没有textview的iphone键盘

Question

是否可以在没有文本视图的情况下在 iphone 应用程序中调出键盘？还是我必须有一个不可见的文本视图？

如果是这样，您如何以编程方式创建一个文本视图，然后调出键盘（无需用户点击文本视图）？我能找到的唯一示例使用界面生成器..

Answer 1

UIKeyInput是你的朋友：

protocol KeyboardInputControlDelegate: class {
    func keyboardInputControl( keyboardInputControl:KeyboardInputControl, didPressKey key:Character)
}

class KeyboardInputControl: UIControl, UIKeyInput {

    // MARK: - properties

    weak var delegate: KeyboardInputControlDelegate?

    // MARK: - init

    override init(frame: CGRect) {
        super.init(frame: frame)

        addTarget(self, action: Selector("onTouchUpInside:"), forControlEvents: .TouchUpInside)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    // MARK: - UIView

    override func canBecomeFirstResponder() -> Bool {
        return true
    }

    // MARK: - methods

    dynamic private func onTouchUpInside(sender: KeyboardInputControl) {
        becomeFirstResponder()
    }

    // MARK: - UIKeyInput

    var text:String = ""

    func hasText() -> Bool {
        return text.isEmpty
    }

    func insertText(text: String) {
        self.text = text
        for ch in text {
            delegate?.keyboardInputControl(self, didPressKey: ch)
        }
    }

    func deleteBackward() {
        if !text.isEmpty {
            let newText = text[text.startIndex..<text.endIndex.predecessor()]
            text = newText
        }
    }
}

示例用法。点击红色视图并查看 Xcode 控制台输出：

class ViewController: UIViewController, KeyboardInputControlDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let kic = KeyboardInputControl(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        kic.delegate = self
        kic.backgroundColor = UIColor.redColor()
        view.addSubview(kic)
    }

    func keyboardInputControl(keyboardInputControl: KeyboardInputControl, didPressKey key: Character) {
        println("Did press: \(key)")
    }
}

Answer 2

经过一番挖掘，我找到了this。这是非官方的，但我敢打赌它有效。

UIKeyboard *keyboard = [[[UIKeyboard alloc] initWithFrame: CGRectMake(0.0f, contentRect.size.height - 216.0f, contentRect.size.width, 216.0f)] autorelease];
        [keyboard setReturnKeyEnabled:NO];
        [keyboard setTapDelegate:editingTextView];
        [inputView addSubview:keyboard];

Answer 3

显示键盘的唯一（有效）方法是拥有一个作为第一响应者的文本字段。 您可以通过在隐藏的文本字段上调用 ​​becomeFirstResponder 以编程方式将其隐藏并使其成为第一响应者。

您可以通过执行以下操作以编程方式创建 UITextView（假设存在 aRect 和视图）

var textView = [[[UITextView alloc] initWithFrame:aRect] autorelease];
[view addSubview:textView];

[textView becomeFirstResponder];

Answer 4

这些东西的工作方式是通过NSNotificationCenter 发布/订阅模型。首先你需要使用addObserver:selector:name:object:，然后你可以尝试使用this：

[[NSNotificationCenter defaultCenter] postNotification:[NSNotification notificationWithName:NSTextDidBeginEditingNotification object:self]];

但我不确定您会收到或需要注册哪些通知才能获取键盘输入字符值。祝你好运，黑客愉快:)