如何为所有按钮定义单个 UILongPressGestureRecognizer？在 swift 3

Question

我有 20 多个按钮，我想为所有按钮定义一个 UILongPressGestureRecognizer，可以吗？

到目前为止这不起作用：

let longPressGestureRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(handleLongGesture))

B_BTN_1.addGestureRecognizer(longPressGestureRecognizer)
B_BTN_2.addGestureRecognizer(longPressGestureRecognizer)

出于某种原因，longPressGestureRecognizer 仅适用于 "B_BTN_2"。

但是通过为每个声明一个手势识别器，它起作用了：

let longPressGestureRecognizer1 = UILongPressGestureRecognizer(target: self, action: #selector(handleLongGesture))
let longPressGestureRecognizer2 = UILongPressGestureRecognizer(target: self, action: #selector(handleLongGesture))

B_BTN_1.addGestureRecognizer(longPressGestureRecognizer1)
B_BTN_2.addGestureRecognizer(longPressGestureRecognizer2)

编辑：

如果你要使用@Andre 的解决方案，并且有很多按钮，请改用它来防止索引错误（需要永远）：

var buttons:[UIButton] = []
    buttons.append(B_BTN_1)
    buttons.append(B_BTN_2)
    buttons.append(B_BTN_3)
    .....

Answer 1

引自 Apple 文档：

Every gesture recognizer is associated with one view. By contrast, a view can have multiple gesture recognizers, because a single view might respond to many different gestures. For a gesture recognizer to recognize touches that occur in a particular view, you must attach the gesture recognizer to that view. When a user touches that view, the gesture recognizer receives a message that a touch occurred before the view object does. As a result, the gesture recognizer can respond to touches on behalf of the view.

https://developer.apple.com/library/content/documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/GestureRecognizer_basics/GestureRecognizer_basics.html#//apple_ref/doc/uid/TP40009541-CH2-SW21

因此，您需要为每个视图初始化手势识别器，就像您所做的那样：

But by declaring a gesture recognizer for each, it works:

let longPressGestureRecognizer1 = UILongPressGestureRecognizer(target: self, action: #selector(handleLongGesture))
let longPressGestureRecognizer2 = UILongPressGestureRecognizer(target: self, action: #selector(handleLongGesture))

B_BTN_1.addGestureRecognizer(longPressGestureRecognizer1)
B_BTN_2.addGestureRecognizer(longPressGestureRecognizer2)

Answer 2

因为@Andriy Savran 已经说过，手势识别器只能有一个视图附加到。您可以使用循环来简化设置过程...

override func viewDidLoad() {
    super.viewDidLoad()

    let button1 = UIButton(type: .system)
    let button2 = UIButton(type: .system)
    let button3 = UIButton(type: .system)
    // ...

    let buttons = [button1, button2, button3]

    for button in buttons {
        let longPressGestureRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPress(sender:)))
        button.addGestureRecognizer(longPressGestureRecognizer)
    }

}

func handleLongPress(sender: UILongPressGestureRecognizer) {
    guard let button = sender.view else {
        fatalError("could not get the button attached to the gesturerecognizer")
    }

    // do something
}

如何为所有按钮定义单个 UILongPressGestureRecognizer？在 swift 3

How to define a single UILongPressGestureRecognizer for all buttons? In swift 3

ios

swift

uilongpressgesturerecogni

swift3