React Native - 在图像上添加蒙版圆圈覆盖

Question

我如何 go 关于在 React Native 中的图像上添加不透明的圆形覆盖？ 类似于 instagram 图像选择器：

这似乎是一项微不足道的任务，但我在复制它时遇到了麻烦。 有什么建议么？

Answer 1

正如评论中提到的那样，实现这一点的方法是使用React Native Masked View 。

通过运行将其安装到您的项目中：

npm install -S @react-native-community/masked-view

或者

yarn add @react-native-community/masked-view

然后您可以按如下方式使用它。 我在这里为您改编了他们README中的示例：

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>
    );
  }
}

Answer 2

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;

Answer 3

 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;