how to change <Text> value dynamically React Native - react-native

I'm using react-native. I want to change the text data in Render according to the data I have taken in MYSQL. When ItemDURUM = 0, it says Order Pending, and when itemDURUM = 1, it says Order Confirmed. At the moment 0 and 1 value is waiting for the text value of the order is waiting. What is the problem? Now I'm pulling variable 0 and 1 from MYSQL without problems
export default class usrFirst extends React.Component {
import React, { Component } from "react";
import { Text } from 'react-native';
import { Cell, Section, TableView } from 'react-native-tableview-simple';
constructor(props) {
super(props)
this.state = {
itemDURUM:[]
}
responseMUSTERISIPARISDURUM() {
fetch('http://....php', {
method: 'POST',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
},
body: JSON.stringify({
BOYLAM: this.state...,
ENLEM: this.state....
})
}).then((response) => response.text())
.then((responseJson) => {
if(responseJson.length > 0)
{
this.setState({itemDURUM : responseJson});
}
}).catch((error) => {
console.error(error);
});
}
render() {
return (
<Cell cellStyle="RightDetail" title=<Text style={{color:'#00a7c0',fontWeight: "bold"}}>Durum</Text> detail= { this.state.itemDURUM === '0'? <Text style={{color:'#0094ff',fontWeight: "bold"}}>Order Pending</Text>: <Text style={{color:'#ff1706',fontWeight: "bold"}}>Order Confirmed</Text>} />
}
}

Your render method has some issues. I'm not sure where you call responseMUSTERISIPARISDURUM but try to change your render method to
render() {
return (
<Cell
cellStyle="RightDetail"
title={<Text style={{ color: '#00a7c0', fontWeight: "bold" }}>Durum</Text>}
detail={
this.state.itemDURUM === '0'
? <Text style={{ color: '#0094ff', fontWeight: "bold" }}>Order Pending</Text>
: <Text style={{ color: '#ff1706', fontWeight: "bold" }}>Order Confirmed</Text>
}
/>
)
}

Related

How to make a QR code scanner in React native using expo?

When I run https://snack.expo.io/#sushil62/qr-code-scanner in the expo which works fine, but when copy the same code given in App.js file, after running the application the camera opens but it shows no result while scanning, and
in expo also when changing the snack version 33 or higher it does not work there too.
import React, { Component } from 'react';
import { Alert, Linking, Dimensions, LayoutAnimation, Text, View, StatusBar, StyleSheet, TouchableOpacity } from 'react-native';
import { BarCodeScanner, Permissions } from 'expo';
export default class App extends Component {
state = {
hasCameraPermission: null,
lastScannedUrl: null,
};
componentDidMount() {
this._requestCameraPermission();
}
_requestCameraPermission = async () => {
const { status } = await Permissions.askAsync(Permissions.CAMERA);
this.setState({
hasCameraPermission: status === 'granted',
});
};
_handleBarCodeRead = result => {
if (result.data !== this.state.lastScannedUrl) {
LayoutAnimation.spring();
this.setState({ lastScannedUrl: result.data });
}
};
render() {
return (
<View style={styles.container}>
{this.state.hasCameraPermission === null
? <Text>Requesting for camera permission</Text>
: this.state.hasCameraPermission === false
? <Text style={{ color: '#fff' }}>
Camera permission is not granted
</Text>
: <BarCodeScanner
onBarCodeRead={this._handleBarCodeRead}
style={{
height: Dimensions.get('window').height,
width: Dimensions.get('window').width,
}}
/>}
{this._maybeRenderUrl()}
<StatusBar hidden />
</View>
);
}
_handlePressUrl = () => {
Alert.alert(
'Open this URL?',
this.state.lastScannedUrl,
[
{
text: 'Yes',
onPress: () => Linking.openURL(this.state.lastScannedUrl),
},
{ text: 'No', onPress: () => {} },
],
{ cancellable: false }
);
};
_handlePressCancel = () => {
this.setState({ lastScannedUrl: null });
};
_maybeRenderUrl = () => {
if (!this.state.lastScannedUrl) {
return;
}
return (
<View style={styles.bottomBar}>
<TouchableOpacity style={styles.url} onPress={this._handlePressUrl}>
<Text numberOfLines={1} style={styles.urlText}>
{this.state.lastScannedUrl}
</Text>
</TouchableOpacity>
<TouchableOpacity
style={styles.cancelButton}
onPress={this._handlePressCancel}>
<Text style={styles.cancelButtonText}>
Cancel
</Text>
</TouchableOpacity>
</View>
);
};
}
const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'center',
justifyContent: 'center',
backgroundColor: '#000',
},
bottomBar: {
position: 'absolute',
bottom: 0,
left: 0,
right: 0,
backgroundColor: 'rgba(0,0,0,0.5)',
padding: 15,
flexDirection: 'row',
},
url: {
flex: 1,
},
urlText: {
color: '#fff',
fontSize: 20,
},
cancelButton: {
marginLeft: 10,
alignItems: 'center',
justifyContent: 'center',
},
cancelButtonText: {
color: 'rgba(255,255,255,0.8)',
fontSize: 18,
},
});
It would be very nice if someone suggests me to solve this or give me an example(such as downgrading the expo version) so that I can implement this.
You can use
expo-barcode-scanner
Run expo install expo-barcode-scanner
Usage
You must request permission to access the user's camera before attempting to get it. To do this, you will want to use the Permissions API. You can see this in practice in the following example.
import * as React from 'react';
import {
Text,
View,
StyleSheet,
Button
} from 'react-native';
import Constants from 'expo-constants';
import * as Permissions from 'expo-permissions';
import {
BarCodeScanner
} from 'expo-barcode-scanner';
export default class BarcodeScannerExample extends React.Component {
state = {
hasCameraPermission: null,
scanned: false,
};
async componentDidMount() {
this.getPermissionsAsync();
}
getPermissionsAsync = async() => {
const {
status
} = await Permissions.askAsync(Permissions.CAMERA);
this.setState({
hasCameraPermission: status === 'granted'
});
};
render() {
const {
hasCameraPermission,
scanned
} = this.state;
if (hasCameraPermission === null) {
return <Text > Requesting
for camera permission < /Text>;
}
if (hasCameraPermission === false) {
return <Text > No access to camera < /Text>;
}
return ( <
View style = {
{
flex: 1,
flexDirection: 'column',
justifyContent: 'flex-end',
}
} >
<
BarCodeScanner onBarCodeScanned = {
scanned ? undefined : this.handleBarCodeScanned
}
style = {
StyleSheet.absoluteFillObject
}
/>
{
scanned && ( <
Button title = {
'Tap to Scan Again'
}
onPress = {
() => this.setState({
scanned: false
})
}
/>
)
} <
/View>
);
}
handleBarCodeScanned = ({
type,
data
}) => {
this.setState({
scanned: true
});
alert(`Bar code with type ${type} and data ${data} has been scanned!`);
};
}
Note: Passing undefined to the onBarCodeScanned prop will result in no scanning. This can be used to effectively "pause" the scanner so that it doesn't continually scan even after data has been retrieved.
Allow all the permisions which gets popped.
You're good to go!!
Hope this helps.

why does FlatList keep loading forever?

I am using FlatList to write an infinite scroll, but it keeps sending request to my server forever. please see the code blow. I don't find any article clarify when the next page will load, what exactly does the onEndReached will be triggered.
import React, { Component } from 'react';
import { View, Text, FlatList, StyleSheet, ActivityIndicator, AsyncStorage } from 'react-native';
import { connect } from 'react-redux';
import { loadOrders } from '../redux/modules/Order';
import OrderListItem from './OrderListItem';
import { forOwn, isEmpty, reduce } from 'lodash';
class OrderList extends Component {
constructor(props) {
super(props);
this.state = {
page: 1,
error: null,
};
}
componentDidMount() {
this.loadOrders();
}
loadOrders = () => {
const { page } = this.state;
AsyncStorage.getItem("userToken")
.then((value) => {
return `Bearer ${value}`;
})
.then((userToken) => {
return this.props.loadOrders(page, { Authorization: userToken });
})
.then((response) => {
this.setState({
error: response.error || null,
});
})
.catch(error => {
this.setState({ error});
})
;
}
handleLoadMore = () => {
this.loadOrders();
};
onPressItem = (id: string) => {
};
keyExtractor = (item, index) => `order-item-${item.id}`;
renderItem = ({item}) => (
<OrderListItem
order={item}
onPressItem={this.onPressItem}
/>
);
renderSeparator = () => {
return (
<View
style={{
height: 1,
width: "86%",
backgroundColor: "#CED0CE",
marginLeft: "14%"
}}
/>
);
};
renderFooter = () => {
if (!this.props.loading) return null;
return (
<View
style={{
paddingVertical: 20,
borderTopWidth: 1,
borderColor: "#CED0CE"
}}
>
<ActivityIndicator animating size="large" />
</View>
);
};
render() {
const { orders} = this.props;
if (orders.length> 0) {
return (
<View containerStyle={styles.container} >
<FlatList
data={orders}
keyExtractor={this.keyExtractor}
renderItem={this.renderItem}
ListFooterComponent={this.renderFooter}
ItemSeparatorComponent={this.renderSeparator}
onEndReached={this.handleLoadMore}
onEndReachedThreshold={0.5}
/>
</View>
);
}
return <View>
<Text>empty</Text>
</View>
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
borderTopWidth: 0,
borderBottomWidth: 0
},
item: {
padding: 16,
borderBottomWidth: 1,
borderBottomColor: '#ccc'
}
});
const mapStateToProps = state => {
let order = state.get('order').toJS();
return {
orders: isEmpty(order.entities) ? [] : reduce(order.entities, (result, value) => {
result.push({ key: value.id, ...value });
return result;
}, []),
loading: order.loading
};
};
const mapDispatchToProps = {
loadOrders
};
export default connect(mapStateToProps, mapDispatchToProps)(OrderList);
the if part is false , but the onEndReached methods is still called, I must be insane.
the
Change this
onEndReachedThreshold={0.5}
to this:
onEndReachedThreshold={0}
Right now you're calling the end reached when you're halfway through. You can also try adding this to the FlatList:
legacyImplementation = {true}
If this still won't work I would recommend doing the 'pull' onRefresh. A nice example for you: https://www.youtube.com/watch?v=pHLFJs7jlI4
i met the problem too, in my case:
renderFooter somethings render null(height: 0) when loaded, but render ActivityIndicator when loading, and ActivityIndicator has its heigth bigger than 0(null's height)
when heigth change from 0 to ActivityIndicator's height, it will call onEndReached again
and you say the if part is false, i think its because it's not really false。
when code really run in FlatList, the if part is true, so it call onEndReached, and then the _scrollMetrics.contentLength or this._sentEndForContentLength has changed for some reason before your console in chrome. which makes the if part return false
above is all my thought for now, and i am still debugging for this problem, hope this answer will help you all

React-native-multiple-select: Cannot read the property 'getSelectedItemsExt' of undefined

I am building an App and referring this link
i implemented same code for my App, but i am getting error "Cannot read the property 'getSelectedItemsExt' of undefined".
One more error is "submit" button is also not showing up. I have tried all the ways but failed.
import React, { Component } from 'react';
import { AppRegistry, StyleSheet, TextInput, View, ListView, Alert, Button, Platform, ToastAndroid, TouchableOpacity, ActivityIndicator, Text, Picker, ScrollView }
from 'react-native';
import { StackNavigator } from 'react-navigation';
import MultiSelect from 'react-native-multiple-select';
class manage_publishers extends Component {
static navigationOptions = {
title: 'Manage Publishers',
};
constructor() {
super()
this.state = {
isLoading: true,
selectedPublishers1:[],
publishersByCategory: [],
publishersByClient: [],
publishersByGroup: [],
dataSource:[]
}
}
componentDidMount()
{
const base64 = require('base-64');
fetch('APIURL'+this.props.navigation.state.params.id,
{
method: 'GET',
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json',
"Authorization": "Basic " + base64.encode("ABC:XYZ")
}
}).then((response) => response.json()
)
.then((responseJson) => {
this.setState({
categories: responseJson.PublisherByCategory,
}, function () {
});
})
.catch((error) => {
console.log("error in category");
console.log(error);
});
}
onSelectedPublishersByCategoryChange = (publishersByCategory) => {
console.log(publishersByCategory);
this.setState({ publishersByCategory });
}
render() {
const { navigate } = this.props.navigation;
if (this.state.isLoading) {
return (
<View style={{ flex: 1, paddingTop: 20 }}>
<ActivityIndicator />
</View>
);
}
return ([
<View style={{flex: 1,paddingTop: (Platform.OS === 'ios') ? 20 : 20, padding: 5}}>
<Text style={{ padding: 5, fontSize: 35, backgroundColor: '#2196F3', marginBottom: 7 }}>
Manage Publishers
</Text>
<MultiSelect
items={this.state.categories}
uniqueKey="id"
ref={(component) => { this.multiSelect = component }}
onSelectedItemsChange={this.onSelectedPublishersByCategoryChange}
selectedItems={this.state.publishersByCategory}
selectText="Publishers by Category"
searchInputPlaceholderText="Search Publisher..."
onChangeInput={ (text)=> console.log(text)}
altFontFamily="ProximaNova-Light"
tagRemoveIconColor="#CCC"
tagBorderColor="#CCC"
tagTextColor="#CCC"
selectedItemTextColor="#CCC"
selectedItemIconColor="#CCC"
itemTextColor="#000"
displayKey="name"
searchInputStyle={{ color: '#CCC' }}
submitButtonColor="#CCC"
submitButtonText="Submit"
/>
</View>,
<View>
{this.multiSelect.getSelectedItemsExt(selectedItems)}
</View>
]);
}
}
});
module.exports = manage_publishers;
Please have a look at this and provide me solution, I'll be very thankful .
I had that same issue, and I solved adding a AND condition:
{this.multiSelect && this.multiSelect.getSelectedItemsExt(selectedItems)}
If you are using functional components you can do like this,
create ref like this,
const multiSelect = useRef(null)
Access the getSelectedItemsExt function like this,
<View>
{multiSelect.current && multiSelect.current.getSelectedItemsExt &&
multiSelect.current.getSelectedItemsExt(countries)}
</View>
It happened because you called a method before the reference has been set.
Use this code:
<View>
{ this.multiSelect ? this.multiSelect.getSelectedItemsExt(selectedItems) : null}
</View>
Reference to this issue:
https://github.com/toystars/react-native-multiple-select/issues/58#issuecomment-364136438

Image URI won't load when using setState

My <Image/> remains blank even though I am console logging the URI value.
I am getting the URI from an API. The URI I'm getting is definitely https as well.
My code looks like this:
constructor(props){
super(props)
this.state = {
img: ''
}
}
componentDidMount() {
this.getImage(this.props.id)
}
getImage(id){
_this = this;
fetch(`someURL${userId}`, {
method: 'get',
headers: { Accept: 'application/json', 'Content-Type': 'application/json' },
})
.then(response => response.json())
.then((responseJson) => {
_this.setState({
img: responseJson.pic_url,
});
});
}
render() {
if (this.state.img) {
return (
<Image
resizeMode="cover"
style={{height: 50, width: 50}}
source={{uri: this.state.img}}
/>
}
return(
<View/>
)
}
If I just put the link into the URI directly like source={{uri: 'https://my-link'}} it works. I need to be able to use state though b/c the link is coming from my api.
I've created a snack expo with the following code:
import React, { Component } from 'react';
import { Image, Text, View, StyleSheet } from 'react-native';
import { Constants } from 'expo';
export default class App extends Component {
constructor() {
super();
this.state = {
imageUri: '',
};
}
componentWillMount() {
const _this = this
fetch('https://jsonplaceholder.typicode.com/photos/1')
.then(res => res.json())
.then(json => {
_this.setState({
imageUri: json.url.replace('http', 'https')
});
})
}
render() {
return (
<View style={styles.container}>
<Text style={styles.welcome}>
Image Test!
</Text>
{
this.state.imageUri ? (
<Image
resizeMode="cover"
source={{uri: this.state.imageUri}}
style={{height: 200, width: 200}}
/>
) : null
}
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'center',
justifyContent: 'center',
paddingTop: Constants.statusBarHeight,
backgroundColor: '#ecf0f1',
},
});
And it works just fine. The url that I get from the API is http, so I had to change it to https because it wouldn't work otherwise. Maybe that is your problem.
replace this
source={uri: this.state.img}
with
source={{uri: this.state.img}} // it will work if path is proper
So you are actually getting the response from your API? Did you print your URL inside your fetch method?
You don't need _this = this; as arrow functions are already binding this. However I think it shouldn't be a problem.
You have a mistake in your fetch.then
It should be:
.then( (response) => response.json())
You missed the brackets around response

POST data request on server via react native?

Basically what i'm trying to do is, on click of login button it should take my input data and check whether the data is valid for authentication and send back response to user and display on UI. After authentication it should be redirected to home screen. I tried using fetch but it's not working. Below is the code:
import React, { Component } from 'react';
import {
AppRegistry,
Text,
Image,
View,
StyleSheet,
TextInput,
Linking,
Alert,
Navigator
} from 'react-native';
import { Button } from 'react-native-elements';
import t from 'tcomb-form-native';
const Form = t.form.Form;
// here we are: define your domain model
const Email = t.subtype(t.Str, (email) => {
const reg = /^(([^<>()\[\]\\.,;:\s#"]+(\.[^<>()\[\]\\.,;:\s#"]+)*)|(".+"))#((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
return reg.test(email);
});
const LoginFields = t.struct({
username: Email, // a required string
password: t.String, // a required string
});
const options = {
fields: {
password: {
type: 'password',
placeholder: 'Password',
error: 'Password cannot be empty'
},
username: {
placeholder: 'e.g: abc#gmail.com',
error: 'Insert a valid email'
}
}
}; // optional rendering options (see documentation)
export class ChildComponent extends Component {
render() {
if(this.props.result) {
var res = this.props.result.map((item, i) => {
return(
<Text key={i}>{item.useremail}</Text>
)
})
}
return (
<View>
{res}
</View>
)
}
}
export default class Login extends Component {
constructor(props) {
super(props);
this.state = {
buttonState: true,
value: {}
}
}
_onSubmit() {
const value = this.refs.form.getValue();
if (value) { // if validation fails, value will be null
console.log(value);
// value here is an instance of LoginFields
}
componentDidMount() {
fetch('http://192.168.100.160:6016/admin/login', {
method: 'POST',
headers: {
'Accept': 'application/x-www-form-urlencoded',
'Content-Type': 'application/x-www-form-urlencoded',
},
body: JSON.stringify({
useremail: 'kirti#pws.com',
userpassword: '1234',
})
})
.then((response) => response.json())
.then((responseJson) => {
this.setState ({
data: responseJson.admin/login
})
})
}
this.props.navigator.push({
id: 'Home'
});
}
onChange = () => {
const value = this.refs.form.getValue();
if(value) {
this.setState({
value,
buttonState: false
});
}
}
render() {
return (
<View style={styles.container}>
<View style={styles.header}>
</View>
<View style={styles.content}>
<Text style={styles.contentHeader}>
Pateast Login
</Text>
<View style={styles.loginFormContent}>
<Form
ref="form"
type={LoginFields}
options={options}
value={this.state.value}
onChange={this.onChange}
/>
<Text style={{color: 'blue', marginBottom: 10}}
onPress={() => Linking.openURL('https://www.google.co.in')}>
Forgot Password?
</Text>
<Button
raise
icon={{name: 'key', type: 'octicon'}}
onPress={this._onSubmit.bind(this)}
title="Login"
disabled={this.state.buttonState}
accessibilityLabel="Ok, Great!"
/>
</View>
</View>
<View style={styles.footer}>
</View>
<ChildComponent status={this.state.status} result={this.state.data} />
</View>
);
}
}
const styles = StyleSheet.create(
{
container: {
flex: 1
},
contentHeader: {
// fontFamily: 'sans-serif-condensed',
fontWeight: 'bold',
fontSize: 40,
alignSelf: 'center',
marginBottom: 30
},
header : {
flex: 0.5,
backgroundColor: '#008080'
},
content: {
flex: 10,
backgroundColor: '#f8f8ff',
justifyContent: 'center'
},
loginFormContent: {
marginHorizontal: 20
},
footer: {
flex: 0.5,
backgroundColor: '#008080'
},
loginText: {
fontSize: 20,
marginBottom: 10
},
inputFields: {
fontSize: 20,
borderStyle: 'solid',
borderColor: '#000000',
borderRadius: 30,
marginBottom: 10
}
}
);
you were just one step away from your goal. The only thing you have to change is your body object in your post request. This object has to be a FormData https://developer.mozilla.org/de/docs/Web/API/FormData
Try to set the body like this:
let data = new FormData();
data.append("useremail", 'kirti#pws.com');
data.append("userpassword", '1234');
After that your fetch request should look like this:
fetch('http://192.168.100.160:6016/admin/login', {
method: 'POST',
headers: {
'Accept': 'application/x-www-form-urlencoded',
'Content-Type': 'application/x-www-form-urlencoded',
},
body: data
}
...