How to handle responsive layout in React Native - react-native

I'm using the react-native-dimension library for making my UI responsive as follows:
const{width,height} = Dimensions.get('window');
and in my style.js file :
imageBackgroundLandscape:{
width:height,
height:width
},
imageBackgroundPortrait:{
width:width,
height:height
}
The problem is that when I rotate the screen, the width and height variables have got previous values!
For example in the portrait mode my variables are:
width : 800
height: 1280
and when I rotate the screen my variables are:
width : 800 // previous value
height: 1280 // previous value
In addition, I use the react-native-orientation to determine the mode of the screen.
I want to know how can I change the values of them (width, height) automatically when I rotate the device, or are there any other libraries for this?
Thanks in advance.

I usually handle the height, width confusion with the following code:
//Dimensions.js
import {Dimensions} from 'react-native';
const {height, width} = Dimensions.get('window');
const actualDimensions = {
height: (height<width) ? width : height,
width: (width>height) ? height : width
};
export default actualDimensions;
Instead of requiring the height and width from Dimensions, use the actualDimensions and for managing the orientation gracefully you should give a try to this library as well.
The Dimensions are loaded before the JS bundle gets loaded into the app so it is recommended to fetch the height, width dynamically for every render
You can read this here

I usually used Flexbox to arrange the layout for my components. It helps them to be responsive. Maybe you could give a try too.
Layout with Flexbox

You can use these steps to make your UI responsive.
1: use percentage whenever it's possible
2: use the power of flexbox to make your UI grow and shrink
3: use Dimension API

Actually, you do right but half of the task. you got the width and height from Dimensions and it is right, but how react-native understand your orientation changes?
First, your code should understand the change of orientation, then you set a call-back function to change the state of your application for implementing new width and height.
Awfully, I don't know the react-native can understand a change of orientation with its built-in functions or not. So I'm using this library to understand orientation changes and then I use setState to re-render the codes.
Absolutely, I put the width and height inside state of the component.
If you wanna lock the orientation change, use this library.

Firstly:
You are facing that issue is because you forgot to call const{width,height}
= Dimensions.get('window'); again when the orientation has changed.
In order to get the latest value of width and height after the orientation change you would have to call the Dimensions.get('window') function again and get width and height from it's output.
Secondly:
Instead of using multiple libraries, you can just use one library(react-native-styleman), that lets you handle this type of stuff very easily:
Here is how the code would look like using react-native-styleman.
import { withStyles } from 'react-native-styleman';
const styles = () => ({
container: {
// your common styles here for container node.
flex: 1,
// lets write a media query to change background color automatically based on the device's orientation
'#media': [
{
orientation: 'landscape', // for landscape
styles: { // apply following styles
// these styles would be applied when the device is in landscape
// mode.
backgroundColor: 'green'
//.... more landscape related styles here...
}
},
{
orientation: 'portrait', // for portrait
styles: { // apply folllowing styles
// these styles would be applied when the device is in portrait
// mode.
backgroundColor: 'red'
//.... more protrait related styles here...
}
}
]
}
});
let MainComponent = ({ styles })=>(
<View style={styles.container}>
<Text> Hello World </Text>
</View>
);
// now, lets wire up things together.
MainComponent = withStyles(styles)(MainComponent);
export {
MainComponent
};

I am using react-native-responsive-screen. it is working also with orientation change
USAGE
import {
widthPercentageToDP as wp,
heightPercentageToDP as hp,
listenOrientationChange as lor,
removeOrientationListener as rol
} from 'react-native-responsive-screen';
class Login extends Component {
componentDidMount() {
lor(this);
}
componentWillUnmount() {
rol();
}
render() {
const styles = StyleSheet.create({
container: { flex: 1 },
textWrapper: {
height: hp('70%'),
width: wp('80%')
},
myText: { fontSize: hp('5%') }
});
return (
<View style={styles.container}>
<View style={styles.textWrapper}>
<Text style={styles.myText}>Login</Text>
</View>
</View>
);
}
}
export default Login;

Related

Adjust the scrollview height dynamically at runtime

I am developing a react-native project.
I have a ScrollView in MyComponent, the content of ScrollView consists of :
a MySubComponent,
a Text
a Image component
All the content/data of above components have dynamic length or height. So, I would like adjust the content height of my ScrollView on the fly at runtime.
To achieve that my plan is to disable automaticallyAdjustContentInsets of the ScrollView as you can see from my below code snippet. Then, have a state variable to hold the latest value of contentInsetBottom. But I am not sure how can I calculate the height of child components so that I can call setContentInsetBottom(totalHeight) to update the content height of my ScrollView .
(I am pretty sure my plan will work if I know how to calculate the height of each child component of my ScrollView.)
Anyone can guide me a bit?
const MyComponent = ({myText, image}) => {
// I have a state of the contentInsetBottom for the ScrollView
const [contentInsetBottom, setContentInsetBottom] = useState(0);
// how can I get the height of each children component, sum them up & call setContentInsetBottom(totalHeight) here ?
return (
<ScrollView
automaticallyAdjustContentInsets={false}
contentInset={{top: 0, bottom: contentInsetBottom}}
style={styles.scrollView}
contentContainerStyle={styles.contentContainer}>
<MySubComponent />
<Text>{myText}</Text>
<Image source={{uri: image?.uri}}>
</ScrollView>)
}
Wrap all content inside the <ScrollView> in a <View>. Then use onLayout to get the height of that parent View.
const handleScrollContentLayout = (e) => {
const { height } = e.nativeEvent.layout
setScrollLayoutHeight(height)
}
...
<View onLayout={handleScrollContentLayout}>
{ /* scrollView content... */ }
</View>
Then you can use the scrollLayoutHeight as per your needs to set the height at runtime.

How to make the icon of a bottom tab navigator fit inside the tab bar?

I'm using a bottomTabNavigator in my React Native app. I'm using an component as an icon. Is is possible to make it fit inside the tab (with padding) without explicitly defining a size?
If not, is there some constant in which I can get the tab bar height?
This is what I'm getting:
and this is my tabBarIcon code:
/**
*
*/
import React from 'react';
import {
Image,
Text,
StyleSheet,
} from 'react-native';
export default class TabMenuIcon extends React.Component {
static SCREENS = {
SOCIAL: "s",
CALCULATION: "c",
CONFIGURE: "d"
};
render() {
const { focused, tintColor, size, which } = this.props;
switch(which) {
case TabMenuIcon.SCREENS.SOCIAL:
return <Image source={require('../assets/icons/tabsocial.png')} style={style.img} />
break;
case TabMenuIcon.SCREENS.CALCULATION:
return <Image source={require('../assets/icons/tabcalculations.png')} style={style.img} />
break;
case TabMenuIcon.SCREENS.CONFIGURE:
return <Image source={require('../assets/icons/tabconfigure.png')} style={style.img} />
break;
default:
return <Text>t</Text>
}
}
}
const style = StyleSheet.create({
img: {
padding:6, // Does nothing??
margin: 4, // Does nothing??
}
});
What im saying is dont hardcode the image height, rather you can check for the height of image in your simulator, and suppose you give height and width to be 10.
It fits perfectly suppose. Then to ensure that just giving 10 doesnt break my image in other phones which has different screen resolution you can do ,
height = (10/640) * deviceHeight
width = (10/360) * deviceWidth.
here im assuminb your phone height and width are 640 and 360 respectively.
you can get device height and width by :
import {Dimensions} from 'react-native;
deviceWidth = Dimensions.get('window').width,
deviceHeight= Dimensions.get('window').height
hope it clears

React native navigation newbie: Fullscreen width on a showInAppNotification?

I'm using react-native-navigation to show error notification dropdowns via 'showInAppNotification'.
I've tried to style the dropdown box with:
{
backgroundColor: colorRed,
flex: 1,
alignSelf: 'stretch',
}
I can't get the box to obey that flex call. It stays as the width of the text inside the notification.
That is, what I get is this:
And what I want is this:
(The second is achieved by setting a hard width of 999, but that isn't a satisfactory solution)
So, from my limited understanding of React Native's stylesheet logic, I assumed I had a parent element with a fixed width above the notification. Except I don't. It's called directly (well, unless I'm missing some sort of injected showInAppNotification component) into my Provider HOC, which looks like this:
<Provider store={store}>
<ErrorBoundary>
{children}
</ErrorBoundary>
</Provider>
To confirm the ErrorBoundary was fullscreen width, I threw a backgroundColor: green on the error boundary. It came back as the expected width, like this:
Any thoughts on what could be going on? As mentioned I'm new to react native & it's possible I'm missing something obvious w/regards to flex logic, but I suspect it's a react-native-navigator notification issue I'm hoping others have run into. Any thoughts appreciated.
Instead of giving your width a hard-coded value you can import react native's Dimensions class into your component and use it in order to set the width.
So, your code can look something like this:
import { ...., Dimensions } from 'react-native';
const { width } = Dimensions.get('window');
const styles = {
notification : {
backgroundColor: colorRed,
width,
alignSelf: 'stretch'
}
}

React Native how to do min/max widths

I want to style a component in my interface. The component must have a width of at least 200, but I want to let it grow with screen width to up to 600. But, sometimes people use tablets or huge phones. And I don't want the component to be able to grow with the screen forever. I want it to have a maximum width of 600.
And I know maxWidth is a thing that is, at least for now, not a part of the flexbox implementation in React Native... so, is there a reasonable way to do this today?
You can use the maxWidth, maxHeight, minWidth, minHeight layout properties supported by React Native.
Document here React Native layout props.
Example:
StyleSheet.create({
container: {
maxWidth: '80%', // <-- Max width is 80%
minHeight: 20, // <-- Min height is 20
},
});
There is no such thing as "maxWidth" in React Native. You may want to style your component at run-time. Try playing with Dimensions. You can get screen width and screen height of the device and adjust width of your component accordingly.
You can define two different style objects.
For full-width component on a device having width less than 600.
componentStyle_1: {
flex: 1
}
For 600 width on a device having width greater than 600
componentStyle_2: {
width: 600
}
You can check the device width runtime.
var {height, width} = Dimensions.get('window');
if(width>600){
//load componentStyle_1
}
else{
//load componentStyle_2
}
Best way to get accurate results is to play with your code. Good luck!
Refer: https://facebook.github.io/react-native/docs/dimensions.html#content
Simple. Just use maxWidth in your styles.
In a practical manner, this is how you would use it:
import { StyleSheet, Text, View, Dimensions, (+ anything else you need such as Platform to target specific device widths } from "react-native";
// plus whatever other imports you need for your project...
In a class component, you would create a state called whatever, let's say deviceWidth. Then inside the component you would use:
constructor(props) {
super(props);
this.state = {
deviceWidth: 375, // Put in any default size here or just "null"
// plus any other state keys you need in your project
}
componentDidMount() {
const currentWidth = Dimensions.get("screen").width;
this.setState({deviceWidth: currentWidth});
}
In a functional component you would import:
import React, { useEffect, useState } from "react";
Then inside your functional component you would add in:
const [currentWidth, setCurrentWidth] = useState(null //or add in a default width);
useEffect(() => {
const currentWidth = Dimensions.get("screen").width;
setCurrentWidth({deviceWidth: currentWidth});
}, []);
You could also use:
const deviceDisplay = Dimensions.get("window");
const deviceHeight = deviceDisplay.height;
const deviceWidth = deviceDisplay.width;
..if you wanted to find the height as well. On Android, "window" gets you the full screen height including the upper bar while "screen" gets you height without upper bar. Window and screen on iOS are the same.
Then using inline styles so that you have access to the state, set the width & maxWidth:
<View style={[styles.wrapper, { width: this.state.deviceWidth, maxWidth: 400, // or whatever you want here. } ]} >
Any width settings in a wrapper style found in your StyleSheet object will be over-ridden by the inline style, just like in CSS.
Alternatively if you don't have any other styles declared in your StyleSheet object, just use:
<View style={{ width: this.state.deviceWidth, maxWidth: 400 }} >
Or in a functional component, that would be:
<View style={{ width: deviceWidth, maxWidth: 400 }} >

Getting measurements of UI elements in React Native

Is there a way to get pixel measurements of native elements in React Native? For example:
Right now I'm hardcoding how much padding needs to exist so that the content isn't covered by the nav bar:
const styles = StyleSheet.create({
container: {
paddingTop: 64
}
});
IMO this is not acceptable. Is there some way to measure these elements?
Yes, you can use the onLayout event:
getInitialState() {
return { }
}
<View onLayout={(event) => this.measureView(event)}>
measureView(event) {
console.log('event properties: ', event);
this.setState({
x: event.nativeEvent.layout.x,
y: event.nativeEvent.layout.y,
width: event.nativeEvent.layout.width,
height: event.nativeEvent.layout.height
})
}
As far as calling these on Native elements, I have not tried, but possibly passing the function into the component may do it, or wrapping the native element in a view and calling the function on the outer view.