iOS Swift keyCommands 仅读取数字

Question

请考虑以下代码:

override var keyCommands: [UIKeyCommand]? {
    var commands:[UIKeyCommand] = []

    let numbers = ["0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
    for number in numbers {
        let txt = number as String
        commands.append(UIKeyCommand(input: txt, modifierFlags: [], action: #selector(keyPressed(_:))))
    }
    commands.append(UIKeyCommand(input: "\r", modifierFlags: [], action: #selector(enterPressed)))
    return commands
}

出于某种原因，只有数字被读取。这是用于模拟键盘的蓝牙条形码扫描仪。 keyCommands 无法读取字母字符还是我做错了什么？

Answer 1

多亏了 Eric Aya，我才得以完成这项工作。下面是我修改后的代码。它可能不是最优雅的解决方案，但它有效:

 override var keyCommands: [UIKeyCommand]? {
    var commands:[UIKeyCommand] = []

    let numbers = ["0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]

    for number in numbers {
        let txt = number as String
        if Int(txt) == nil {
            commands.append(UIKeyCommand(input: txt, modifierFlags: [UIKeyModifierFlags.Shift], action: #selector(keyPressed(_:))))
        } else {
            commands.append(UIKeyCommand(input: txt, modifierFlags: [], action: #selector(keyPressed(_:))))
        }
    }
    commands.append(UIKeyCommand(input: "\r", modifierFlags: [], action: #selector(enterPressed)))
    return commands
}