Expo 图像选择器:未处理的承诺拒绝:TypeError:未定义不是一个对象
2020-12-02
5745
我目前正在开发一款小型应用,我想将相机胶卷中的图像加载到应用中。我已经在 Expo Image Picker 文档的帮助下构建了一个组件来实现这一点。遗憾的是,我的 expo 客户端中总是出现以下警告,我无法从相机胶卷中选择任何图像。当我单击按钮选择它们时,它只是保持原样。
我的代码:
import React, {useEffect, useState} from 'react';
import { View, Image, TouchableOpacity, PermissionsAndroid, Alert, Platform, StyleSheet } from 'react-native';
import * as Permissions from 'expo-permissions';
import ImagePicker from 'expo-image-picker';
import { MaterialIcons } from '@expo/vector-icons'
export default function ImageChooser() {
const [imageSource, setImageSource] = useState([]);
getPermissionAsync = async () => {
const { status } = await Permissions.askAsync(Permissions.CAMERA_ROLL);
if (status !== 'granted') {
alert('Sorry, we need camera roll permissions to make this work!');
}
};
useEffect(() => {
getPermissionAsync();
}, []);
_getPhotoLibrary = async () => {
let result = await ImagePicker.launchImageLibraryAsync({
allowsEditing: true,
aspect: [4, 3]
});
if (!result.cancelled) {
setImageSource({ image: result.uri });
}
}
return (
<View style={styles.container}>
<TouchableOpacity style={styles.button} onPress={() => _getPhotoLibrary()}>
{!imageSource && <MaterialIcons name="add-a-photo" style={styles.icon} size={36} />}
{/* {imageSource && <Image source={{uri:imageSource}} style={styles.image} />} */}
</TouchableOpacity>
</View>
)
}
const styles = StyleSheet.create({
container: {
paddingLeft: 20,
paddingVertical: 10
},
button: {
flex: 1,
alignItems: 'center',
justifyContent: 'center',
width: 200,
height: 150,
borderWidth: 1,
borderColor: '#C6C6C8',
borderRadius: 5,
backgroundColor: '#fff'
},
image: {
width: 200,
height: 150
},
icon: {
color: '#C6C6C8'
}
})
我收到的警告:
[Unhandled promise rejection: TypeError: undefined is not an object (evaluating '_expoImagePicker.default.launchImageLibraryAsync')]
* components/ImageChooser.js:23:23 in _getPhotoLibrary
- node_modules/regenerator-runtime/runtime.js:63:36 in tryCatch
- node_modules/regenerator-runtime/runtime.js:293:29 in invoke
- node_modules/regenerator-runtime/runtime.js:63:36 in tryCatch
- node_modules/regenerator-runtime/runtime.js:154:27 in invoke
- node_modules/regenerator-runtime/runtime.js:189:16 in PromiseImpl$argument_0
- node_modules/react-native/node_modules/promise/setimmediate/core.js:45:6 in tryCallTwo
- node_modules/react-native/node_modules/promise/setimmediate/core.js:200:22 in doResolve
- node_modules/react-native/node_modules/promise/setimmediate/core.js:66:11 in Promise
- node_modules/regenerator-runtime/runtime.js:188:15 in callInvokeWithMethodAndArg
- node_modules/regenerator-runtime/runtime.js:211:38 in enqueue
- node_modules/regenerator-runtime/runtime.js:238:8 in exports.async
* components/ImageChooser.js:23:23 in _getPhotoLibrary
* components/ImageChooser.js:36:61 in TouchableOpacity.props.onPress
- node_modules/react-native/Libraries/Pressability/Pressability.js:691:17 in _performTransitionSideEffects
- node_modules/react-native/Libraries/Pressability/Pressability.js:628:6 in _receiveSignal
- node_modules/react-native/Libraries/Pressability/Pressability.js:524:8 in responderEventHandlers.onResponderRelease
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:265:4 in invokeGuardedCallbackImpl
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:476:2 in invokeGuardedCallback
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:500:2 in invokeGuardedCallbackAndCatchFirstError
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:597:41 in executeDispatch
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:621:19 in executeDispatchesInOrder
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2521:28 in executeDispatchesAndRelease
* [native code]:null in forEach
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:836:4 in forEachAccumulated
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2546:20 in runEventsInBatch
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2702:18 in runExtractedPluginEventsInBatch
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2639:35 in batchedUpdates$argument_0
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:17712:13 in batchedUpdates$1
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2492:29 in batchedUpdates
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2638:16 in _receiveRootNodeIDEvent
- node_modules/react-native/Libraries/Renderer/implementations/ReactNativeRenderer-dev.js:2767:27 in receiveTouches
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:416:4 in __callFunction
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:109:6 in __guard$argument_0
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:364:10 in __guard
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:108:4 in callFunctionReturnFlushedQueue
* [native code]:null in callFunctionReturnFlushedQueue
3个回答
您错误地导入了
ImagePicker
,
请使用
import * as ImagePicker from 'expo-image-picker';
以下是参考文档: https://docs.expo.io/versions/latest/sdk/imagepicker/
Phobos
2020-12-03
Expo-image-picker
需要一个插件才能访问本机代码。
确保您已将其包含在 app.json 中。
Expo-image-picker 文档
另外,不要忘记重建应用程序。
{
"expo": {
"plugins": [
[
"expo-image-picker",
{
"photosPermission": "The app accesses your photos to let you share them with your friends."
}
]
]
}
}
在您的 app.json(应用程序配置文件)中,将“expo-image-picker”数组添加到 plgins 数组。 要了解有关 app.json 的更多信息,请阅读: https://docs.expo.dev/versions/v46.0.0/config/app/
Zuraiz Zafar
2022-09-07