React Native - 在博览会弹出后安装博览会

Posted 2023-03-10

【中文标题】React Native - 在博览会弹出后安装博览会

【英文标题】：React Native - Reinstall expo after expo eject

【发布时间】：2019-07-24 20:36:22

【问题描述】：

我在使用 react-native-image-picker 库时遇到问题。因此，我尝试将 RCTCameraRoll 链接到 Xcode 库中。但是，要使用 Xcode 打开我的项目，我必须运行 expo eject。

现在，我该如何运行我的项目？运行命令时：expo start 它返回：

Property 'expo' in app.json is not an object. Please make sure app.json includes a managed Expo app config like this: "expo":"name":"My app","slug":"my-app","sdkVersion":"..."
No Expo configuration found. Are you sure this is a project directory?

【参考方案1】：

如果你想使用expo，你可以使用ImagePicker，但你不必将Expo做成一个独立的应用程序。 p>

你可以运行expo install expo-image-picker

用法

import * as React from 'react';
import  Button, Image, View  from 'react-native';
import * as ImagePicker from 'expo-image-picker';
import Constants from 'expo-constants';
import * as Permissions from 'expo-permissions';

export default class ImagePickerExample extends React.Component 
  state = 
    image: null,
  ;

  render() 
    let  image  = this.state;

    return (
      <View style= flex: 1, alignItems: 'center', justifyContent: 'center' >
        <Button
          title="Pick an image from camera roll"
          onPress=this._pickImage
        />
        image &&
          <Image source= uri: image  style= width: 200, height: 200  />
      </View>
    );
  

  componentDidMount() 
    this.getPermissionAsync();
  

  getPermissionAsync = async () => 
    if (Constants.platform.ios) 
      const  status  = await Permissions.askAsync(Permissions.CAMERA_ROLL);
      if (status !== 'granted') 
        alert('Sorry, we need camera roll permissions to make this work!');
      
    
  

  _pickImage = async () => 
    let result = await ImagePicker.launchImageLibraryAsync(
      mediaTypes: ImagePicker.MediaTypeOptions.All,
      allowsEditing: true,
      aspect: [4, 3],
    );

    console.log(result);

    if (!result.cancelled) 
      this.setState( image: result.uri );
    
  ;

【讨论】：

我收到警告：“[未处理的承诺拒绝：错误：缺少相机胶卷权限。]”使用 iOS 模拟器