ReactNative对话框的实现

ReactNative官方的Modal在使用了预加载JS和RootView优化功能之后，就不能弹Modal窗口，而Modal窗口弹出来的前提是需要当前的Context上下文，而预加载初始化的相关工作传入的context要么是application或其它activity的上下文。

在这种情况下，我们需要实现弹窗效果就需要其它方案来解决，那么这里就是解决方案;

一、ReactNaitve JavaScript实现Dialog源码

'use strict'
import React, {Component} from 'react';
import {
    StyleSheet,
    View,
    StatusBar,
    Dimensions, TouchableWithoutFeedback
} from 'react-native';

const {width, height} = Dimensions.get('window');
const [left, top] = [0, 0];

export default class Dialog extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            isHidden: this.props.isHidden
        };
        this.position = this.props.position || "center";
        this.outSideDisappear = this.props.outSideDisappear || true;
        this.height = this.props.height || 0;
        this.contentStyle = this.props.contentStyle;
        this.margin = this.props.margin || 0;
    }

    /**
     * 隐藏对话框
     */
    dismiss = () => {
        this.setState({
            isHidden: true
        });
    }

    /**
     * 显示对话框
     */
    show = () => {
        this.setState({
            isHidden: false
        });
    }

    /**
     * 点击透明区域是否消失对话框;
     */
    onDialogOutSideClicked = () => {
        if (this.props.outSideDisappear) {
            this.dismiss();
        }
    }

    render() {
        //计算屏的高度
        let screenHeight = height - StatusBar.currentHeight;
        //计算对话框内容区域top的起点位置;
        let top = this.position == "center" ? (screenHeight - this.height) / 2
                : this.position == "top" ? this.margin
                :(screenHeight - this.height - this.margin ) ;

        return this.state.isHidden ? <View/> : (
            <View style={styles.dialog_container}>
                {
                  //对话框半透明背景
                }
                <TouchableWithoutFeedback style={styles.dialog_mask}
                                          onPress={this.onDialogOutSideClicked}>
                    <View style={styles.dialog_mask}/>
                </TouchableWithoutFeedback>
        {
                 //对话内容区域视图渲染
                }
                <View style={[
                    styles.dialog_center,
                    this.props.contentStyle,
                    {
                        height: this.height,
                        left:this.margin,
                        width:width - 2 * this.margin,
                        top: top }] }>
                    {this.props.children}
                </View>

            </View>);
    }
}

const styles = StyleSheet.create({
    dialog_container: {
        position: "absolute",
        width: width,
        height: height,
        left: left,
        top: top,
    },
    dialog_mask: {
        justifyContent: "center",
        backgroundColor: "#383838",
        opacity: 0.8,
        position: "absolute",
        width: width,
        height: height,
        left: left,
        top: top,
    },
    dialog_center: {
        position: "absolute",
        width: width,
        backgroundColor: "#FFFFFF",
        justifyContent: "center",
        alignSelf: "center",
        left: left,
    }
});

二、Dialog的使用说明

导入Dialog.js文件后，在你的界面render方法中加入如下代码.

Dialog定义了如下基本属性

<Dialog
    ref = { component=>{ this.dialog = component; } }
    outSideDisappear = { true } //是否点击半透明区域让对话框消失;
    contentStyle = { styles.dialog }
    position = "center" // 对话框内容区域布局对齐方式:"center","top","bottom", 默认值是:"center"
    height = { PixelRatio.getPixelSizeForLayoutSize(50) }
    isHidden = { this.state.isDialogShow } // 对话框默认是否隐藏,默认为false
    isStatusBarHidden = { true } //状态栏是否处于显示状态，默认为false;
    margin = { PixelRatio.getPixelSizeForLayoutSize(5) }>
        <Text style={ styles.title }>温馨提示</Text>
        <Text style={ styles.content }>确定要购买?</Text>
        <View style = { styles.dialogContent }>
            <Text style={ styles.cancel }>取消</Text>
            <Text style={ styles.ok }>确定</Text>
        </View>
</Dialog>

...

const styles = StyleSheet.create({

    dialog : {
        justifyContent:"flex-start",
        backgroundColor: "#ffffff",
        borderRadius:5,
    },

    title:{
        color:"#000000",
        alignSelf:"center",
        fontSize:18,
        height:25,
        marginTop:10,},

    content:{
        color:"#000000",
        alignSelf:"flex-start",
        height:70,
        fontSize:17,
        marginLeft:50,
        textAlignVertical:"center"},

    cancel:{
        color:"#000000",
        alignSelf:"center",
        fontSize:18,
        height:25,
        marginTop:10,
        marginRight:50},

    ok:{
        color:"#000000",
        alignSelf:"center",
        fontSize:18,
        height:25,
        marginTop:10,
        marginLeft:50},

    dialogContent:{
        flexDirection:"row",
        justifyContent:"center",
        alignItems:"center"}
    });

效果图如下

image.png