我正在将图像写入文件并在mapview didSelect方法内部进行读取,这会导致图像数据读取错误。
var localImageFileUrl: URL? = nil
do {
delegate.documentDirectoryUrl = try FileManager.default.url(for: .documentDirectory,in: .userDomainmask,appropriateFor: nil,create: false)
if let data = aStruct.imageData {
localImageFileUrl = delegate.documentDirectoryUrl!.appendingPathComponent("Image.png")
UserDefaults.standard.set(localImageFileUrl,forKey: "localImageFileUrl")
try data.write(to: localImageFileUrl!)
}
}
catch {
print("error")
}
在这里进行测试就可以了。
do{
print("imageUrl0: \(localImageFileUrl)")
let imageData: Data = try Data(contentsof: localImageFileUrl as! URL)
let image = UIImage(data: imageData)
print(image)
}catch{
print("Unable to load image data: \(error)")
}
调试窗口输出:
imageUrl0: 可选(文件:///var/mobile/Containers/Data/Application/19A5A226-3CAF-4DC0-9015-40278703C5BA/Documents/Image.png)
可选(,{120,120}) 效果很好。
我通过这样的结构传递数据:
let endPtPin = GpsData.MyEndPt(latitude: Double(latitudeStr) as! Double,longitude: Double(longitudeStr) as! Double,url: localImageFileUrl! as NSURL)
在mapview didSelect方法内部,我提取了网址,并尝试访问该图像,但它给出了错误:
func mapView(_ mapView: MKMapView,didSelect view: MKAnnotationView) {
DispatchQueue.main.async {
if let thumbnailImageButton = view.leftCalloutaccessoryView as? UIButton,let url = (view.annotation as? GpsData.MyEndPt)?.thumbnailUrl
{
print("imageUrl: \(url)")
do{
let imageData: Data = try Data(contentsof: url as URL)
let image = UIImage(data: imageData)
thumbnailImageButton.setImage(image,for: UIControlState.normal)
}catch{
print("Unable to load image data: \(error)")
}
}
}
}
调试窗口显示错误:
imageUrl: 可选(file:///var/mobile/Containers/Data/Application/19A5A226-3CAF-4DC0-9015-40278703C5BA/Documents/Image.png) 2020-03-27 00:07:04.079576-0500 r2nr [9945:4518812] NSURLConnection 错误结束-代码-1002
2020-03-27 00:07:07.009134-0500 r2nr [9945:4518751] CFURLCopyResourcePropertyForKey失败,因为它被传递了URL 没有计划
无法加载图像数据:Error Domain = NSCocoaErrorDomain Code = 256 “无法打开文件“ Image.png)”。 UserInfo = {NSURL = Optional(file:///var/mobile/Containers/Data/Application/19A5A226-3CAF-4DC0-9015-40278703C5BA/Documents/Image.png)}
文件路径未更改,但无法从文件读取图像数据。怎么了?