本文介绍了React Native实现进度条弹框，分享给大家

我们在上传或者下载文件时候，希望有一个进度条弹框去提醒用户取当前正在上传或者下载，也允许用去取点击取消上传或者下载。

首先实现进度条。

import React, { PureComponent} from 'react';import { StyleSheet, View, Animated, Easing,} from 'react-native';class Bar extends PureComponent { constructor(props) { super(props); this.progress = new Animated.Value(this.props.initialProgress || 0); } static defaultProps = { style: styles, easing: Easing.inOut(Easing.ease) } componentWillReceiveProps(nextProps) { if (this.props.progress >= 0 && this.props.progress !== nextProps.progress) { this.update(nextProps.progress); } } shouldComponentUpdate() { return false; } update(progress) { Animated.spring(this.progress, { toValue: progress }).start(); } render() { return ( <View style={[styles.background, this.props.backgroundStyle, this.props.style]}> <Animated.View style={[styles.fill, this.props.fillStyle, { width: this.progress.interpolate({ inputRange: [0, 100], outputRange: [0 * this.props.style.width, 1 * this.props.style.width], })} ]} /> </View> ); }}var styles = StyleSheet.create({ background: { backgroundColor: '#bbbbbb', height: 5, overflow: 'hidden' }, fill: { backgroundColor: 'rgba(0, 122, 255, 1)', height: 5 }});export default Bar;

进度条的值我们用动画实现，避免使用state不断去重新render渲染界面，同时设置shouldComponentUpdate返回值为false，避免重新render。

实现进度条弹框。

import React, { PropTypes, PureComponent} from 'react';import { View, StyleSheet, Modal, Text, Dimensions, TouchableOpacity} from 'react-native';import Bar from './Bar';const { width} = Dimensions.get('window');class ProgressBarDialog extends PureComponent { constructor(props) { super(props); } static propTypes = { ...Modal.propTypes, title: PropTypes.string, canclePress: PropTypes.func, cancleText: PropTypes.string, needCancle: PropTypes.bool }; static defaultProps = { animationType: 'none', transparent: true, progressModalVisible: false, onShow: () => {}, onRequestClose: () => {}, onOutSidePress: () => {}, title: '上传文件', cancleText: '取消是', canclePress: () => {}, needCancle: true } render() { const { animationType, transparent, onRequestClose, progress, title, canclePress, cancleText, needCancle, progressModalVisible } = this.props; return ( <Modal animationType={animationType} transparent={transparent} visible={progressModalVisible} onRequestClose={onRequestClose}> <View style={styles.progressBarView}> <View style={styles.subView}> <Text style={styles.title}> {title} </Text> <Bar ref={this.refBar} style={{marginLeft: 10,marginRight: 10,width:width - 80}} progress={progress} backgroundStyle={styles.barBackgroundStyle} /> <View style={styles.progressContainer}> <Text style={styles.progressLeftText}> {`${progress}`}% </Text> <Text style={styles.progressRightText}> {`${progress}`}/100 </Text> </View> {needCancle && <View style={styles.cancleContainer}> <TouchableOpacity style={styles.cancleButton} onPress={canclePress}> <Text style={styles.cancleText}> {cancleText} </Text> </TouchableOpacity> </View> } </View> </View> </Modal> ); }}const styles = StyleSheet.create({ progressBarView: { flex:1, justifyContent: 'center', alignItems: 'center', backgroundColor: 'rgba(0,0,0,0.2)' }, barStyle: { marginLeft: 10, marginRight: 10, width:width - 80 }, progressLeftText: { fontSize: 14 }, cancleContainer: { justifyContent: 'center', alignItems: 'flex-end' }, progressRightText: { fontSize: 14, color: '#666666' }, barBackgroundStyle: { backgroundColor: '#cccccc' }, progressContainer: { flexDirection: 'row', padding: 10, justifyContent: 'space-between' }, subView: { marginLeft: 30, marginRight: 30, backgroundColor: '#fff', alignSelf: 'stretch', justifyContent: 'center' }, progressView: { flexDirection: 'row', padding: 10, paddingBottom: 5, justifyContent: 'space-between' }, title: { textAlign: 'left', padding:10, fontSize: 16 }, cancleButton: { padding:10 }, cancleText: { textAlign: 'right', paddingTop: 0, fontSize: 16, color: 'rgba(0, 122, 255, 1)' }});export default ProgressBarDialog;

props

modal的props - 这些都是modal的属性

animationType - 动画类型

transparent - 是否透明

progressModalVisible - 是否可见

onShow - 弹框出现

onRequestClose - 弹框请求消失(比如安卓按返回键会触发这个方法)

onOutSidePress - 点击弹框外部动作

title - 弹框的标题

cancleText - 取消的文字

canclePress - 取消动作

needCancle - 是否需要取消按钮

使用代码

import React , { PureComponent} from 'react';import { View} from 'react-native';import ProgressBarDialog from './ProgressBarDialog';class Upload extends PureComponent { constructor(props) { this.state = { progress: 0, progressModalVisible: false }; } refProgressBar = (view) => { this.progressBar = view; } showProgressBar = () => { this.setState({ progressModalVisible: true }); } dismissProgressBar = () => { this.setState({ progress: 0, progressModalVisible: false }); } setProgressValue = (progress) => { this.setState({ progress }); } onProgressRequestClose = () => { this.dismissProgressBar(); } canclePress = () => { this.dismissProgressBar(); } render() { return ( <View> <ProgressBarDialog ref={this.refProgressBar} progress={this.state.progress} progressModalVisible={this.state.progressModalVisible} onRequestClose={this.onProgressRequestClose} canclePress={this.canclePress} needCancle={true} /> </View> ) }}export default Upload;

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。