I am working on a imageSlider using Carousel imported from library: "react-native-banner-carousel"
I am trying to fetch the images which are stored locally inside a folder components. I am creating an array if images and then trying to render them through Carousel.
I am certainly getting an error like: "json value '2' of type nsnumber cannot be converted to nsstring"
ImageSlider code:
const BannerWidth = Dimensions.get('window').width;
const BannerHeight = 260;
const images = [
require("./abc.jpg"),
require("./xyz.jpg")
];
export default class ImageSlider extends React.Component {
renderPage(image, index) {
return (
<View key={index}>
<Image style={{ width: BannerWidth, height: BannerHeight }} source={{uri:image}} />
</View>
);
}
render() {
return (
<View style={styles.container}>
<Carousel
autoplay
autoplayTimeout={5000}
loop
index={0}
pageSize={BannerWidth}
>
{images.map((image, index) => this.renderPage(image, index))}
</Carousel>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
backgroundColor: '#fff',
justifyContent: 'center'
},
});
As a result I should be able to render all the images displayed inside the images array. But I am getting this error.
Where am I getting wrong here?
Your issue is here:
const images = [
require("./abc.jpg"),
require("./xyz.jpg")
];
The require does not return the URL of the image but the internal index of the media. Which in your case I assume is 2, and the interface for the image is expecting a string.
Try this:
<Image style={{ width: BannerWidth, height: BannerHeight }} source={image} />
For anyone that is searching this error for whom the top answer didn't work: I received this error in React(Native) and wrote marginTop: '5'. With Parenthesis. It should be marginTop: 5
Wrong:
marginTop: '5'
Correct:
marginTop: 5
Related
I'm trying to make a layout so that the later parts of the view are only reachable by scrolling.
Currently I'm using Dimensions to generate Views with the correct height. Is there a better way of doing so? My current solution doesn't seem too correct.
export default function MyApp() {
const height = Dimensions.get('window').height;
return (
<View style={styles.container}>
<ScrollView>
<View style={{backgroundColor: 'green', height:height}}/>
<View style={{backgroundColor: 'red', height:40}}/>
</ScrollView>
</View>
);
}
const styles = StyleSheet.create({
container:{
backgroundColor: 'white',
flex: 1
}
});
You can use VirtualizedList component, for example as
<VirtualizedList
data={['body']}
renderItem={({ item }) => (
<View style={styles.screen}>
{/* Put more content for body */}
</View>
)}
keyExtractor={(item, index) => index.toString()}
getItemCount={() => {
return 1;
}}
getItem={(data, index) => {
return data[index];
}}>
</VirtualizedList>
Your solution work, but not good and it have downside, when you change your phone orientation to landscape there will be bug. I dont like using Dimensions in my code unless there is no other way or use Dimensions addEventListener to listen window size and update component whenever window size change. I will suggest you a better way.
First, create a component called LayoutSizeAwareView, after this view rendered, we will catch it size from onLayout props and use them to render it children.
const LayoutSizeAwareView = (props) => {
const [size, setSize] = React.useState({width: 0, height: 0});
return (
<View
...props,
onLayout={(e) => {
setSize({
width: e.nativeEvent.layout.width,
height: e.nativeEvent.layout.height,
})
props.onLayout(e)
}}
>
{props.children(size)}
</View>
)
}
And then, in your case, use it like this
export default function MyApp() {
return (
<LayoutSizeAwareView style={styles.container}>
{({width, height}) => {
return (
<ScrollView>
<View style={{backgroundColor: 'green', height: height}}/>
<View style={{backgroundColor: 'red', height: 40}}/>
</ScrollView>
)
}}
</View>
);
}
const styles = StyleSheet.create({
container:{
backgroundColor: 'white',
flex: 1
}
});
This way your code look even cooler, there will be some typo in my code since I dont have IDE here, but you might get the idea.
Background:
I've designed a custom footer for my app in React Native, I've set some images to act as icons. I'm trying to have them redirect to other pages of the app upon touch.
What I have tried
I've been trying to use the same images nested within TouchableOpacity components to have them redirect to other pages using react navigation.
This is my code:
export class Footer extends React.Component {
render (){
return (
<View style = { styles.footStyle } >
<TouchableOpacity onPress={ () => navigation.push('Home')} >
<Image
style = { styles.iconStyle }
source = {require('./img/home.png')}/>
</TouchableOpacity>
<TouchableOpacity onPress={ () => navigation.push('Favoritos')} >
<Image
style = { styles.iconStyle }
source = {require('./img/heart.png')}/>
</TouchableOpacity>
<TouchableOpacity onPress={ () => navigation.push('Search')} >
<Image
style = { styles.iconStyle }
source = {require('./img/search.png')}/>
</TouchableOpacity>
<TouchableOpacity onPress={ () => navigation.push('Notifications')} >
<Image
style = { styles.iconStyle }
source = {require('./img/bell.png')}/>
</TouchableOpacity>
<TouchableOpacity onPress={ () => navigation.push('Help')} >
<Image
style = { styles.iconStyle }
source = {require('./img/circle.png')}/>
</TouchableOpacity>
</View>
)
}
}
const styles = StyleSheet.create({
footStyle: {
paddingBottom: 0,
paddingRight: 10,
backgroundColor: '#ffffff',
flex: 0.4,
flexDirection: 'row',
borderTopWidth: 1,
borderTopColor: '#000000'
},
iconStyle: {
flex: 0.2,
height: undefined,
width: undefined
}
})
Problem
When I try and run the app in expo, the images are not rendering at all. I get my blank footer without any content. I've tried touching the footer to see if the images weren't rendering but the "button" actually worked, that didn't work.
Question
How exactly can I nest an image within a TouchableOpacity component? Is it even possible to use this method with React Navigation?
Thanks a lot!
For an Image component to work you should provide a height and width in style.
Here you are setting it as undefined
Try something like
iconStyle: {
flex: 0.2,
height: 100,
width: 100
}
Also on the navigation, you will have to pass the navigation prop to the Footer. As its a class you should access it as this.props.navigation.navigate()
As your code for integrating the Footer is not here, its hard to comment on how to pass the prop to the footer.
I want to show 6 options per row instead of showing only one option per row.
I'm still new in react-native
Here is the code :
import React from 'react';
import {fromJS} from 'immutable';
import {ScrollView, StyleSheet, TouchableOpacity} from 'react-native';
import {Text} from 'src/components';
import Option from './OptionVariable';
import {checkOption} from 'src/modules/product/helper';
import {margin} from 'src/components/config/spacing';
class AttributeVariable extends React.Component {
onSelectOption = (option) => {
const {onSelectAttribute, attribute} = this.props;
onSelectAttribute(attribute.get('id'), attribute.get('name'), option.get('option'));
};
render() {
const {attribute, meta_data, variations} = this.props;
// Attribute selected
const attributeSelected = meta_data.find(attr => attr.get('id') === attribute.get('id') && attr.get('name') === attribute.get('name'));
return (
<>
<Text>
{attribute.get('name')}: <Text colorSecondary>{attributeSelected ? attributeSelected.get('option') : ''}</Text>
</Text>
<ScrollView
style={styles.attribute}
vertical
showsHorizontalScrollIndicator={false}>
{attribute.get('options').map(option => {
const disabled = meta_data.size === 0 ? false : !checkOption(variations, meta_data, fromJS({
id: attribute.get('id'),
name: attribute.get('name'),
option: option.get('option'),
}));
return (
<TouchableOpacity
activeOpacity={disabled ? 1 : 0}
key={option}
onPress={() => disabled ? {} : this.onSelectOption(option)}
>
<Option
type={attribute.get('type')}
selected={attributeSelected && option.get('option') === attributeSelected.get('option')}
disabled={disabled}
option={option}
/>
</TouchableOpacity>
)
})}
</ScrollView>
</>
);
}
}
const styles = StyleSheet.create({
attribute: {
marginTop: margin.small,
},
});
export default AttributeVariable;
Here is how it looks :
I hope everything is clear to you.
Sorry for my bad english it's not my main language....
Thanks in advance for any help.
you can say in your attribute style:
attribute: {
marginTop: margin.small,
flexDirection: 'row'
},
so it should align in rows instead of columns
That should help you to learn more about styling components in react native: https://facebook.github.io/react-native/docs/flexbox
Try using the Flatlist (instead of ScrollView) component passing the horizontal={true} props.
Like this:
FlatList
horizontal={true}
data={attribute.option}
renderItem={({ item }) => "Pass your component"}
keyExtractor={item => item.id}
/>
UPDATE 2 :
I used View instead of ScrollView with the following styles and it worked just fine..
<View style={[styles.container, ]}
horizontal
style={{AlignContent: 'flex-start', flexDirection: 'row', alignItems: 'flex-start',}}
style={styles.attribute}
showsHorizontalScrollIndicator={false}>
UPDATE 1 :
I solved the problem using this :
container: {
marginTop: margin.small,
flexDirection: 'row-reverse',
position: 'relative',
width: 'auto',
alignSelf: 'stretch',
maxWidth: 29,
height: 29,
marginBottom: margin.big,
borderRadius: borderRadius.base,
borderWidth: 1,
},
I changed the size of option so all of them appear on the same row (not exactly what I want but it works)
If anyone have a better answer please share.
I have a list of chat messages in my app to which new items are added to the bottom. I used some code from another SO question to make the FlatList stick to the bottom when new items are added, as below
<FlatList
data={messages}
renderItem={({item}) => <ChatMessage message={item}></ChatMessage>}
keyExtractor={(item, index) => index.toString()}
initialNumToRender={messages.length}
initialScrollIndex={messages.length-1}
ref={ref => this.flatList = ref}
onContentSizeChange={(contentWidth, contentHeight)=>{
this.flatList.scrollToEnd();
}}
/>
The problem is that when the initial list renders (only 35 items, hardcoded in an array for now) it seems to render just a few items, then scroll down a bit, then render a few more, then scroll down a bit until it finally completes the rendering and sticks to the bottom. It's choppy and slow, despite adding initialNumToRender={messages.length} and rendering an incredibly simple node for each result.
Ideally I guess I need to wait for it to fully render before displaying anything to the user but (A) they'd have to wait a couple of seconds to start using the chat room and (B) I don't think that's how Flatlist works, I assume the elements have to be viewable before it is rendered.
Is there just a better way to do this? (Testing on Android by the way)
EDIT: Adding ChatMessage component for completeness
// Chat Message
import React, { Component } from 'react'
import {
StyleSheet,
ImageBackground,
Text,
View
} from 'react-native'
class ChatMessage extends Component {
constructor(props) {
super(props)
this.state = { }
}
render() {
return (
<View style={styles.chatMessage}>
<View style={styles.chatMessage_layout}>
<View style={styles.chatMessage_pic}>
<View style={styles.chatMessage_pic_image}>
<ImageBackground
source={require('./assets/images/profile-pics/example-profilr.png')}
style={styles.chatMessage_pic_image_background}
imageStyle={{ borderRadius: 40/2 }}
resizeMode="cover"
>
</ImageBackground>
</View>
</View>
<View style={styles.chatMessage_details}>
<View style={styles.chatMessage_name}>
<Text style={styles.chatMessage_name_text}>
{this.props.message.name}
<Text style={styles.chatMessage_name_time}> 24h</Text>
</Text>
</View>
<View style={styles.chatMessage_message}>
<Text style={styles.chatMessage_message_text}>{this.props.message.text}</Text>
</View>
</View>
</View>
</View>
)
}
}
export default ChatMessage;
const styles = StyleSheet.create({
chatMessage: {
paddingVertical: 10,
paddingHorizontal: 24
},
chatMessage_layout: {
flexDirection: 'row'
},
chatMessage_pic: {
width: 40,
height: 40,
marginRight: 12
},
chatMessage_pic_image: {
width: 40,
height: 40
},
chatMessage_pic_image_background: {
width: 40,
height: 40
},
chatMessage_details: {
flex: 1
},
chatMessage_name_text: {
color: '#FFF',
fontSize: 14,
fontWeight: 'bold'
},
chatMessage_name_time: {
fontSize: 11,
color: 'rgba(255,255,255,0.6)'
},
chatMessage_message: {
flexDirection: 'row',
alignItems: 'center'
},
chatMessage_message_text: {
color: '#FFF',
fontSize: 12
}
})
If you have less number of items and want to render all items at once then you should use ScrollView as mentioned in the docs
ScrollView: Renders all elements at once, but slow if there are large number of elements.
FlatList: Renders items in a lazy mode, when they are about to appear and removes them when they leave the visible display to save memory that makes it usable for performance on large lists.
For Flatlist optimization you need to use PureComponent whenever you render the child so that it only shallow compares the props.
Also in the keyExtractor use a unique id for your item and do not depend upon the index, since when the item updates the index is not reliable and may change
I want to directly update the value of a component due to performance reasons.
render(){
<View>
<Text style={styles.welcome} ref={component => this._text = component}>
Some Text
</Text>
<TouchableHighlight underlayColor='#88D4F5'
style={styles.button}>
<View>
<Text style={styles.buttonText}
onPress={this.useNativePropsToUpdate.bind(this)}>
Iam the Child
</Text>
</View>
</TouchableHighlight>
</View>
}
This is the method I use to update the text component. I dont know if I am setting the right attribute/ how to figure out which attribute to set:
useNativePropsToUpdate(){
this._text.setNativeProps({text: 'Updated using native props'});
}
Essentially trying to follow the same approach from this example:
https://rnplay.org/plays/pOI9bA
Edit:
When I attempt to explicitly assign the updated value:
this._text.props.children = "updated";
( I know this this the proper way of doing things in RN ). I get the error "Cannot assign to read only property 'children' of object'#'"
So maybe this is why it cant be updated in RN for some reason ?
Instead of attempting to change the content of <Text> component. I just replaced with <TextInput editable={false} defaultValue={this.state.initValue} /> and kept the rest of the code the same. If anyone know how you can change the value of <Text> using setNativeProps OR other method of direct manipulations. Post the answer and ill review and accept.
The text tag doesn't have a text prop, so
this._text.setNativeProps({ text: 'XXXX' })
doesn't work.
But the text tag has a style prop, so
this._text.setNativeProps({ style: { color: 'red' } })
works.
We can't use setNativeProps on the Text component, instead, we can workaround and achieve the same result by using TextInput in place of Text.
By putting pointerEvent='none' on the enclosing View we are disabling click and hence we can't edit the TextInput (You can also set editable={false} in TextInput to disbale editing)
Demo - Timer (Count changes after every 1 second)
import React, {Component} from 'react';
import {TextInput, StyleSheet, View} from 'react-native';
class Demo extends Component {
componentDidMount() {
let count = 0;
setInterval(() => {
count++;
if (this.ref) {
this.ref.setNativeProps({text: count.toString()});
}
}, 1000);
}
render() {
return (
<View style={styles.container} pointerEvents={'none'}>
<TextInput
ref={ref => (this.ref = ref)}
defaultValue={'0'}
// editable={false}
style={styles.textInput}
/>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 0.7,
justifyContent: 'center',
alignItems: 'center',
},
textInput: {
fontSize: 60,
width: '50%',
borderColor: 'grey',
borderWidth: 1,
aspectRatio: 1,
borderRadius: 8,
padding: 5,
textAlign: 'center',
},
});
export default Demo;
As setNativeProps not solving the purpose to alter the content of <Text />, I have used below approach and is working good. Create Simple React Component like below...
var Txt = React.createClass({
getInitialState:function(){
return {text:this.props.children};
},setText:function(txt){
this.setState({text:txt});
}
,
render:function(){
return <Text {...this.props}>{this.state.text}</Text>
}
});