I'm really new to React Native and I'm wondering how can I hide/show a component.
Here's my test case:
<TextInput
onFocus={this.showCancel()}
onChangeText={(text) => this.doSearch({input: text})} />
<TouchableHighlight
onPress={this.hideCancel()}>
<View>
<Text style={styles.cancelButtonText}>Cancel</Text>
</View>
</TouchableHighlight>
I have a TextInput
component, what I want is to show the TouchableHighlight
when the input gets the focus, then hide the TouchableHighlight
when the user press the cancel button.
I don´t know how to "access" the TouchableHighlight
component in order to hide/show it inside of my functions showCancel/hideCancel
.
Also, how can I hide the button from the very beginning?
I would do something like this:
var myComponent = React.createComponent({
getInitialState: function () {
return {
showCancel: false,
};
},
toggleCancel: function () {
this.setState({
showCancel: !this.state.showCancel
});
}
_renderCancel: function () {
if (this.state.showCancel) {
return (
<TouchableHighlight
onPress={this.toggleCancel()}>
<View>
<Text style={styles.cancelButtonText}>Cancel</Text>
</View>
</TouchableHighlight>
);
} else {
return null;
}
},
render: function () {
return (
<TextInput
onFocus={this.toggleCancel()}
onChangeText={(text) => this.doSearch({input: text})} />
{this._renderCancel()}
);
}
});
In your render function:
{ this.state.showTheThing &&
<TextInput/>
}
Then just do:
this.setState({showTheThing: true}) // to show it
this.setState({showTheThing: false}) // to hide it
In react or react native the way component hide/show or add/remove does not work like in android or iOS. Most of us think there would be the similar strategy like
View.hide = true or parentView.addSubView(childView)
But the way react native work is completely different. The only way to achieve this kind of functionality is to include your component in your DOM or remove from DOM.
Here in this example I am going set the visibility of text view based on the button click.
The idea behind this task is the create a state variable called state having the initial value set to false when the button click event happens then it value toggles. Now we will use this state variable during the creation of component.
import renderIf from './renderIf'
class FetchSample extends Component {
constructor(){
super();
this.state ={
status:false
}
}
toggleStatus(){
this.setState({
status:!this.state.status
});
console.log('toggle button handler: '+ this.state.status);
}
render() {
return (
<View style={styles.container}>
{renderIf(this.state.status)(
<Text style={styles.welcome}>
I am dynamic text View
</Text>
)}
<TouchableHighlight onPress={()=>this.toggleStatus()}>
<Text>
touchme
</Text>
</TouchableHighlight>
</View>
);
}
}
the only one thing to notice in this snippet is renderIf
which is actually a function which will return the component passed to it based on the boolean value passed to it.
renderIf(predicate)(element)
renderif.js
'use strict';
const isFunction = input => typeof input === 'function';
export default predicate => elemOrThunk =>
predicate ? (isFunction(elemOrThunk) ? elemOrThunk() : elemOrThunk) : null;
in render() you can conditionally show the JSX or return null as in:
render(){
return({yourCondition ? <yourComponent /> : null});
}
I needed to switch between two images. With conditional switching between them there was 5sec delay with no image displayed.
I'm using approach from downvoted amos answer. Posting as new answer because it's hard to put code into comment with proper formatting.
Render function:
<View style={styles.logoWrapper}>
<Image
style={[styles.logo, loading ? styles.hidden : {}]}
source={require('./logo.png')} />
<Image
style={[styles.logo, loading ? {} : styles.hidden]}
source={require('./logo_spin.gif')} />
</View>
Styles:
var styles = StyleSheet.create({
logo: {
width: 200,
height: 200,
},
hidden: {
width: 0,
height: 0,
},
});
Most of the time i'm doing something like this :
class MyComponent extends React.Component {
constructor(props) {
super(props);
this.state = {isHidden: false};
this.onPress = this.onPress.bind(this);
}
onPress() {
this.setState({isHidden: !this.state.isHidden})
}
render() {
return (
<View style={styles.myStyle}>
{this.state.isHidden ? <ToHideAndShowComponent/> : null}
<Button title={this.state.isHidden ? "SHOW" : "HIDE"} onPress={this.onPress} />
</View>
);
}
}
If you're kind of new to programming, this line must be strange to you :
{this.state.isHidden ? <ToHideAndShowComponent/> : null}
This line is equivalent to
if (this.state.isHidden)
{
return ( <ToHideAndShowComponent/> );
}
else
{
return null;
}
But you can't write an if/else condition in JSX content (e.g. the return() part of a render function) so you'll have to use this notation.
This little trick can be very useful in many cases and I suggest you to use it in your developments because you can quickly check a condition.
Regards,
React Native's layout has the display
property support, similar to CSS.
Possible values: none
and flex
(default).
https://facebook.github.io/react-native/docs/layout-props#display
<View style={{display: 'none'}}> </View>
Hide And Show parent view of Activity Indicator
constructor(props) {
super(props)
this.state = {
isHidden: false
}
}
Hide and Show as Follow
{
this.state.isHidden ? <View style={style.activityContainer} hide={false}><ActivityIndicator size="small" color="#00ff00" animating={true}/></View> : null
}
Full reference
render() {
return (
<View style={style.mainViewStyle}>
<View style={style.signinStyle}>
<TextField placeholder='First Name' keyboardType='default' onChangeFirstName={(text) => this.setState({firstName: text.text})}/>
<TextField placeholder='Last Name' keyboardType='default' onChangeFirstName={(text) => this.setState({lastName: text.text})}/>
<TextField placeholder='Email' keyboardType='email-address' onChangeFirstName={(text) => this.setState({email: text.text})}/>
<TextField placeholder='Phone Number' keyboardType='phone-pad' onChangeFirstName={(text) => this.setState({phone: text.text})}/>
<TextField placeholder='Password' secureTextEntry={true} keyboardType='default' onChangeFirstName={(text) => this.setState({password: text.text})}/>
<Button style={AppStyleSheet.buttonStyle} title='Sign up' onPress={() => this.onSignupPress()} color='red' backgroundColor='black'/>
</View>
{
this.state.isHidden ? <View style={style.activityContainer}><ActivityIndicator size="small" color="#00ff00" animating={true}/></View> : null
}
</View>
);
}
On Button presss set state as follow
onSignupPress() {
this.setState({isHidden: true})
}
When you need to hide
this.setState({isHidden: false})
just use
style={ width:0, height:0 } // to hide
I had the same issue where I would want to show / hide Views, but I really didn't want the UI jumping around when things were added/removed or necessarily to deal with re-rendering.
I wrote a simple Component to deal with it for me. Animated by default, but easy to toggle. I put it on GitHub and NPM with a readme, but all the code is below.
npm install --save react-native-hideable-view
import React, { Component, PropTypes } from 'react';
import { Animated } from 'react-native';
class HideableView extends Component {
constructor(props) {
super(props);
this.state = {
opacity: new Animated.Value(this.props.visible ? 1 : 0)
}
}
animate(show) {
const duration = this.props.duration ? parseInt(this.props.duration) : 500;
Animated.timing(
this.state.opacity, {
toValue: show ? 1 : 0,
duration: !this.props.noAnimation ? duration : 0
}
).start();
}
shouldComponentUpdate(nextProps) {
return this.props.visible !== nextProps.visible;
}
componentWillUpdate(nextProps, nextState) {
if (this.props.visible !== nextProps.visible) {
this.animate(nextProps.visible);
}
}
render() {
if (this.props.removeWhenHidden) {
return (this.visible && this.props.children);
}
return (
<Animated.View style={{opacity: this.state.opacity}}>
{this.props.children}
</Animated.View>
)
}
}
HideableView.propTypes = {
visible: PropTypes.bool.isRequired,
duration: PropTypes.number,
removeWhenHidden: PropTypes.bool,
noAnimation: PropTypes.bool
}
export default HideableView;
An additional option is to apply absolute positioning via styling, setting the hidden component in out-of-screen coordinates:
<TextInput
onFocus={this.showCancel()}
onChangeText={(text) => this.doSearch({input: text})}
style={this.state.hide ? {position: 'absolute', top: -200} : {}}
/>
Unlike in some of the previous suggestions, this would hide your component from view BUT will also render it (keep it in the DOM), thus making it truly invisible.
constructor(props) {
super(props);
this.state = {
visible: true,
}
}
declare visible false so by default modal / view are hide
example = () => {
this.setState({ visible: !this.state.visible })
}
**Function call **
{this.state.visible == false ?
<View>
<TouchableOpacity
onPress= {() => this.example()}> // call function
<Text>
show view
</Text>
</TouchableOpacity>
</View>
:
<View>
<TouchableOpacity
onPress= {() => this.example()}>
<Text>
hide view
</Text>
</TouchableOpacity>
</View>
}
If you need the component to remain loaded but hidden you can set the opacity to 0. (I needed this for expo camera for instance)
//in constructor
this.state = {opacity: 100}
/in component
style = {{opacity: this.state.opacity}}
//when you want to hide
this.setState({opacity: 0})
// You can use a state to control wether the component is showing or not
const [show, setShow] = useState(false); // By default won't show
// In return(
{
show && <ComponentName />
}
/* Use this to toggle the state, this could be in a function in the
main javascript or could be triggered by an onPress */
show == true ? setShow(false) : setShow(true)
// Example:
const triggerComponent = () => {
show == true ? setShow(false) : setShow(true)
}
// Or
<SomeComponent onPress={() => {show == true ? setShow(false) : setShow(true)}}/>
You can use my module react-native-display to show/hide components.
The following example is coding in typescript with Hooks.
import React, { useState, useEffect } from "react";
........
const App = () => {
const [showScrollView, setShowScrollView] = useState(false);
......
const onPress = () => {
// toggle true or false
setShowScrollView(!showScrollView);
}
......
</MapboxGL.ShapeSource>
<View>{showScrollView ? (<DetailsScrollView />) : null}</View>
</MapboxGL.MapView>
......
}
Very Easy. Just change to () => this.showCancel() like below:
<TextInput
onFocus={() => this.showCancel() }
onChangeText={(text) => this.doSearch({input: text})} />
<TouchableHighlight
onPress={this.hideCancel()}>
<View>
<Text style={styles.cancelButtonText}>Cancel</Text>
</View>
</TouchableHighlight>
i am just using below method to hide or view a button. hope it will help you. just updating status and adding hide css is enough for me
constructor(props) {
super(props);
this.state = {
visibleStatus: false
};
}
updateStatusOfVisibility () {
this.setStatus({
visibleStatus: true
});
}
hideCancel() {
this.setStatus({visibleStatus: false});
}
render(){
return(
<View>
<TextInput
onFocus={this.showCancel()}
onChangeText={(text) => {this.doSearch({input: text}); this.updateStatusOfVisibility()}} />
<TouchableHighlight style={this.state.visibleStatus ? null : { display: "none" }}
onPress={this.hideCancel()}>
<View>
<Text style={styles.cancelButtonText}>Cancel</Text>
</View>
</TouchableHighlight>
</View>)
}
Actually, in iOS development by react-native
when I use display: 'none'
or something like below:
const styles = StyleSheet.create({
disappearImage: {
width: 0,
height: 0
}
});
The iOS doesn't load anything else of the Image component like onLoad
or etc, so I decided to use something like below:
const styles = StyleSheet.create({
disappearImage: {
width: 1,
height: 1,
position: 'absolute',
top: -9000,
opacity: 0
}
});
The only way to show or hide a component in react native is checking a value of a parameter of app state like state
or props
. I provided a complete example as below:
import React, {Component} from 'react';
import {View,Text,TextInput,TouchableHighlight} from 'react-native'
class App extends Component {
constructor(props){
super(props);
this.state={
show:false
}
}
showCancel=()=>{
this.setState({show:true})
};
hideCancel=()=>{
this.setState({show:false})
};
renderTouchableHighlight(){
if(this.state.show){
return(
<TouchableHighlight
style={{borderColor:'black',borderWidth:1,marginTop:20}}
onPress={this.hideCancel}>
<View>
<Text>Cancel</Text>
</View>
</TouchableHighlight>
)
}
return null;
}
render() {
return (
<View style={{justifyContent:'center',alignItems:'center',flex:1}}>
<TextInput
style={{borderColor:'black',borderBottomWidth:1}}
onFocus={this.showCancel}
/>
{this.renderTouchableHighlight()}
</View>
);
}
}
export default App;
If you want to hide it but keep the space occupied by the component like css's visibility: hidden
setting in the component's style opacity: 0
should do the trick.
Depending on the component other steps in disabling the functionality might be required as interaction with an invisible item is possible.
You can use the conditions for show and hide the components
constructor(){
super();
this.state ={
isVisible:true
}
}
ToggleFunction = () => {
this.setState(state => ({
isVisible: !state.isVisible
}));
};
render() {
return (
<View style={styles.MainContainer}>
{
this.state.isVisible ? <Text style= {{ fontSize: 20, color: "red", textAlign: 'center' }}> Hello World! </Text> : null
}
<Button title="Toggle Visibility" onPress={this.ToggleFunction} />
</View>
);
}
checkincheckout = () => {
this.setState({ visible: !this.state.visible })
}
render() {
return (
{this.state.visible == false ?
<View style={{ alignItems: 'center', flexDirection: 'row', marginTop: 50 }}>
<View style={{ flex: 1, alignItems: 'center', flexDirection: 'column' }}>
<TouchableOpacity onPress={() => this.checkincheckout()}>
<Text style={{ color: 'white' }}>Click to Check in</Text>
</TouchableOpacity>
</View>
</View>
:
<View style={{ alignItems: 'center', flexDirection: 'row', marginTop: 50 }}>
<View style={{ flex: 1, alignItems: 'center', flexDirection: 'column' }}>
<TouchableOpacity onPress={() => this.checkincheckout()}>
<Text style={{ color: 'white' }}>Click to Check out</Text>
</TouchableOpacity>
</View>
</View>
}
);
}
thats all. enjoy your coding...
文章标签:javascript , react-native
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