在 React Natural 中，如何将一个视图放在另一个视图的上面，其中一部分位于后面的视图的界限之外？

Add the following style to the "floating" view:

position: 'absolute'

You may also need to add a top and left value for positioning.

You can use zIndex for placing a view on top of another. It works like the CSS z-index property - components with a larger zIndex will render on top.

You can refer: Layout Props

Snippet:

    <ScrollView>
<StatusBar backgroundColor="black" barStyle="light-content" />
<Image style={styles.headerImage} source=\{\{ uri: "http://www.artwallpaperhi.com/thumbnails/detail/20140814/cityscapes%20buildings%20hong%20kong_www.artwallpaperhi.com_18.jpg" }}>
<View style={styles.back}>
<TouchableOpacity>
<Icons name="arrow-back" size={25} color="#ffffff" />
</TouchableOpacity>
</View>
<Image style={styles.subHeaderImage} borderRadius={55} source=\{\{ uri: "https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Albert_Einstein_1947.jpg/220px-Albert_Einstein_1947.jpg" }} />
</Image>


const styles = StyleSheet.create({
container: {
flex: 1,
backgroundColor: "white"
},
headerImage: {
height: height(150),
width: deviceWidth
},
subHeaderImage: {
height: 110,
width: 110,
marginTop: height(35),
marginLeft: width(25),
borderColor: "white",
borderWidth: 2,
zIndex: 5
},

You can use react-native-view-overflow plugin for placing a view on top of another. It works like the CSS z-index property.

import ViewOverflow from 'react-native-view-overflow';


<ViewOverflow />
<View style={[styles2.cardBox, { marginTop: 50 }]}>
<View style={[styles2.cardItem]} >
<Text style={styles2.cardHeader}>userList</Text>
</View>
<View style={[styles2.cardContent]}>
<Text style={styles2.text}>overflow: "visible"</Text>
</View>
<View style={[styles2.cardItemFooter]} >
<Text style={styles2.cardTextFooter}>...</Text>
</View>
</View>
</ViewOverflow>


const styles2 = StyleSheet.create({
cardBox: {
borderLeftWidth: 0,
borderTopWidth: 0,
backgroundColor: "transparent",
borderWidth: 1,
borderColor: "#d0d0d0",
width: '94%',
alignSelf: 'center',
height: 200,
position: "relative",
borderRadius: 15,
overflow: "visible" // doesn't do anything
},
cardContent: {
textAlign: "right",
backgroundColor: "transparent",
marginTop: 15,
alignSelf: 'flex-end',
padding: 5,
},
cardHeader: {
color: '#fff',
fontFamily: 'Vazir',
fontSize: 12
},
cardItem: {
backgroundColor: "#3c4252",
borderRadius: 3,
position: "absolute",
top: -10,
right: -5,
width: 50,
height: 20,
paddingRight: 5,
},
})

The above solutions were not working for me. I solved it by creating a View with the same background colour as the parent and added negative margin to move the image upwards.

<ScrollView style=\{\{ backgroundColor: 'blue' }}>
<View
style=\{\{
width: '95%',
paddingLeft: '5%',
marginTop: 80,
height: 800,
}}>
<View style=\{\{ backgroundColor: 'white' }}>


<Thumbnail square large source=\{\{uri: uri}} style=\{\{ marginTop: -30 }}/>
<Text>Some Text</Text>
</View>
</View>
</ScrollView>

and I got the following result.

You can use this OverlayContainer. The trick is to use absolute with 100% size. Check below an example:

// @flow


import React from 'react'
import { View, StyleSheet } from 'react-native'


type Props = {
behind: React.Component,
front: React.Component,
under: React.Component
}


// Show something on top of other
export default class OverlayContainer extends React.Component<Props> {
render() {
const { behind, front, under } = this.props


return (
<View style={styles.container}>
<View style={styles.center}>
<View style={styles.behind}>
{behind}
</View>
{front}
</View>
{under}
</View>
)
}
}


const styles = StyleSheet.create({
container: {
flex: 1,
alignItems: 'center',
height: '100%',
justifyContent: 'center',
},
center: {
width: '100%',
height: '100%',
alignItems: 'center',
justifyContent: 'center',
},
behind: {
alignItems: 'center',
justifyContent: 'center',
position: 'absolute',
left: 0,
top: 0,
width: '100%',
height: '100%'
}
})

The easiest way to achieve this is with a negative margin.

const deviceWidth = RN.Dimensions.get('window').width


a: {
alignItems: 'center',
backgroundColor: 'blue',
width: deviceWidth,
},
b: {
marginTop: -16,
marginStart: 20,
},

import React, {Component} from 'react';
import {StyleSheet, View} from 'react-native';




export default class App extends Component {
render() {
return (
<View>// you need to wrap the two Views an another View
<View style={styles.box1}></View>
<View style={styles.box2}></View>
</View>
);
}
}


const styles = StyleSheet.create({
box1:{
height:100,
width:100,
backgroundColor:'red'
},
box2:{
height:100,
width:100,
backgroundColor:'green',
position: 'absolute',
top:10,
left:30


},
});

You can use elevation property for Android if you don't mind the shadow.

{
elevation:1
}

<SafeAreaView style=\{\{ flex: 1 }} >
<View style=\{\{ height: Dimensions.get('window').height / 2, backgroundColor: 'blue', justifyContent: 'center' }}>
<Text style=\{\{ fontSize: 25, alignSelf: 'center' }} >A</Text>
<View style=\{\{ justifyContent: 'center', height: 100, width: 100, backgroundColor: 'yellow', position: 'absolute', left: 20, top: Dimensions.get('window').height / 2 - 70 }}>
<Text style=\{\{ fontSize: 22, alignSelf: 'center' }} >B</Text>
</View>
</View>
</SafeAreaView>

Try this:

style = \{\{position: 'absolute', bottom: 20, left: 20, elevation: 100}}

Based on the example above i've created a component which stacks all childeren on top of each other. You could even nest OverlayContainers inside OverlayContainers.

Usage:

<OverlayContainer>
<View style=\{\{backgroundColor:'red', width:150, height: 150}}></View>
<View style=\{\{backgroundColor:'yellow', width:50, height: 50}}></View>
<Text>Just some text</Text>
</OverlayContainer>

Output:

import React, { FC, PropsWithChildren } from 'react'
import { StyleSheet, View } from 'react-native'


export const OverlayContainer: FC<PropsWithChildren<unknown>> = (props) => {
return (
<View style={styles.container}>
{props.children.map((child, index) => (
<View style={styles.child} key={index}>
{child}
</View>
))}
</View>
);
}
const styles = StyleSheet.create({
container: {
flex: 1,
height: '100%',
},
child: {
position: 'absolute',
left: 0,
top: 0,
width: '100%',
height: '100%'
}
})