今天我将Xcode 6升级到beta 5（从测试版1开始），你可以想象我发现我之前完美运行的Swift应用程序充满了各种错误（好吧，从beta 1发生了很多变化）。在所有错误中，有一个我无法弄清楚如何修复。它与swift闭包有关，特别是.enumerateGroupsWithTypes方法的enumerationBlock参数。这是代码：
assetLib.enumerateGroupsWithTypes(ALAssetsGroupType(ALAssetsGroupSavedPhotos), usingBlock: {
(group: ALAssetsGroup?, stop: CMutablePointer<ObjCBool>) in
...
}, failureBlock: {
(error: NSError!) in
...
})
这在Swift（Xcode 6 beta 1）中完美无缺。但是现在，我得到了2个错误：
＆＃34; ＆＃39; UnsafeMutablePointer＆＃39;不是＆＃39;错误类型的子类型＆＃39; ＆＃34;
＆＃34;使用未申报的类型＆＃39; CMutablePointer＆＃39; ＆＃34;
很明显，CMutablePointer不再存在，所以我试图修改stop参数，如：
..., stop: UnsafeMutablePointer<ObjCBool> ...
在此更改后，第二个错误显然消失了，但第一个错误转换为：
＆＃34;无法找到＆＃39; init＆＃39;接受提供的参数＆＃34;
我甚至尝试将UnsafeMutablePointer更改为UnsafePointer，如this post所示。
修改
以下是enumerateGroupsWithTypes方法的完整代码：
assetLib.enumerateGroupsWithTypes(ALAssetsGroupType(ALAssetsGroupSavedPhotos), usingBlock: {
(group: ALAssetsGroup?, stop: UnsafeMutablePointer<ObjCBool>) in
if group != nil {
group!.setAssetsFilter(ALAssetsFilter.allPhotos())
group!.enumerateAssetsAtIndexes(NSIndexSet(index: group!.numberOfAssets()-1), options: nil, usingBlock: {
(result: ALAsset!, index: Int, stop: UnsafeMutablePointer<ObjCBool>) in
if result {
var alAssetRapresentation: ALAssetRepresentation = result.defaultRepresentation()
url = alAssetRapresentation.url()
}
})
}
else if group == nil {
assetLib.assetForURL(url, resultBlock: {
(asset: ALAsset!) in
if asset != nil {
var assetRep: ALAssetRepresentation = asset.defaultRepresentation()
var iref = assetRep.fullResolutionImage().takeUnretainedValue()
var image = UIImage(CGImage: iref)
imageView.image = image
self.view.addSubview(imageView)
let mask = CAShapeLayer()
mask.path = UIBezierPath(ovalInRect: CGRectMake(0, 0, 200, 200)).CGPath
mask.frame = CGPathGetPathBoundingBox(mask.path)
mapView.layer.mask = mask
self.view.addSubview(mapView)
}
}, failureBlock: {
(error: NSError!) in
NSLog("Error!", nil)
})
}
}, failureBlock: {
(error: NSError!) in
NSLog("Error!", nil)
})
答案 0 :(得分：7)
这是一个针对我的工作示例：此代码查找专辑“projectname”并保护此相册中的图像。如果相册不存在，则会创建相册。
注意：如果有一张具有相同名称的相册。您无法再次使用此名称创建相册。您必须使用新名称。在此示例中，projectname将按日期和时间进行扩展。
顺便说一句，Apples应用程序可以创建一个同名的相册。
func saveImage(projectName : String) { // Return a new projectname
// in the var self.newProjectName if the old one could not created
if self.isSaved { // was here bevor
return
}
let library = ALAssetsLibrary() // This object will provide the access to to the library
// List over all groups in the PhotoDirectory
// ALAssetsGroupAll is the key to select the listed groups
// possible change to type:Album
library.enumerateGroupsWithTypes(ALAssetsGroupType(ALAssetsGroupAll),
usingBlock: {(group : ALAssetsGroup!, stop : UnsafeMutablePointer<ObjCBool>) in
if group != nil { // The listing of the directory content has found an object
// Did we search for this album?
if group.valueForProperty(ALAssetsGroupPropertyName).isEqualToString(projectName) {
stop.initialize(true) // Stop the enumeration thread
library.writeImageToSavedPhotosAlbum(self.cgImage, metadata: self.ciImage?.properties(),
completionBlock: {(assetUrl, error: NSError?) -> Void in
if let theError = error?.code {
lapApp.logger.addLog("saved image failed, first try \(error?.localizedDescription) code \(theError)")
} else {
library.assetForURL(assetUrl,
resultBlock: { (asset: ALAsset!) -> Void in
group.addAsset(asset)
self.isSaved = true
return // Stop this process and leave
}, failureBlock: {
(theError: NSError!) -> Void in
lapApp.logger.addLog("error occurred, image to album at the first try: \(theError.localizedDescription) ")
})
}
})
return // write image to the found album
} else {
// Album not found, enumeration will continue
}
}
else { // The album was not found, so we will create an album
if stop.memory.boolValue { // The enumeration will go over the end of the list. The stop-signal comes some time to late?
return
}
library.addAssetsGroupAlbumWithName(projectName,
resultBlock: {(group: ALAssetsGroup?) -> Void in
if let thegroup = group { // Check for a name conflict, possible was a album with the same name deleted. IOS8 will not create this album!
// The album was correct created, now we will add the picture to the album
library.writeImageToSavedPhotosAlbum(self.cgImage, metadata: self.ciImage?.properties(), completionBlock: {
(assetUrl, error: NSError?) -> Void in
if let theError = error?.code {
lapApp.logger.addLog("save image in new album failed. \(error?.localizedDescription) code \(theError)")
} else {
library.assetForURL(assetUrl,
resultBlock: { (asset: ALAsset!) -> Void in
thegroup.addAsset(asset)
self.isSaved = true
stop.initialize(true) // Stop the enumeration thread
return
}, failureBlock: {
(theError: NSError?) -> Void in
lapApp.logger.addLog("error occurred: \(theError?.localizedDescription)")
})
}
})
return
} else { // Name conflic with a deleted album.
// Work around: Create the Album with the Projectname an extend the name with Date and time
let formatter : NSDateFormatter = NSDateFormatter()
formatter.dateFormat = "yy.MM.dd hh:mm:ss"
let extensionDate = formatter.stringFromDate(NSDate())
self.newProjectName = projectName + " " + extensionDate // This is the new projectname
library.addAssetsGroupAlbumWithName(self.newProjectName,
resultBlock: {(group: ALAssetsGroup?) -> Void in
if let theGroup = group {
library.writeImageToSavedPhotosAlbum(self.cgImage, metadata: self.ciImage?.properties(), completionBlock: {
(assetUrl, error: NSError?) -> Void in
if let theError = error {
lapApp.logger.addLog("save image with new album name failed. \(error?.localizedDescription) code \(theError) \(self.newProjectName)")
} else {
library.assetForURL(assetUrl, resultBlock: { (asset: ALAsset!) -> Void in
theGroup.addAsset(asset)
self.isSaved = true
stop.initialize(true) // Stop the enumeration thread
return
}, failureBlock: {
(theError: NSError?) -> Void in
lapApp.logger.addLog("error at write image in new album occurred: \(theError?.localizedDescription)")
})
}
})
} else {
lapApp.logger.addLog("Problem adding albums with the name \(self.newProjectName)")
}
},
failureBlock: {
(error:NSError?) -> Void in
lapApp.logger.addLog("Problem adding albums: \(error)")
})
}
},
failureBlock: {
(error:NSError?) -> Void in
lapApp.logger.addLog("Problem loading albums: \(error)")
})
}
}, failureBlock: { (error:NSError?) in lapApp.logger.addLog("Problem loading albums: \(error)") })
} // End SaveImage
答案 1 :(得分：1)
NSLog("Error!", nil)错误，应为NSLog("Error!")。
（这似乎混淆了Swift编译器并导致无关的错误消息。）