Swift：如何使用上一个和下一个按钮更改 UIImage？答案

【问题标题】：Swift: How to change a UIImage with a previous and next button?Swift：如何使用上一个和下一个按钮更改 UIImage？
【发布时间】：2021-12-25 18:39:48
【问题描述】：

我有一个显示当前图像的功能和两个按钮（上一个和下一个）来显示上一个图像或下一个图像。但是我的代码有一些错误。请帮忙。泰。

import UIKit

class ViewController: UIViewController {

    

    func showImage() {
        if count < photoCollection.count {
            if let images = photoCollection[count] as? Dictionary<UIImage, String> {
                photo.image = images.keys.first
                Text.text = images.values.first
            }
        } else {
            debugPrint("Failed!")
        }
    }

    
}

【问题讨论】：

你不应该使用字典。您应该使用数组来存储数据。
但是需要使用字典。
你确定它必须是一本字典吗？这似乎是个坏主意——字典是无序的。

标签： ios swift dictionary button uiimageview

【解决方案1】：

我会使用一个字典数组：

import UIKit

class ViewController: UIViewController {
    var count = 0

    var photoCollection: [[String:Any]] = [
        ["image": UIImage(named: "P1")!, "text": "City Tavern Bathroom"],
        // Other photos
    ]

    @IBOutlet weak var photo: UIImageView!
    @IBOutlet weak var Text: UILabel!

    func showImage() {
        photo.image = photoCollection[count]["image"] as! UIImage
        Text.text = photoCollection[count]["text"] as! String
    }

    @IBAction func Previous(_ sender: UIButton) {
        guard count > 0 else {return}
        count -= 1
        showImage()
    }

    @IBAction func Next(_ sender: UIButton) {
        guard count < photoCollection.count - 1 else {return}
        count += 1
        showImage()
    }
}

您也可以在无法后退或前进时禁用按钮。

【讨论】：

【解决方案2】：

字典不是完成这项工作的正确工具，但如果您必须使用字典，您至少应该确保该键比 UIImage 更易于使用。如果你定义了一个类型来保存图像和文本，你可以使用一个整数来键入字典来访问你需要的值。

class ViewController1: UIViewController {

    struct Photo {
        let image: UIImage?
        let text: String
    }

    var count = 0

    var photoCollection: [Int: Photo] = [
        0: Photo(image: UIImage(named: "P1"), text: "City Tavern Bathroom"),
        1: Photo(image: UIImage(named: "P2"), text: "Shafer Trail, Island in the Sky District"),
        2: Photo(image: UIImage(named: "P3"), text: "Rivers Bend Group Campground"),
        3: Photo(image: UIImage(named: "P4"), text: "Delta at Lake Mead"),
        4: Photo(image: UIImage(named: "P5"), text: "Deer between Sequoias"),
        5: Photo(image: UIImage(named: "P6"), text: "Arlington House, The Robert E. Lee Memorial"),
        6: Photo(image: UIImage(named: "P7"), text: "Brink of the Lower Falls of the Yellowstone River"),
        7: Photo(image: UIImage(named: "P8"), text: "Garage Exterior"),
        8: Photo(image: UIImage(named: "P9"), text: "DSCF1199"),
        9: Photo(image: UIImage(named: "P10"), text: "The Bi-national Formation"),
    ]

    func showImage() {
        guard let item = photoCollection[count] else { return }
        photo.image = item.image
        Text.text = item.text
    }
}

【讨论】：