Center Align contents of a ListView in react native - ios

I have used a ListView to list some items but they're all left aligned. How to center align them without using another View wrapping the ListView?
Code for the ListView
<ListView
dataSource={this.state.dataSource}
renderRow={this.renderItem}
style={styles.listView}
/>
ListView Styling
listView: {
paddingTop: 20,
paddingBottom: 20,
}
How to do this? Thanks in advance.

You can solve this by using the contentContainerStyle ListView prop to apply the needed flexbox styles directly to the ListView's internal container, like so:
<ListView
dataSource={this.state.dataSource}
renderRow={this.renderItem}
contentContainerStyle={styles.listView}
/>
// ...
var styles = StyleSheet.create({
listView: {
flex: 1,
justifyContent: 'center',
},
});
Likewise, this also works when you need both axes centered by adding alignItems: 'center' to the listView style.

this.renderItem should be a function which renders the row. Your row should set the styles it needs. So something like this:
<ListView
dataSource={this.state.dataSource}
renderRow={this.renderItem}
style={styles.listView}
/>
renderItem: (item) {
<ItemRow item={item} />
}
And then in the ItemRow component:
render: () {
<View style={flexDirection: 'row', justifyContent: 'center'}>
<Text>{this.props.item.name</Text>
</View>
}

Related

React native, shoutem/ui : navigating back on NavigationBar does not work on iOS

I am struggling to make back navigation arrow on shoutem/ui NavigationBar work on iOS. The navigation bar looks like this and works on Android as expected (tap on the arrow navigates to specific predefined view) :
The related layout is as follows :
import {
Text,
Button,
View,
Image,
Divider,
Spinner,
NavigationBar,
Caption
} from '#shoutem/ui';
render() {
const {navigate} = this.props.navigation;
if (this.state.submitted && this.props.loading) {
return (
<Spinner style={{
flex: 1,
justifyContent: 'center',
alignItems: 'center'
}} />
);
}
return (
<Container style={{ flex: 1, backgroundColor: '#ffffff' }}>
<Content>
<NavigationBar
styleName='no-border'
hasHistory
navigateBack={() => navigate('WelcomeScreen')}
/>
<Grid>
<Row style={{ height: 100, justifyContent: 'center', alignItems: 'center', paddingTop: 100 }}>
<Image
style={{ width: 96, height: 89 }}
source={require('../login-logo.png')}
blurRadius={1} />
</Row>
//some other rows and columns
</Grid>
</Content>
</Container>
);
}
}
On Android the following works as expected. On iOS (Xcode simulator) the navbar is displayed correctly, however tapping on it does nothing. No log events nor errors are generated as well. I assume that the navbar can somehow be overlaid by some other element. However, the same problem exists with the other views with different elements inside the grid below the navbar. Does anyone have experience with this issue? What is the most likely cause and what am I doing wrong?
The "no-border" styleName applied to NavigationBar turned out to be the offending code piece in this case. Replacement with "inline" worked around the issue while introducing a slightly distinguishable border below the NavigationBar. However, this looks like a bug and the following issue has been opened in shoutem/ui GitHub repository : https://github.com/shoutem/ui/issues/398

Why does adding a parent View Tag in React Native change the style?

Adding a View parent breaks my styles, why is this happening? Does React Native's View tag have some default styles that I'm unaware of?
Below is the Button component as well as a screenshot with and without the View Tag.
class Button extends Component {
render() {
return (
<View>
<TouchableOpacity style={styles.buttonStyle}>
<Text style={styles.textStyle}>Hello</Text>
</TouchableOpacity>
</View>
);
}
}
const styles = StyleSheet.create({
textStyle: {
alignSelf: "center",
color: "#007aff",
fontSize: 16,
fontWeight: "600",
paddingTop: 10,
paddingBottom: 10
},
buttonStyle: {
flex: 1,
alignSelf: "stretch",
backgroundColor: "#fff",
borderRadius: 5,
borderWidth: 1,
borderColor: "#007aff",
marginLeft: 5,
marginRight: 5
}
});
The button is being rendered inside another component(A typical card component), if need I can provide that code as well.
Basically, your TouchableOpacity has all of your container styles, and this is going to cause the weird issue you are seeing. By defining flex:1, it means it will stretch itself to fill the area of the parent view. However, your parent view has not been flexed, so it will only fill the space that it needs to. It will however put your text component in however it seems fit, hence the weird result you are getting.
To debug this, I often will set backgroundColor: 'red', to see what flexbox is doing. In your case, i don't see the need for a parent view ? TouchableOpacity is simply an extension of view, so you should be able to do all your styling in it. If you are wanting to add a view though, i'd suggest wrapping it with your Touchable - otherwise you have the risk of messing up your onPresss. Something like
render() {
return (
<View style = {{height: 100, shadowColor: 'black', shadowRadius: 3}}> //RANDOM CARD CODE
<TouchableOpacity style={styles.buttonStyle}>
<View> //ANY STYLES HERE
<Text style={styles.textStyle}>Hello</Text>
</View>
</TouchableOpacity>
</View>
)};

Set height of ListView in React Native

I need to set width and height of ListView. While setting width works as expected, setting height has no effect and ListView is always stretching into almost bottom of the screen (there is only margin between bootom of screen and bottom of ListView). I am creating ListView in render method this way:
<ListView ref={component => this._stationsListFrom = component} style={styles.stationsList} dataSource={this.state.dataSource} renderRow={(rowData) => <Text>{rowData}</Text>} />
This is its style:
stationsList: {
backgroundColor: 'white',
height: 0,
}
I have also tried to set its height in a method by this command:
this._stationsListFrom.setNativeProps({height: 200});
When I have tried to set width using this command, it worked. But setting height does nothing.
How can I set height of ListView (for example, in the case of TextInput its not a problem) to desired value? Only way I wound is to use bottom margin, but that is not the way I want to use.
I am testing on iOS only (for the case it works differently on Android).
My code:
import React, { Component } from 'react';
import Dimensions from 'Dimensions';
import {
AppRegistry,
StyleSheet,
Text,
TextInput,
ListView,
Button,
View
} from 'react-native';
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'flex-start',
alignItems: 'flex-start',
backgroundColor: '#D8CD36',
padding: 25
},
label: {
textAlign: 'left',
color: '#333333',
fontSize: 20,
margin: 5,
},
textInput: {
height: 40,
borderColor: 'black',
borderWidth: 2,
padding: 7,
},
stationsList: {
backgroundColor: 'white',
height: 0,
},
separator: {
flex: 1,
height: StyleSheet.hairlineWidth,
backgroundColor: '#8E8E8E',
},
menuButton: {
},
},
);
export default class TestApp extends Component {
constructor(props) {
super(props);
const ds = new ListView.DataSource({rowHasChanged: (r1, r2) => r1 !== r2}); this.state = { dataSource: ds.cloneWithRows(['Žilina', 'Košice', 'Vrútky']), };
}
render() {
return (
<View style={styles.container}>
<Text style={styles.label}>
Z
</Text>
<TextInput ref={component => this._textInputFrom = component} style={styles.textInput} placeholder="Východzia stanica" onChangeText={this.fromTextChange.bind(this)} onLayout={(event) => { this.correctMenuFromWidth(event.nativeEvent.layout) }} renderSeparator={(sectionId, rowId) => <View key={rowId} style={styles.separator}/>} />
<Text style={styles.label}>
Do
</Text>
<TextInput style={styles.textInput} placeholder="Cieľová stanica"/>
<ListView ref={component => this._stationsListFrom = component} style={styles.stationsList} dataSource={this.state.dataSource} renderRow={(rowData) => <Button onPress={this.menuFromButtonPressed} style={styles.menuButton} title={rowData} />} />
</View>
);
}
correctMenuFromWidth(layout) {
const {x, y, width, height} = layout;
this._stationsListFrom.setNativeProps({marginTop: -74, width: width});
}
menuFromButtonPressed() {
};
fromTextChange() {
this._textInputFrom.setNativeProps({text: 'Kraľovany'});
this._stationsListFrom.setNativeProps({height: 200});
};
}
AppRegistry.registerComponent('TestApp', () => TestApp);
Move ListView inside wrapper and set height to wrapper:
<View style={{height: 200}}>
<ListView .../>
</View>
From ScrollView docs (ListView uses ScrollView):
Keep in mind that ScrollViews must have a bounded height in order to work, since they contain unbounded-height children into a bounded container (via a scroll interaction). In order to bound the height of a ScrollView, either set the height of the view directly (discouraged) or make sure all parent views have bounded height.

React Native WebView rendering unexpected border at bottom

This is a little tricky to describe. I'm using a react native WebView component to make a mini-browser. It's working ok, but there's a strange black border at the bottom of it which I didn't put in. It appears when scrolling to or beyond the bottom of the webpage.
You can see the thin black line above the "blah" text below. The reason for the blah text and the pink section at the bottom was to rule out a stray borderBottom* style on the WebView or its container.
Another thing to note is that the border briefly disappears when reloading the page, so it seems it's in the WebView's html. But I don't understand how or why, because a) it appears on all websites and b) it doesn't appear in other iOS browsers.
Am I doing something strange here?
Screenshot:
Elements and Styles:
<View style={styles.container as any}>
<View style={styles.header as any}>
{this.addressbarButtonProps().map(props => React.createElement(Button, { ...props, key: props.title }))}
<TextInput
ref={ADDRESSBAR_REF}
placeholder="type url"
style={{ minWidth: this.screenWidth - 50 * this.addressbarButtonProps().filter(b => !b.hidden).length - 10 }}
/>
</View>
<WebView
ref={WEBVIEW_REF}
source={{uri: this.state.uri}}
style={{ ...styles.web, width: this.screenWidth, paddingBottom: 0, padding: 0 }}
scalesPageToFit={true}
allowsInlineMediaPlayback={true}
onMessage={m => this.onMessage(m.nativeEvent.data)}
injectedJavaScript={js}
startInLoadingState={true}
/>
<Text style={{ borderTopWidth:20, borderTopColor: "red" }}>blah</Text>
</View>
const styles = {
container: {
paddingTop: 20,
flex: 1,
alignItems: "center",
justifyContent: "space-between",
backgroundColor: "#fafafa",
borderBottomColor: "pink",
borderBottomWidth: 100
},
header: {
flexDirection: "row",
alignItems: "flex-start",
justifyContent: "flex-start",
alignSelf: "stretch"
},
web: {
flex: 1,
borderBottomColor: "#fafafa",
backgroundColor: "#fafafa"
}
}
Set the backgroundColor of the WebView to transparent and the "border" won't be rendered.
<Webview style={{backgroundColor: 'transparent'}} .../>

Content hidden behind TabBarIOS with React Native

I'm building an iOS app with React Native and am implementing a TabBarIOS. The content on the tabs seems to flow behind and be obscured by the bar. In xcode I would have just unchecked the "extend edges" boxes but am not sure how to do this with React Native.
Here's an abbreviated version of what I'm trying to do. The <View> from CreateUser flows behind the tab bar. Is there an easy way to make sure content doesn't get obscured by the tab bar?
import React from 'react'
import {
StyleSheet,
Text,
TextInput,
View,
TouchableHighlight,
} from 'react-native'
export default class TabBar extends React.Component {
state = {
selectedTab: 'list'
}
render() {
return (
<TabBarIOS selectedTab={this.state.selectedTab}
unselectedTintColor="#ffffff"
tintColor="#ffe429"
barTintColor="#294163">
<TabBarIOS.Item
title="My List"
systemIcon="bookmarks"
selected={this.state.selectedTab==='list'}
onPress={() => {
this.setState({
selectedTab: 'list',
});
}}
>
<CreateUser />
</TabBarIOS.Item>
</TabBarIOS>
);
}
}
var styles = StyleSheet.create({
tabContent: {
flex: 1,
alignItems: 'center',
},
tabText: {
color: 'darkslategrey',
margin: 50,
},
});
export default class CreateUser extends React.Component{
render(){
return (
<View style={styles.container}>
<TouchableHighlight style={styles.button}>
<Text style={styles.buttonText}>LOG IN</Text>
</TouchableHighlight>
</View>
)
}
}
var styles = StyleSheet.create({
container: {
flex: 1,
flexDirection: "column",
justifyContent: "flex-end",
alignItems: 'center',
},
button: {
backgroundColor: "#ffe429",
borderRadius: 3,
height: 60,
width: 200,
margin: 7,
//flex: 1,
alignItems: "center",
justifyContent: "center",
},
buttonText: {
color: "#294163",
}
})
This was a problem for me when using a NavigatorIOS component that then rendered it's initialRoute component which contained a TabBarIOS component.
If this is the case for your scenario, you can fix it by using a ScrollView:
Add the flex layout style to your NavigatorIOS:
<NavigatorIOS
initialRoute={{
component: MyView,
title: 'My View',
}}
style={{flex: 1}}
/>
Use a ScrollView:
<TabBarIOS>
<TabBarIOS.Item
systemIcon="history"
title="A Tab">
<ScrollView>
<Text>
Hello World
</Text>
</ScrollView>
</TabBarIOS.Item>
</TabBarIOS>
In my case I needed to add flex: 1 to the style props for the top-level View of the screen.
RN Navigation docs
//MyScreen.tsx
export default () => (
<View style={{ flex: 1 }}>
...
</View>
)

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