我尝试在iOS和iPadOS的模拟器/设备上使用QLThumbnailGenerator,但它不起作用。我只能获得标准的空缩略图,而不能从我的文档目录中获取丰富的文件图标。
在沙盒中处理文件有一些进展,但没有什么有用的信息。
你能让它工作吗?也许权限有问题...但是哪里出了问题?从我的应用程序中,我可以列出文件并读取(打开)它们。
@IBAction func generateDidSelect(_ sender: Any) {
let docDir = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).last
print("DOC: \(docDir)")
let absPath = URL(fileURLWithPath: docDir ?? "").appendingPathComponent("flowers.png").absoluteString
//[[NSBundle mainBundle]URLForResource:@"flowers" withExtension:@"png"];
let fileURL = URL(fileURLWithPath: absPath)
fileURL.startAccessingSecurityScopedResource()
let size = CGSize(width: 200, height: 200)
let scale = UIScreen.main.scale
let isFile = fileURL.isFile()
let exists = FileManager.default.fileExists(atPath: fileURL.path)
print("isFILE? \(isFile ? "YES" : "NO") exists? \(exists ? "YES" : "NO") \nFILE: \(fileURL)")
let request = QLThumbnailGenerationRequest(fileAtURL: fileURL, size: size, scale: scale, representationTypes: QLThumbnailGenerationRequestRepresentationTypeAll)
//request.iconMode = YES;
QLThumbnailGenerator.shared().generateRepresentations(for: request, updateHandler: { thumbnail, type, error i
DispatchQueue.main.async(execute: {
print(String(format: "*** TYPE: %ld ****", Int(type)))
let uiimage = thumbnail?.uiImage
let cgImage = thumbnail?.cgImage
if let uiimage = uiimage {
print("uiimage: \(uiimage)")
}
if let cgImage = cgImage {
print("cgImage: \(cgImage)")
}
if uiimage != nil {
self.thumbnailImageView.image = uiimage
}
if error != nil {
if let error = error {
print("ERROR: \(error)")
}
//self.thumbnailImageView.image = [UIImage imageWithContentsOfFile:fileURL.path]; // test read, works
}
})
})
}
然后我尝试将一张图片放入bundle文件夹中。
使用以下代码获取文件的URL:
Bundle.main.url(forResource: "flowers", withExtension: "png")
神奇的是它能够正常工作!但是使用fileURLWithPath
方法时则不行。
然而,当我尝试访问通过iTunes上传到应用程序文档目录中的相同文件时,出现了读取错误。
2019-10-01 12:41:27.167091+0200 test_thumb_obj[618:57118] DOC: /var/mobile/Containers/Data/Application/BE4A5950-5D24-4620-A1FE-B837222E8B64/Documents
2019-10-01 12:41:27.196739+0200 test_thumb_obj[618:57118] isFILE? YES exists? YES
FILE: file:///var/mobile/Containers/Data/Application/BE4A5950-5D24-4620-A1FE-B837222E8B64/Documents/flowers.png
2019-10-01 12:41:27.233546+0200 test_thumb_obj[618:57118] *** TYPE: 0 ****
2019-10-01 12:41:27.233788+0200 test_thumb_obj[618:57118] uiimage:
2019-10-01 12:41:27.233858+0200 test_thumb_obj[618:57118] cgImage: (DP)
< (kCGColorSpaceDeviceRGB)>
width = 493, height = 640, bpc = 8, bpp = 32, row bytes = 1984
kCGImageAlphaPremultipliedFirst | kCGImageByteOrder32Little | kCGImagePixelFormatPacked
is mask? No, has masking color? No, has soft mask? No, has matte? No, should interpolate? Yes
2019-10-01 12:41:27.234761+0200 test_thumb_obj[618:57118] *** TYPE: 1 ****
2019-10-01 12:41:27.234836+0200 test_thumb_obj[618:57118] uiimage: (null)
2019-10-01 12:41:27.234865+0200 test_thumb_obj[618:57118] cgImage: (null)
2019-10-01 12:41:27.234943+0200 test_thumb_obj[618:57118] ERROR: Error Domain=QLThumbnailErrorDomain Code=2 "No cached thumbnail"
2019-10-01 12:41:27.262228+0200 test_thumb_obj[618:57118] *** TYPE: 2 ****
2019-10-01 12:41:27.262317+0200 test_thumb_obj[618:57118] uiimage: (null)
2019-10-01 12:41:27.262349+0200 test_thumb_obj[618:57118] cgImage: (null)
2019-10-01 12:41:27.262452+0200 test_thumb_obj[618:57118] ERROR: Error Domain=QLThumbnailErrorDomain Code=0 "Could not generate a thum
bnail" UserInfo={NSUnderlyingError=0x281676940 {Error Domain=NSCocoaErrorDomain Code=256 "The file couldn’t be opened."}}
我只获得了一个 i TYPE = 0 的图像,是一个白色的空图像。
而且,与之前一样,在模拟器上也没有什么好的结果......
Error Domain=NSPOSIXErrorDomain Code=22 "couldn't issue sandbox extension com.apple.app-sandbox.read for...
有些测试我错过了,导致它无法正常工作?