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[英]Expo: Unhandled promise rejection: TypeError: undefined is not an object (evaluating 'props.navigation')]
[英]Expo Image Picker: Unhandled promise rejection: TypeError: undefined is not an object
我目前正在開發一個小型應用程序,我想將相機膠卷中的圖像加載到應用程序中。 我已經在其文檔中的 Expo Image Picker 的幫助下構建了一個組件。 可悲的是,我總是在我的 expo 客戶端中收到以下警告,並且我無法從相機膠卷中挑選任何圖像。 當我單擊 select 它們的按鈕時,它就保持原樣。
我的代碼:
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
您錯誤地導入了ImagePicker
,
使用import * as ImagePicker from 'expo-image-picker';
這是參考文檔: https://docs.expo.io/versions/latest/sdk/imagepicker/
讓您將其包含在 app.json 中。
{
"expo": {
"plugins": [
[
"expo-image-picker",
{
"photosPermission": "The app accesses your photos to let you share them with your friends."
}
]
]
}
}
在您的 app.json(應用程序配置文件)中將“expo-image-picker”數組添加到 plgins 數組。 要了解有關 app.json 的更多信息,請閱讀: https://docs.expo.dev/versions/v46.0.0/config/app/
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