[英]iOS How to resize image at table view cell Swift
我使用多平台應用程序,但遇到問題,我希望在iPad上加載應用程序時要更改tableview
單元格的圖像大小。
現在我有自動布局:
我檢測到運行哪個設備應用程序時使用以下代碼:
public extension UIDevice {
static let modelName: String = {
var systemInfo = utsname()
uname(&systemInfo)
let machineMirror = Mirror(reflecting: systemInfo.machine)
let identifier = machineMirror.children.reduce("") { identifier, element in
guard let value = element.value as? Int8, value != 0 else { return identifier }
return identifier + String(UnicodeScalar(UInt8(value)))
}
func mapToDevice(identifier: String) -> String { // swiftlint:disable:this cyclomatic_complexity
#if os(iOS)
switch identifier {
case "iPod5,1": return "iPod Touch 5"
case "iPod7,1": return "iPod Touch 6"
case "iPhone3,1", "iPhone3,2", "iPhone3,3": return "iPhone 4"
case "iPhone4,1": return "iPhone 4s"
case "iPhone5,1", "iPhone5,2": return "iPhone 5"
case "iPhone5,3", "iPhone5,4": return "iPhone 5c"
case "iPhone6,1", "iPhone6,2": return "iPhone 5s"
case "iPhone7,2": return "iPhone 6"
case "iPhone7,1": return "iPhone 6 Plus"
case "iPhone8,1": return "iPhone 6s"
case "iPhone8,2": return "iPhone 6s Plus"
case "iPhone9,1", "iPhone9,3": return "iPhone 7"
case "iPhone9,2", "iPhone9,4": return "iPhone 7 Plus"
case "iPhone8,4": return "iPhone SE"
case "iPhone10,1", "iPhone10,4": return "iPhone 8"
case "iPhone10,2", "iPhone10,5": return "iPhone 8 Plus"
case "iPhone10,3", "iPhone10,6": return "iPhone X"
case "iPhone11,2": return "iPhone XS"
case "iPhone11,4", "iPhone11,6": return "iPhone XS Max"
case "iPhone11,8": return "iPhone XR"
case "iPad2,1", "iPad2,2", "iPad2,3", "iPad2,4":return "iPad 2"
case "iPad3,1", "iPad3,2", "iPad3,3": return "iPad 3"
case "iPad3,4", "iPad3,5", "iPad3,6": return "iPad 4"
case "iPad4,1", "iPad4,2", "iPad4,3": return "iPad Air"
case "iPad5,3", "iPad5,4": return "iPad Air 2"
case "iPad6,11", "iPad6,12": return "iPad 5"
case "iPad7,5", "iPad7,6": return "iPad 6"
case "iPad2,5", "iPad2,6", "iPad2,7": return "iPad Mini"
case "iPad4,4", "iPad4,5", "iPad4,6": return "iPad Mini 2"
case "iPad4,7", "iPad4,8", "iPad4,9": return "iPad Mini 3"
case "iPad5,1", "iPad5,2": return "iPad Mini 4"
case "iPad6,3", "iPad6,4": return "iPad Pro (9.7-inch)"
case "iPad6,7", "iPad6,8": return "iPad Pro (12.9-inch)"
case "iPad7,1", "iPad7,2": return "iPad Pro (12.9-inch) (2nd generation)"
case "iPad7,3", "iPad7,4": return "iPad Pro (10.5-inch)"
case "iPad8,1", "iPad8,2", "iPad8,3", "iPad8,4":return "iPad Pro (11-inch)"
case "iPad8,5", "iPad8,6", "iPad8,7", "iPad8,8":return "iPad Pro (12.9-inch) (3rd generation)"
case "AppleTV5,3": return "Apple TV"
case "AppleTV6,2": return "Apple TV 4K"
case "AudioAccessory1,1": return "HomePod"
case "i386", "x86_64": return "Simulator \(mapToDevice(identifier: ProcessInfo().environment["SIMULATOR_MODEL_IDENTIFIER"] ?? "iOS"))"
default: return identifier
}
#elseif os(tvOS)
switch identifier {
case "AppleTV5,3": return "Apple TV 4"
case "AppleTV6,2": return "Apple TV 4K"
case "i386", "x86_64": return "Simulator \(mapToDevice(identifier: ProcessInfo().environment["SIMULATOR_MODEL_IDENTIFIER"] ?? "tvOS"))"
default: return identifier
}
#endif
}
return mapToDevice(identifier: identifier)
}()
}
我的想法是,在表格視圖
如果modelName.range(of:“ iPad”)!=無
我想更改圖像尺寸,例如200x200;
調整圖像大小不會影響您的約束。 因此,您可能還需要更新它們。 目前-您可以通過以下方式調整圖像大小:
import UIKit
extension UIImage {
/// Returns a image that fills in newSize
func resizedImage(newSize: CGSize) -> UIImage {
guard self.size != newSize else { return self }
UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0);
self.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
/// Returns a resized image that fits in rectSize, keeping it's aspect ratio
/// Note that the new image size is not rectSize, but within it.
func resizedImageWithinRect(rectSize: CGSize) -> UIImage {
let widthFactor = size.width / rectSize.width
let heightFactor = size.height / rectSize.height
var resizeFactor = widthFactor
if size.height > size.width {
resizeFactor = heightFactor
}
let newSize = CGSize(width: size.width/resizeFactor, height: size.height/resizeFactor)
let resized = resizedImage(newSize)
return resized
}
}
我仍在我的應用程序中使用此代碼。 所以放心
// Tests
guard let url = NSURL(string: "http://placehold.it/300x150") else { fatalError("Bad URL") }
guard let data = NSData(contentsOfURL: url) else { fatalError("Bad data") }
guard let img = UIImage(data: data) else { fatalError("Bad data") }
let outImageFit = img.resizedImageWithinRect(CGSize(width: 200, height: 200))
let outImageFill = img.resizedImage(CGSize(width: 200, height: 200))
您可以使用自動布局。 只需為ImageView的高度和寬度約束創建IBOutlet。
public func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
//check for iPad and set the constraint values to 200*200
if modelName.range(of:"iPad") != nil
{
cell.imageViewHeightConstraint.constant = 200
cell.imageViewWidthConstraint.constant = 200
}
else
{
cell.imageViewHeightConstraint.constant = 100
cell.imageViewWidthConstraint.constant = 100
}
}
您甚至可以從情節提要中執行相同操作,只需選擇高度或寬度約束,然后為iPad添加另一個常量。
----請檢查以下屏幕截圖,了解如何在情節提要中為iPad添加常量。 1.選擇約束。 從右側的屬性菜單中單擊+圖標。 2.為所有類型的iPad選擇“緊湊型緊湊型”並添加變形。 3.設置iPad的常數。
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