Develop Reference

Giving an error with expo-camera, TypeError: undefined is not an object (evaluating '_expoCamera.CameraType.back')

I'd like help regarding the test code in the expo-camera, I am using expo go and once I run the code, it gives me this error: TypeError: undefined is not an object (evaluating '_expoCamera.CameraType.back'), here is the documentation for the expo-camera: https://docs.expo.dev/versions/latest/sdk/camera/ , I am currently using expocamera 12.3.0 and have used navigation.navigate to navigate to this tab thanks ! and here is the code I directly copied from the site
import { Camera, CameraType } from 'expo-camera';
import { useState } from 'react';
import { Button, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
export default function App() {
const [type, setType] = useState(CameraType.back);
const [permission, requestPermission] = Camera.useCameraPermissions();
if (!permission) {
// Camera permissions are still loading
return <View />;
}
if (!permission.granted) {
// Camera permissions are not granted yet
return (
<View style={styles.container}>
<Text style={{ textAlign: 'center' }}>
We need your permission to show the camera
</Text>
<Button onPress={requestPermission} title="grant permission" />
</View>
);
}
function toggleCameraType() {
setType((current) => (
current === CameraType.back ? CameraType.front : CameraType.back
));
}
return (
<View style={styles.container}>
<Camera style={styles.camera} type={type}>
<View style={styles.buttonContainer}>
<TouchableOpacity
style={styles.button}
onPress={toggleCameraType}>
<Text style={styles.text}>Flip Camera</Text>
</TouchableOpacity>
</View>
</Camera>
</View>
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
},
camera: {
flex: 1,
},
buttonContainer: {
flex: 1,
flexDirection: 'row',
backgroundColor: 'transparent',
margin: 64,
},
button: {
flex: 1,
alignSelf: 'flex-end',
alignItems: 'center',
},
text: {
fontSize: 24,
fontWeight: 'bold',
color: 'white',
},
});

Update: fixed it, just changed CameraType.back into Camera.Constants.Type.back, solved

React Native - add a masked circle overlay over image

How do I go about adding an opaque circular overlay over an image in React Native? Similar to the instagram image picker:
as trivial a task this may seem, I've had a world of trouble replicating this. Any suggestions?

As someone mentioned in the comments, the way to achieve this is with React Native Masked View.
Install it in your project by running:
npm install -S #react-native-community/masked-view
or
yarn add #react-native-community/masked-view
Then you can use it as follows. I've adapted the example from their README for you here:
import MaskedView from '#react-native-community/masked-view';
import React from 'react';
import { View } from 'react-native';
export default class App extends React.Component {
render() {
return (
<View
style={{
flex: 1,
backgroundColor: '#000000', // "Edge" background
maxHeight: 400,
}}
>
<MaskedView
style={{ flex: 1 }}
maskElement={
<View
style={{
// Transparent background mask
backgroundColor: '#00000077', // The '77' here sets the alpha
flex: 1,
}}
>
<View
style={{
// Solid background as the aperture of the lens-eye.
backgroundColor: '#ff00ff',
// If you have a set height or width, set this to half
borderRadius: 200,
flex: 1,
}}
/>
</View>
}
>
{/* Shows behind the mask, you can put anything here, such as an image */}
<View style={{ flex: 1, height: '100%', backgroundColor: '#324376' }} />
<View style={{ flex: 1, height: '100%', backgroundColor: '#F5DD90' }} />
<View style={{ flex: 1, height: '100%', backgroundColor: '#F76C5E' }} />
<View style={{ flex: 1, height: '100%', backgroundColor: '#2E6D3E' }} />
</MaskedView>
</View>
);
}
}

import React from 'react';
import {
SafeAreaView,
StyleSheet,
View,
Image,
Text
} from 'react-native';
const Test = () => {
return (
<SafeAreaView style={{flex: 1}}>
<View style={styles.container}>
<Image
source={{
uri: 'https://raw.githubusercontent.com/AboutReact/sampleresource/master/old_logo.png'
}}
//borderRadius will help to make Round Shape
style={{
width: 200,
height: 200,
borderRadius: 200 / 2
}}
/>
<Text style={styles.textHeadingStyle}>
About React
</Text>
</View>
</SafeAreaView>
);
};
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#e0dcdc',
},
textHeadingStyle: {
marginTop: 30,
fontSize: 40,
color: '#0250a3',
fontWeight: 'bold',
},
});
export default Test;

import React, { Component } from 'react';
import {
View,
StyleSheet,
Text,
ScrollView,
TouchableOpacity,
} from 'react-native';
import styles from './styles';
import { Circle, CustomHeader, CustomImage, CTNexaBold } from '../../components';
import translate from '../../translations/translate';
import { images, icons } from '../../assets'
import { widthPercentageToDP as wp, heightPercentageToDP as hp } from 'react-native-responsive-screen';
import utils from '../../utils';
import { Colors } from '../../common';
import ImagePicker from 'react-native-image-crop-picker';
class UploadProfilePicture extends Component {
constructor(props) {
super(props);
this.state = {
profileImage: '',
isProfileImage: false,
};
}
componentDidMount() {
};
changeProfilePhoto() {
ImagePicker.openPicker({
width: 300,
height: 400,
cropping: true
}).then(image => {
this.setState({
profileImage: image.path,
isProfileImage: true,
})
});
}
render() {
const { profileImage, isProfileImage } = this.state
return (
<View style={styles.container}>
{utils.statusBar('dark-content', Colors.white)}
<CustomHeader
title={<CTNexaBold customStyle={styles.customStyle} >{translate("Upload Profile Picture")}</CTNexaBold>}
{...this.props}
/>
<View style={{ flex: 0.8, alignItems: 'center', justifyContent: 'center', marginBottom: 200 }} >
<View>
<Circle
width={wp('44%')}
height={wp('44%')}
borderRadius={wp('44%')}
borderColor={'#A28A3D'}
marginVertical={40}
marginHorizontal={70}
>
<CustomImage
style={styles.userAvatar}
// source={images.iconProfile}
source={ isProfileImage ? { uri: profileImage } : images.iconProfile }
/>
</Circle>
</View>
<View style={{ marginHorizontal: wp('10%') }} >
<TouchableOpacity onPress={()=>this.changeProfilePhoto()} >
<View style={{ flexDirection: 'row', justifyContent: 'space-between' }} >
<CTNexaBold customStyle={styles.profileText} >Change Profile Photo</CTNexaBold>
<CustomImage
style={styles.containerCustomImage}
source={icons.arrowRight}
/>
</View>
</TouchableOpacity>
</View>
</View>
<View style={{ flex: 0.2, alignItems: 'center', justifyContent: 'center', marginBottom: 20 }} >
<TouchableOpacity style={styles.saveButton} >
<CTNexaBold customStyle={styles.saveButtonText} >SAVE</CTNexaBold>
</TouchableOpacity>
</View>
</View>
);
}
}
export default UploadProfilePicture;

how do i get react native to play multiple local files

i want to play multiple videos and i have this set up but the videos wont show i don't know if i have to add the path or am i just adding everything wrong from const i basically know how to play one video buy adding it to the souce but i want to play more but i don't know how to import them from a local file?
any suggestions would help thanks in advance
import React from 'react';
import { StyleSheet, Text, View, Dimensions,ImageBackground,ScrollView } from 'react-native';
import { Video } from 'expo';
import { MaterialIcons, Octicons } from '#expo/vector-icons';
const VIDEOS = [ // replace these links with links to your videos
'./spiderman.mp4',
'C:\Windows\System32\avengerproject2\spiderman.mp4',
'C:\Windows\System32\avengerproject2\spiderman.mp4'
]
export default class App extends React.Component {
state = {
currentVideo: 0,
mute: false,
shouldPlay: true,
}
handlePlayAndPause = () => {
this.setState(prevState => ({
shouldPlay: !prevState.shouldPlay
}));
}
handleVolume = () => {
this.setState(prevState => ({
mute: !prevState.mute,
}));
}
forwardButton = () => {
if (this.state.currentVideo != VIDEOS.length-1) {
this.setState({currentVideo: this.state.currentVideo + 1});
} else {
this.setState({currentVideo: 0});
}
}
backButton = () => {
if (this.state.currentVideo != 0) {
this.setState({currentVideo: this.state.currentVideo - 1});
} else {
this.setState({currentVideo: VIDEOS.length-1});
}
}
render() {
const { width } = Dimensions.get('window');
return (
<View style={styles.container}>
<ImageBackground
source={{uri:'https://wallpapercave.com/wp/aqm17QD.jpg'}}
style={{width: '100%', height: '100%'}}>
<View >
<Text style={{ textAlign: 'center', fontSize: 18,
fontWeight: 'bold' }}>Welcome spiderman</Text>
<Video source =
{{uri: VIDEOS[this.state.currentVideo]}}
shouldPlay={this.state.shouldPlay}
resizeMode="cover"
style={{ width, height: 300 }}
isMuted={this.state.mute}
/>
<View style={styles.controlBar}>
<MaterialIcons
name={this.state.mute ? "volume-mute" :
"volume-up"}
size={45}
color="white"
onPress={this.handleVolume}
/>
<MaterialIcons
name={this.state.shouldPlay ? "pause" :
"play-arrow"}
size={45}
color="white"
onPress={this.handlePlayAndPause}
/>
</View>
</View>
<View style={{flex: .25, flexDirection: 'row',
alignItems: 'center'}}>
<MaterialIcons
name={"navigate-before"}
size={150}
color="white"
onPress={this.backButton}
/>
<Text>Next Video</Text>
<MaterialIcons
name={"navigate-next"}
size={150}
color="white"
onPress={this.forwardButton}
/>
</View>
</ImageBackground>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
backgroundColor: '#B32E2E',
alignItems: 'center',
justifyContent: 'center',
},
controlBar: {
position: 'absolute',
bottom: 0,
left: 0,
right: 0,
height: 45,
flexDirection: 'row',
alignItems: 'center',
justifyContent: 'center',
backgroundColor: "rgba(0, 0, 0, 0.5)",
},
});

Your problem looks like you are unable to access to your video files. (Not sure about rest of your code also)
If you want to access any type of asset in your app, you have 2 choices.
1) Stream video from a server.
Which would allow you to just add a link of the video like you do with your local mp4 files. (https://videostoragesite.com/spiderman.mp4)
2) Add assets to your bundle.
Which you can do with Expo's asset manager, or eject your project to a vanilla react native project and bundle the mp4 files into your app using Xcode or Android Studio.

Get Touch Event on entire screen

I have a disappearing header which I want to bring back into the view on a single tap anywhere on the screen. But if I am wrapping the entire <View> inside a <TouchableX> component the PanResponder stops working. Is there a hack around this?

You do not need to warp it with Touchable component.
Add next props to root View.
onResponderGrant - make View handle touch
onStartShouldSetResponder - make View handle start

To elaborate #Nicholas Chong advice, here is the example that works for me fine. You can use onTouchStart and onTouchEnd handlers on any View via props:
<View
onTouchStart={() => doSomething()}
style={{ width: '100%', height: '100%' }}
/>
More information

onResponderGrant not working for me, and I use onTouchEnd to trigger when tap the screen, this will work

This would be an example of a implementation with a onResponderGrant
import React, { Component } from 'react';
import {
Platform,
StyleSheet,
Text,
View,
TouchableOpacity
} from 'react-native';
const instructions = Platform.select({
ios: 'Press Cmd+R to reload,\n' +
'Cmd+D or shake for dev menu',
android: 'Double tap R on your keyboard to reload,\n' +
'Shake or press menu button for dev menu',
});
export default class App extends Component<{}> {
constructor() {
super();
this.startTouch = this.startTouch.bind(this);
this.stopTouch = this.stopTouch.bind(this);
this.onTouchE = this.onTouchE.bind(this);
}
startTouch() {
console.debug("You start so don't stop!??");
}
stopTouch() {
console.debug("Why you stop??");
}
onTouchE() {
console.debug("Touchable Opacity is working!!");
}
render() {
return (
<View style={styles.container}
onResponderGrant = { () => this.startTouch() }
onResponderRelease = { () => this.stopTouch() }
onStartShouldSetResponder = { (e) => {return true} }
>
<TouchableOpacity
onPress = { () => this.onTouchE() }
>
<Text style={styles.welcome}>
Welcome to React Native!
</Text>
</TouchableOpacity>
<Text style={styles.instructions}>
To get started, edit App.js
</Text>
<Text style={styles.instructions}>
{instructions}
</Text>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: 'cornflowerblue',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
instructions: {
textAlign: 'center',
color: '#333333',
marginBottom: 5,
},
});

I have included an example of using onResponderGrant and onStartShouldSetResponder inside of a View component.
(Thanks to your previously written answer, #Mr Br)
Definitions
import { Modal, Text, View } from "react-native";
import { useState } from "react";
const [visible, setVisible] = useState(false);
const dismissFunction = () => setVisible(false);
Presentation
<Modal visible={visible} transparent style={{ alignItems: "center", height: "100%", }} >
<View onResponderGrant={dismissFunction} onStartShouldSetResponder={dismissFunction} style={{ flex: 1, backgroundColor: "#1c1c1c75", flexDirection: "column", justifyContent: "flex-end", alignItems: "center" }} >
<View style={{ backgroundColor: "#1E2124", borderRadius: 30, justifyContent: "center", alignItems: "center", height: "30%", shadowColor: "#ffffff10", shadowOpacity: 10, shadowOffset: { width: 0, height: -5 }, width: "101%" }}>
<Text style={{ textAlign: "center", color: "#ffffff", fontSize: 24, marginLeft: "10%", marginRight: "10%", marginBottom: "10%", marginTop: "5%" }}>The message of your modal!</Text>
</View>
</View>
</Modal>
Don't forget to run setVisible(true) somewhere to get the modal to show!

How to add a button in React Native?

I´m confused with this whole "no CSS" thing, but I understand why it's beneficial. All I want to do is place a button in the middle of the screen but I don't understand how styling works in React yet. This is my code:
var tapSpeed = React.createClass({
render: function() {
return (
<View style={styles.container}>
<Text style={styles.welcome}>
Tap me as fast as you can!
</Text>
<View style={styles.button}>
!
</View>
</View>
);
}
});
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#FFCCCC'
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10
},
button: {
textAlign: 'center',
color: '#ffffff',
marginBottom: 7,
border: 1px solid blue,
borderRadius: 2px
}
});

Update: use built-in Button component.
Deprecated:
Wrap your View into TouchableHighlight for iOS and TouchableNativeFeedback for Android.
var {
Platform,
TouchableHighlight,
TouchableNativeFeedback
} = React;
var tapSpeed = React.createClass({
buttonClicked: function() {
console.log('button clicked');
},
render: function() {
var TouchableElement = TouchableHighlight;
if (Platform.OS === 'android') {
TouchableElement = TouchableNativeFeedback;
}
return (
<View style={styles.container}>
<Text style={styles.welcome}>
Tap me as fast as you can!
</Text>
<TouchableElement
style={styles.button}
onPress={this.buttonClicked.bind(this)}>
<View>
<Text style={styles.buttonText}>Button!</Text>
</View>
</TouchableElement>
</View>
);
}
});

You can use built in react-native Button element.
import React, { Component } from 'react';
import { StyleSheet, View, Button, Alert, AppRegistry } from 'react-native';
class MainApp extends Component {
_onPress() {
Alert.alert('on Press!');
}
render() {
return (
<View style={styles.container}>
<View style={styles.buttonContainer}>
<Button onPress={this._onPress} title="Hello" color="#FFFFFF" accessibilityLabel="Tap on Me"/>
</View>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#FFFFFF'
},
buttonContainer: {
backgroundColor: '#2E9298',
borderRadius: 10,
padding: 10,
shadowColor: '#000000',
shadowOffset: {
width: 0,
height: 3
},
shadowRadius: 10,
shadowOpacity: 0.25
}
})
AppRegistry.registerComponent('MainApp', () => MainApp);
Read More Here.

The react-native-button package provides a button that is styled like a native button. Install it with npm install react-native-button and use it in your component like this:
var Button = require('react-native-button');
var ExampleComponent = React.createClass({
render() {
return (
<Button
style={{borderWidth: 1, borderColor: 'blue'}}
onPress={this._handlePress}>
Press Me!
</Button>
);
},
_handlePress(event) {
console.log('Pressed!');
},
});

You have two options to achieve a touchable component/button to handle user's events.
One is to use the built in Button Component. Check the docs here http://facebook.github.io/react-native/docs/button.html
Two use either TouchableHighlight or TouchableNativeFeedback or TouchableOpacity or TouchableWithoutFeedback. Think of this as a way for you to convert different areas of your app to tappable(clickable) or a way for you to create a custom button.
Each component here is different based on how it behaves once it's tapped by the user. Check the docs for more details. http://facebook.github.io/react-native/docs/touchablewithoutfeedback.html etc.
Concerning styling in react native you will need to understand flexbox layout. Check this css flexbox article all rules are applicable to react-native https://css-tricks.com/snippets/css/a-guide-to-flexbox/ except that you will have to capitalize the rules e.g align-content to alignContent

<Button
onPress={onPressLearnMore}
title="Learn More"
color="#841584"
accessibilityLabel="Learn more about this purple button"
/>

Please check react-native doc's regarding the buttons
You have more than one way to add button in your application and styling it
You can use Button tag and it's have only one way styling by color attribute, it will appearing in IOS different than Android, or by putting button in view tag with style
<View style={style.buttonViewStyle}>
<Button title="Facebook" color="blue" onPress={this.onFacebookPress} />
</View>
And check the TouchableOpacity and TouchableNativeFeedback tags
And take a lock on below link for more options to add custom buttons in your app
https://js.coach/react-native/react-native-action-button?search=button

export default class Login extends React.Component {
barcodeAction = () => {
this.props.navigation.navigate('BarCodeScanner')
}
cleverTapAction = () => {
this.props.navigation.navigate('CleverTapApp')
}
}
render() {
return (
<View style={styles.container}>
<View style={styles.buttonContainer}>
<Button
onPress={this._onPressButton}
title="Press Me"
/>
</View>
<View style={styles.buttonContainer}>
<Button
onPress={this._onPressButton}
title="Press Me"
color="#841584"
/>
</View>
<View style={styles.alternativeLayoutButtonContainer}>
<Button
onPress={this._onPressButton}
title="This looks great!"
/>
<Button
onPress={this._onPressButton}
title="OK!"
color="#841584"
/>
</View>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
},
buttonContainer: {
margin: 20
},
alternativeLayoutButtonContainer: {
margin: 20,
flexDirection: 'row',
justifyContent: 'space-between'
}
});

The Button element from react-native package does not provide built in styling feature. Ex. The "title" props will be in upper case by default. Hence, I've used an another package react-native-elements that provides nice features for Button element along with different styling options.
You can refer more details on Button from react-native-elements

import React, { Component } from 'react';
import { StyleSheet, View, TouchableOpacity, Text} from 'react-native';
var tapSpeed = React.createClass({
render: function() {
return (
<View style={styles.container}>
<TouchableOpacity>
<Text style={styles.welcome}>
Tap me as fast as you can!
</Text>
</TouchableOpacity>
<TouchableOpacity style={styles.button}>
<Text>!</Text>
</TouchableOpacity>
</View>
);
}
});
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
flexDirection: 'column',
alignItems: 'center',
backgroundColor: '#FFCCCC'
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
alignSelf: 'center'
},
button: {
justifyContent: 'center',
alignItems: 'center',
marginBottom: 7,
border: 1px solid blue,
borderRadius: 2px
}
});