React Native Timer is a great way to manage time-based events in your app. In this tutorial, you will learn how to use React Native Timer and all of its features. 

![react native timer](https:&#x2F;&#x2F;devbrite.io&#x2F;media&#x2F;cover8.jpg)
## What is a Timer?

A timer is a special type of clock that is used to count down from a given time interval. It can be used to measure the duration of an event, or to track how long it takes for a user to complete a task. Timers are commonly used in interactive applications such as games, to ensure the user is not taking too long to complete a task. 

## When To Use a Timer in React Native?

React Native Timer can be used in any React Native project that requires a timer. Some common use cases are: 

- Creating a timer to track the duration of an event
- Counting down from a given time interval
- Tracking how long it takes for a user to complete a task
- Creating a game timer

## Setting up React Native Environment

Before you can start using React Native Timer, you need to set up your React Native environment. To do this, you will need to install the latest version of [React Native CLI](https:&#x2F;&#x2F;reactnative.dev&#x2F;docs&#x2F;environment-setup).

Once you have installed the React Native CLI, you can create a new React Native project by running the following command: 

&#96;&#96;&#96;
react-native init MyTimerApp
&#96;&#96;&#96;

This will create a new React Native project called &#96;MyTimerApp&#96;. Now you are ready to start using React Native Timer in your project.

## Building a Simple Timer App in React Native

Now that you have set up your React Native environment, you can start building a simple timer app. To do this, you will need to create a new React Native component called &#96;Timer&#96;.

The &#96;Timer&#96; component will be responsible for rendering the timer display and handling user interactions. To get started, open the &#96;MyTimerApp&#96; project in your code editor and create a new file called &#96;Timer.js&#96;. 

In the &#96;Timer.js&#96; file, import the &#96;StyleSheet&#96;, &#96;Text&#96;, and &#96;View&#96; components from the React Native library:

&#96;&#96;&#96;js
import React from &#x27;react&#x27;;
import { StyleSheet, Text, View } from &#x27;react-native&#x27;;
&#96;&#96;&#96;

Next, define the &#96;Timer&#96; component and add the &#96;render()&#96; method:

&#96;&#96;&#96;js
export default class Timer extends React.Component {
  render() {
    return (
      &lt;View&gt;
        &lt;Text&gt;Timer&lt;&#x2F;Text&gt;
      &lt;&#x2F;View&gt;
    );
  }
}
&#96;&#96;&#96;

The &#96;Timer&#96; component is now ready to be used in your React Native app. To do this, open the &#96;App.js&#96; file and import the &#96;Timer&#96; component:

&#96;&#96;&#96;js
import React from &#x27;react&#x27;;
import Timer from &#x27;.&#x2F;Timer&#x27;;
&#96;&#96;&#96;

Now, update the &#96;render()&#96; method to render the &#96;Timer&#96; component:

&#96;&#96;&#96;js
render() {
  return (
    &lt;View&gt;
      &lt;Timer &#x2F;&gt;
    &lt;&#x2F;View&gt;
  );
}
&#96;&#96;&#96;

The &#96;Timer&#96; component is now rendered in your React Native app. Now you can start adding the timer functionality. To do this, you will need to add state to the &#96;Timer&#96; component.

At the top of the &#96;Timer.js&#96; file, define a &#96;state&#96; object and set the &#96;time&#96; property to &#96;0&#96;:

&#96;&#96;&#96;js
state = {
  time: 0,
};
&#96;&#96;&#96;

Next, add the &#96;startTimer()&#96; and &#96;stopTimer()&#96; methods to the &#96;Timer&#96; component. The &#96;startTimer()&#96; method will be responsible for starting the timer and the &#96;stopTimer()&#96; method will be responsible for stopping the timer: 

&#96;&#96;&#96;js
startTimer = () =&gt; {
  &#x2F;&#x2F; Start the timer
};

stopTimer = () =&gt; {
  &#x2F;&#x2F; Stop the timer
};
&#96;&#96;&#96;

To start the timer, you will need to use the [&#96;setInterval()&#96;](https:&#x2F;&#x2F;developer.mozilla.org&#x2F;en-US&#x2F;docs&#x2F;Web&#x2F;API&#x2F;WindowOrWorkerGlobalScope&#x2F;setInterval) method. The &#96;setInterval()&#96; method will call a function at regular intervals.

In the &#96;startTimer()&#96; method, call the &#96;setInterval()&#96; method and pass in a callback function to update the &#96;time&#96; state property:

&#96;&#96;&#96;js
startTimer = () =&gt; {
  this.interval = setInterval(() =&gt; {
    this.setState(state =&gt; ({
      time: state.time + 1,
    }));
  }, 1000);
};
&#96;&#96;&#96;

The &#96;setInterval()&#96; method is called every second and the &#96;time&#96; state property is incremented by &#96;1&#96;.

To stop the timer, you will need to use the [&#96;clearInterval()&#96;](https:&#x2F;&#x2F;developer.mozilla.org&#x2F;en-US&#x2F;docs&#x2F;Web&#x2F;API&#x2F;WindowOrWorkerGlobalScope&#x2F;clearInterval) method. In the &#96;stopTimer()&#96; method, call the &#96;clearInterval()&#96; method and pass in the &#96;interval&#96; variable:

&#96;&#96;&#96;js
stopTimer = () =&gt; {
  clearInterval(this.interval);
};
&#96;&#96;&#96;

Now you can add the timer display to the &#96;render()&#96; method of the &#96;Timer&#96; component. To do this, use the &#96;Text&#96; component to render the &#96;time&#96; state property:

&#96;&#96;&#96;js
render() {
  return (
    &lt;View&gt;
      &lt;Text&gt;{this.state.time}&lt;&#x2F;Text&gt;
    &lt;&#x2F;View&gt;
  );
}
&#96;&#96;&#96;

The timer display is now rendered in the &#96;Timer&#96; component. Now you can add the start and stop buttons. To do this, create two new &#96;TouchableOpacity&#96; components and add the &#96;onPress&#96; props to call the &#96;startTimer()&#96; and &#96;stopTimer()&#96; methods:

&#96;&#96;&#96;js
&lt;TouchableOpacity onPress={this.startTimer}&gt;
  &lt;Text&gt;Start&lt;&#x2F;Text&gt;
&lt;&#x2F;TouchableOpacity&gt;

&lt;TouchableOpacity onPress={this.stopTimer}&gt;
  &lt;Text&gt;Stop&lt;&#x2F;Text&gt;
&lt;&#x2F;TouchableOpacity&gt;
&#96;&#96;&#96;

The &#96;Timer&#96; component is now complete. When you run the React Native app, you should see the timer display and the start and stop buttons.

## Conclusion

In this tutorial, you learned how to use React Native Timer in your React Native app. You learned how to set up the React Native environment, create a &#96;Timer&#96; component, and add the timer functionality. 

You now have the skills to create a timer app in React Native. Try experimenting with different time intervals and see what you can create!

How To Use React Native Timer (Code Examples)

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