004-React-Native--多图选择上传

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参考资料：http://www.jianshu.com/p/488e62ed9656

一：使用react-native-image-crop-picker进行图片选择时，并没有提供多图的机制。
当你从相机选择图片时，会覆盖之前已经存在的图片。所以，今天，来一个多图选择并上传的例子，此例子中，会保存你之前已经选择的图片。例如，当前列表已经存在一张照片，当你去相册或者使用相机进行拍照时，不会覆盖当前列表已经存在的照片。

二：使用FormData进行图片上传，并根据需要进行其他参数的添加

三： Coding

pic.gif

//第三方库，需要使用npm引入
import ImagePicker from 'react-native-image-crop-picker';
import ActionSheet from '../../components/ActionSheet/ActionSheet'
import Config from '../../../Config'

import ModalProgress from '../../components/Progress/ModalProgress'

//存放数组
var dataToPost = [];

export  default class LoadingPage extends React.Component {
    static navigationOptions = ({ navigation }) => {
        const {state} = navigation;
        return {
            title: '上传信息',
            headerRight: (
                <Button
                    title="上传"
                    onPress={()=>{
                      state.params.commitPage();
                    }}
                />
            ),
        };
    };

    componentWillMount(){
        this.props.navigation.setParams({
            commitPage:this.commitPage,
        })
    }
    constructor(props){
        super(props);
        this.state={
            images: [],
        }
    }
    show() {
        let items = [
            {title: '从相册选取', onPress: () => this.openPicLib()},
            {title: '拍照一张',onPress: () => this.pickSingleWithCamera()},
        ];
        let cancelItem = {title: '关闭'};
        ActionSheet.show(items, cancelItem);
    }

    render(){
        return(
            <ScrollView>
                <View>
                    <View>
                        <View style={styles.viewPadding}>
                            {this.createImageItem()}
                        </View>
                    </View>
                    <View style={styles.itemLine}/>
                </View>
            </ScrollView>
        )
    }

    createImageItem(){
        let  imageSource = require('../../imgs/upload.png');
        let mainView;
        if(this.state.images!=null&&this.state.images.length>=9){
            mainView=null;
        }else{
            mainView=  <TouchableOpacity
                onPress={()=>{
                    this.show();
                }}>
                <Image source={imageSource} />
            </TouchableOpacity>
        }

        return(
            <View>
                <View>
                    {this.state.images ? this.state.images.map(i => <View key={i.uri}>{this.renderImage(i)}</View>) : null}
                </View>
                <View>
                    {mainView}
                </View>
            </View>
        )
    }

   //从相机获取图片
    pickSingleWithCamera=()=> {
        ImagePicker.openCamera({
            cropping: false,
             Math.round((Dimensions.get('window').width-20)),
            height: 300,
        }).then(image => {
            dataToPost.push({
                uri: image.path,
                 image.width,
                height: image.height,
            });
            this.setState({
                images: dataToPost
            });
        }).catch(
            e => alert(e)
        );
    }

//从图库或者相机进行获取,因为安卓平台不能进行多图选择，所以，需要区分不同平台
    openPicLib=()=> {
        if(Platform.OS === 'ios'){
            ImagePicker.openPicker({
                multiple: true,
                waitAnimationEnd: false,
            }).then(images => {
                for (var i=0;i<images.length;i++) {
                    dataToPost.push({
                        uri: images[i].path,
                         images[i].width,
                        height: images[i].height,
                        mime: images[i].mime,
                    });
                }
                this.setState({
                    images: dataToPost
                });
            }).catch(e =>
                alert(e)
            );

        }else{
            ImagePicker.openPicker({
                 300,
                height: 300,
                cropping: false,
                cropperCircleOverlay: false,
                compressImageMaxWidth: 480,
                compressImageMaxHeight: 640,
                compressImageQuality: 0.5,
                mediaType: 'photo',
                compressVideoPreset: 'MediumQuality'
            }).then(image => {
                dataToPost.push({
                    uri: image.path,
                     image.width,
                    height: image.height,
                    mime: image.mime
                });
                this.setState({
                    images: dataToPost
                });
            }).catch(e => {
                Alert.alert(e.message
                    ? e.message
                    : e);
            });
        }
    }

    renderImage(image) {
        return <Image style={{ 100, height: 100, resizeMode: 'contain'}} source={image} />
    }


   //数据提交
    commitPage=()=>{
        let formData = new FormData();
        if(this.state.images == null){
            alert("没有选择图片");
        } else {
            for(var i = 0;i<this.state.images.length;i++){
                var uri = this.state.images[i].uri;
                var index = uri.lastIndexOf("/");
                var name  = uri.substring(index + 1, uri.length);
                let file = {uri: uri, type: 'multipart/form-data', name: name } ;
                formData.append('file', file);
            }
        }

        //上传图片时，可以在此添加相关其他参数
        formData.append('userId', '1');
        formData.append('fileType', 'image');
        formData.append('name','time');
        formData.append('phone', '11222222');

        ModalProgress.show("数据上传中，请稍后....");
        const REQUEST_URL = Config.domain+'/upload/uploadQualifications';
        fetch(REQUEST_URL,{
            method:'POST',
            headers:{
                'Content-Type':'multipart/form-data',
                'Accept': 'application/json'
            },
            body:formData,
        }).then((response) => response.json()).then((responseJson) => {
            alert(JSON.stringify(responseJson));
            if (responseJson.status == 0) {
                ModalProgress.hide();
                {this.goBack()}
            }else{
                ModalProgress.hide();
                alert(responseJson.msg);
            }
        }).catch((error) => {
            alert(error);
            ModalProgress.hide();
        });

    }
}

image.png

作者：Time_二胡

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