React Native: Different styles applied on orientation change

If using Hooks. You can refer to this solution: https://stackoverflow.com/a/61838183/5648340

The orientation of apps from portrait to landscape and vice versa is a task that sounds easy but may be tricky in react native when the view has to be changed when orientation changes. In other words, having different views defined for the two orientations can be achieved by considering these two steps.

Import Dimensions from React Native

import { Dimensions } from 'react-native';

To identify the current orientation and render the view accordingly

/**
 * Returns true if the screen is in portrait mode
 */
const isPortrait = () => {
    const dim = Dimensions.get('screen');
    return dim.height >= dim.width;
};
 
/**
 * Returns true of the screen is in landscape mode
 */
const isLandscape = () => {
    const dim = Dimensions.get('screen');
    return dim.width >= dim.height;
};

To know when orientation changes to change view accordingly

// Event Listener for orientation changes
    Dimensions.addEventListener('change', () => {
        this.setState({
            orientation: Platform.isPortrait() ? 'portrait' : 'landscape'
        });
    });

Assembling all pieces

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

export default class App extends React.Component {
  constructor() {
    super();

    /**
    * Returns true if the screen is in portrait mode
    */
    const isPortrait = () => {
      const dim = Dimensions.get('screen');
      return dim.height >= dim.width;
    };

    this.state = {
      orientation: isPortrait() ? 'portrait' : 'landscape'
    };

    // Event Listener for orientation changes
    Dimensions.addEventListener('change', () => {
      this.setState({
        orientation: isPortrait() ? 'portrait' : 'landscape'
      });
    });

  }

  render() {
    if (this.state.orientation === 'portrait') {
      return (
          //Render View to be displayed in portrait mode
       );
    }
    else {
      return (
        //Render View to be displayed in landscape mode
      );
    }

  }
}

As the event defined for looking out the orientation change uses this command ‘this.setState()’, this method automatically again calls for ‘render()’ so we don’t have to worry about rendering it again, it’s all taken care of.

Here's @Mridul Tripathi's answer as a reusable hook:

// useOrientation.tsx
import {useEffect, useState} from 'react';
import {Dimensions} from 'react-native';

/**
 * Returns true if the screen is in portrait mode
 */
const isPortrait = () => {
  const dim = Dimensions.get('screen');
  return dim.height >= dim.width;
};

/**
 * A React Hook which updates when the orientation changes
 * @returns whether the user is in 'PORTRAIT' or 'LANDSCAPE'
 */
export function useOrientation(): 'PORTRAIT' | 'LANDSCAPE' {
  // State to hold the connection status
  const [orientation, setOrientation] = useState<'PORTRAIT' | 'LANDSCAPE'>(
    isPortrait() ? 'PORTRAIT' : 'LANDSCAPE',
  );

  useEffect(() => {
    const callback = () => setOrientation(isPortrait() ? 'PORTRAIT' : 'LANDSCAPE');

    Dimensions.addEventListener('change', callback);

    return () => {
      Dimensions.removeEventListener('change', callback);
    };
  }, []);

  return orientation;
}

You can then consume it using:

import {useOrientation} from './useOrientation';

export const MyScreen = () => {
    const orientation = useOrientation();

    return (
        <View style={{color: orientation === 'PORTRAIT' ? 'red' : 'blue'}} />
    );
}

React Native: Different styles applied on orientation change

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