. Let's see how to style the countdown timer created above.

Step 1: Update the ‘container’ style property to make the countdown timer occupy the entire screen.

container: {
flex: 1,
alignItems: 'center',
justifyContent: 'center',
backgroundColor: '#7DBBF1',
height: '100%',
},

Step 2: Update the ‘timer’ style property to change the font color and size. You can also use font families and other font styles.

timer: {
fontSize: 150,
color: 'white',
fontFamily:'HelveticaNeue-Thin',
fontWeight: 'bold',
},

Step 3: Save the changes and reload the application to view the updated design.

With these simple updates, the countdown timer now looks great and fits well with the overall design and feel.

Conclusion

In this article, we demonstrated how to create a countdown timer in React Native using the expo-cli and provided detailed explanations of each step. We also showed how to style the countdown timer to match the look and feel of the application. As a developer, you can take this technique and integrate countdown timers to your mobile applications, either for gaming purposes or productivity purposes. With React Native, integrating a countdown timer is simple, so start using React Native to build your next mobile application, and make the most of the countdown timer feature!

I'd be happy to provide more information about the previous topics.

In the article about "Countdown Timer in React Native with Code Examples", we showed how to create a simple countdown timer using React Native and the expo-cli. However, there are several other methods you can use to create countdown timers in React Native, including using third-party libraries and custom components.

One popular third-party library for creating countdown timers in React Native is react-native-countdown-component. This library provides an easy-to-use API for creating countdown timers and includes support for custom styling. Here's an example of how to use react-native-countdown-component:

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

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});

const CountdownTimer = () => (
  <View style={styles.container}>
    <CountdownCircleTimer
      isPlaying
      duration={30}
      colors={[
        ['#004777', 0.4],
        ['#F7B801', 0.4],
        ['#A30000', 0.2],
      ]}
      onComplete={() => console.log('Countdown finished')}
    />
  </View>
);

export default CountdownTimer;

In addition to third-party libraries, you can also create custom components for countdown timers. This approach can be useful if you need a more customized timer or want to reuse the component across multiple screens. Here's an example of how to create a custom countdown timer component:

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

const CountdownTimer = ({ duration, onComplete }) => {
  const [timerValue, setTimerValue] = useState(duration);

  useEffect(() => {
    const interval = setInterval(() => {
      setTimerValue(prevValue => prevValue - 1);
    }, 1000);
    return () => clearInterval(interval);
  }, []);

  useEffect(() => {
    if (timerValue === 0) {
      onComplete();
    }
  }, [timerValue]);

  return <Text>{timerValue}</Text>;
};

export default CountdownTimer;

Using this custom component, you can pass in a duration and a function to be called when the timer completes. Here's an example of how to use the custom component:

import React from 'react';
import { View } from 'react-native';
import CountdownTimer from './CountdownTimer';

const MyScreen = () => (
  <View>
    <CountdownTimer
      duration={30}
      onComplete={() => console.log('Countdown finished')}
    />
  </View>
);

export default MyScreen;

Overall, whether you choose to use a third-party library or create a custom component, there are many ways to create countdown timers in React Native. By using these techniques, you can add dynamic and engaging features to your mobile applications.

count down timer in react native with code examples

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Ahmed Zakaria

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Ahmed Zakaria

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