我正在尝试在 Swift 上实现委托模式.该过程包括一个弹出窗口,该弹出窗口从文本视图上的文本选择中的 UIMenuItem 显示.这个弹出框是一个包含一些颜色的 TableViewController.当点击单元格(或颜色)时,所选文本的颜色会从黑色变为所选颜色.我在发送类中有以下协议:
I'm trying to implement the delegation pattern on Swift. The process consists in a popover that is displayed from a UIMenuItem in a text selection on a textView. This popover is a TableViewController that contains some colors. When a cell (or color) is tapped, the selected text changes its color from black to the selected color. I have the following protocol in the sending class:
protocol SelectedColorDelegate { func didSelectColorCell(color: UIColor) }然后在发送类中我创建了这个属性:
Then in the sending class I created this property:
var colorCellDelegate: SelectedColorDelegate?在发送类的tableViewController(popover)的didSelectRowAtIndexPath方法中,我分配了需要的参数:
In the method didSelectRowAtIndexPath of the tableViewController (popover) that is the sending class, I assigned the required parameter:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { let color = arrayOfColorValues[indexPath.row] self.colorCellDelegate?.didSelectColorCell(color: color) }在我的 ViewController 接收类中,我设置了 SelectedColorDelegate 协议,并使用此方法符合它,旨在更改 textColor:
In my receiving class that is a ViewController I set the protocol SelectedColorDelegate, and conformed to it with this method, aimed to change the textColor:
func didSelectColorCell(color: UIColor) { let textRange = noteTextView.selectedRange let string = NSMutableAttributedString(attributedString: noteTextView.attributedText) string.addAttribute(NSForegroundColorAttributeName, value: color, range: textRange) noteTextView.attributedText = string noteTextView.selectedRange = textRange }但最后一个方法从未被调用,点击弹出框的单元格什么也不做,我错过了什么或做错了什么?谢谢!!:)
But the last method is never called, tapping the cell of the popover does nothing, what am I missing or doing wrong? Thanks!! :)
推荐答案首先定义你的协议只针对类
First of all define your protocol as only for classes
protocol SelectedColorDelegate: class { func didSelectColorCell(color: UIColor) }其次,我们希望我们的委托被弱保留
Secondly we want our delegate to be weakly retained
weak var colorCellDelegate: SelectedColorDelegate?最后在显示其他视图或在 viewDidLoad 中设置委托,例如:
Finally set delegate when you show other view or in viewDidLoad eg:
class YourViewController: SelectedColorDelegate { final override func viewDidLoad() { super.viewDidLoad() self.colorCellDelegate = self } }教程 - 如何在 Swift 中创建弱委托
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