在
swift 3中,该方法向我展示了“模糊地使用’enumerateObjects’”,发生了什么.我该怎么办？
extension PHFetchResult {
public func assetCollection() -> [PHAssetCollection] {
var list :[PHAssetCollection] = []
self.enumerateObjects { (object,index,stop) in
if object is PHAssetCollection {
let collection = object as! PHAssetCollection
list.append(collection)
}
}
return list
}
}
做类似这样的事.您不能直接为PHFetchResult添加扩展名,因为它有其他ObjectType作为其通用参数PHFetchResult< ObjectType> .所以你必须做点别的事.
原文链接：https://www.f2er.com/swift/319293.htmlclass FetchPhoto {
class func assetCollection() -> [PHAssetCollection] {
var list :[PHAssetCollection] = []
PHAssetCollection.fetchMoments(with: nil).enumerateObjects(EnumerationOptions.concurrent) { (collection,_,_) in
list.append(collection)
}
return list
}
}
PHAssetCollection.fetchMoments返回PHFetchResult< PHAssetCollection>这里PHAssetCollection是PHFetchResult的ObjectType.您收到了模糊错误,因为您尚未指定objectType.
class FetchPhoto {
class func assetCollection<T : PHObject>(result : PHFetchResult<T>) -> [T] {
var list : [T] = []
result.enumerateObjects(EnumerationOptions.concurrent) { (object,_) in
list.append(object)
}
return list
}
}
斯威夫特3
class PhotosHelper {
class func fetchAllLocalIdentifiersOfPhotos(completion : (_ localIdentifiers : [String]) -> ()) {
let photos : PHFetchResult<PHAsset> = PHAsset.fetchAssets(with: PHAssetMediaType.image,options: nil)
photos.enumerateObjects ({ _,_ in
// Do your operations,you can see that there is no warnings/errors in this one
})
}
}
