Flutter - 原生交互 - 相册

环境

Flutter 3.29

macOS Sequoia 15.4.1

Xcode 16.3

iOS 13.4.1
iOS 18.5

集成image_picker

在Flutter中可以使用image_picker插件实现从相册中获取图片

添加插件

flutter中访问相册image_picker插件

¥ flutter pub add image_picker
¥ flutter pub get

Xcode工程的GeneratePluginRegistrant新增了对应的注册代码

+ (void)registerWithRegistry:(NSObject<FlutterPluginRegistry>*)registry {
...
    [FLTImagePickerPlugin registerWithRegistrar:[registry       registrarForPlugin:@"FLTImagePickerPlugin"]];
...
}

更新Xcode的pod依赖

¥ pod update

添加权限

<key>NSPhotoLibraryUsageDescription</key>
<string>需要访问相册以选择图片</string>

<!-- image_picker也支持直接拍照 -->
<key>NSCameraUsageDescription</key>
<string>需要访问相机用于拍照</string>
<key>NSMicrophoneUsageDescription</key>
<string>需要访问麦克风用于拍摄视频</string>

获取单张照片

可以使用ImagePicker().pickerImage()获取单张图片

else if (index == 2) {
  _pickImage(ImageSource.gallery),
}

Future<void> _pickImage(ImageSource source) async {
   try {
     // source值可以是相机(camera)或相册(gallery)
     final pickedFile = await ImagePicker().pickImage(source: source);

     if (pickedFile != null) {
       setState(() {
         if (mounted) {
           // pop弹窗并返回从相册中选择的图片
           Navigator.pop(context, File(pickedFile.path));
         }
       });
     }
   } catch (e) {
     debugPrint("图片选择错误: $e");
   }
 }

在上一个界面接收从相册中选择的图片并刷新界面

 floatingActionButton: FloatingActionButton(
        onPressed: () async {
          final result = await menuWidget(context: context);
          if (result != null) {
            setState(() {
              _defaultCover = result;
            });
          }
        },

        backgroundColor: Colors.orangeAccent,
        child: const Icon(Icons.add, color: Colors.white),
),

Future menuWidget({required BuildContext context}) async {
  return Navigator.push(
    context,
    PageRouteBuilder(
      opaque: false,
      barrierColor: Colors.black.withValues(alpha: 0.2),
      pageBuilder:
          (context, animation, secondaryAnimation) =>
              PopScope(canPop: true, child: MenuWidget()),
      transitionsBuilder:
          (context, animation, secondaryAnimation, child) => SlideTransition(
            position: Tween<Offset>(
              begin: const Offset(0.0, 2.4),
              end: Offset.zero,
            ).animate(animation),
            child: SlideTransition(
              position: Tween<Offset>(
                begin: Offset.zero,
                end: const Offset(0.0, 2.4),
              ).animate(secondaryAnimation),
              child: child,
            ),
          ),
    ),
  );
}

iOS

Andorid

获取多张照片

可以使用ImagePicker().pickMultiImage()获取多张图片

_pickMultiImage(),

Future<void> _pickMultiImage() async {
    try {
      // 设置最多获取9张图片
      final pickedFiles = await ImagePicker().pickMultiImage(limit: 9);
      if (pickedFiles.isNotEmpty) {
        setState(() {
          if (mounted) {
            Navigator.pop(context, pickedFiles);
          }
        });
      }
    } catch (e) {
      debugPrint("图片选择错误: $e");
    }
}

floatingActionButton: FloatingActionButton(
        onPressed: () async {
          final result = await menuWidget(context: context);
          if (result != null) {
            setState(() {
              if (result is XFile) {
                _defaultCover = result;
                /// 选择多张照片
              } else if (result is List<XFile>) {
                _defaultCover = result[0];
              }
            });
          }
        },

        backgroundColor: Colors.orangeAccent,
        child: const Icon(Icons.add, color: Colors.white),
      ),

选择多张照片在iOS平台上只在14+才生效,用的是PhotosUI.framework中的PHPicker,因为手上测试机是13.4.1设备一直无法多选图片,查看源码

- (void)pickMultiImageWithMaxSize:(nonnull FLTMaxSize *)maxSize
                          quality:(nullable NSNumber *)imageQuality
                     fullMetadata:(BOOL)fullMetadata
                            limit:(nullable NSNumber *)limit
                       completion:(nonnull void (^)(NSArray<NSString *> *_Nullable,
                                                    FlutterError *_Nullable))completion {
  [self cancelInProgressCall];
  FLTImagePickerMethodCallContext *context =
      [[FLTImagePickerMethodCallContext alloc] initWithResult:completion];
  context.maxSize = maxSize;
  context.imageQuality = imageQuality;
  context.requestFullMetadata = fullMetadata;
  context.maxImageCount = limit.intValue;

  if (@available(iOS 14, *)) {
    [self launchPHPickerWithContext:context];
  } else {
    // Camera is ignored for gallery mode, so the value here is arbitrary.
    [self launchUIImagePickerWithSource:[FLTSourceSpecification makeWithType:FLTSourceTypeGallery
                                                                      camera:FLTSourceCameraRear]
                                context:context];
  }
}

limit值传了9,但是launchUIImagePickerWithSource:context:中没有对limit做任何处理代码

- (void)launchUIImagePickerWithSource:(nonnull FLTSourceSpecification *)source
                              context:(nonnull FLTImagePickerMethodCallContext *)context {
  UIImagePickerController *imagePickerController = [self createImagePickerController];
  imagePickerController.modalPresentationStyle = UIModalPresentationCurrentContext;
  imagePickerController.delegate = self;
  ...

获取视频

使用ImagePicker().pickMedia()可以从相册获取视频文件

Future<void> _pickVideo() async {
    try {
      final pickedVideo = await ImagePicker().pickMedia();
      if (pickedVideo != null) {
        setState(() {
            
        });
      }
    } catch (e) {
      debugPrint("图片选择错误: $e");
    }
}

获取多媒体文件

使用ImagePicker().pickMultipleMedia()可以从相册获取视频和照片

Future<void> _pickMultiMedia() async {
    try {
      final pickedMedia = await ImagePicker().pickMultipleMedia();
      setState(() {
        // 页面刷新
        Navigator.pop(context, pickedMedia);
      });
    } catch (e) {
      debugPrint("图片选择错误: $e");
    }
}

参考

1. Image Picker plugin for Flutter