Question

我正在将UIStepper添加到水平UIStackView中，水平UIStackView本身在垂直UIStackView上。问题是，无论我做什么，UIStepper都不会注册任何事件。

我的代码如下

init(variableIndex: Int, variableName: String, withParentView parent: UIView, currentValue: String, readOnly: Bool) {
    // Instantiate the properties
    valueTextField = UITextField()
    valueStepper = UIStepper()
    numberOfDecimals = currentValue.components(separatedBy: ".").count > 1 ? currentValue.components(separatedBy: ".")[1].count : 1
    numericValue = Double(currentValue)!
    super.init(variableIndex: variableIndex, variableName: variableName, withParentView: parent)

    // Horizontal Stack View
    let horizontalStackView = UIStackView()
    horizontalStackView.axis = .horizontal
    horizontalStackView.alignment = .fill
    horizontalStackView.spacing = 15
    horizontalStackView.distribution = .fill
    horizontalStackView.translatesAutoresizingMaskIntoConstraints = false
    horizontalStackView.isUserInteractionEnabled = true

    // Text Field
    valueTextField.text = stringValue
    valueTextField.textAlignment = .right
    valueTextField.layer.borderWidth = 1.0
    valueTextField.layer.cornerRadius = 6.0
    valueTextField.layer.borderColor = UIColor.darkGray.cgColor
    #warning ("TODO: Enable interaction, change keyboard to numeric and add done button to keyboard")
    valueTextField.isUserInteractionEnabled = false
    valueTextField.rightView = UIView(frame: CGRect(x: 0, y: 0, width: ConfigFile.rightPadding, height: Int(valueTextField.frame.size.height)))
    valueTextField.rightViewMode = .always

    // Stepper
    valueStepper.value = numericValue
    valueStepper.stepValue = 0.1
    valueStepper.addTarget(self, action: #selector(self.stepperValueChanged(sender:)), for: .touchUpInside)
    valueStepper.addTarget(self, action: #selector(self.test(sender:)), for: .allEditingEvents)
    valueStepper.isEnabled = !readOnly

    // Create the constraints
    constraints.append(NSLayoutConstraint(item: horizontalStackView, attribute: .width, relatedBy: .equal, toItem: stackView, attribute: .width, multiplier: 1.0, constant: 0.0))

    horizontalStackView.addArrangedSubview(valueTextField)
    horizontalStackView.addArrangedSubview(valueStepper)
    stackView.addArrangedSubview(horizontalStackView)
}

@objc private func stepperValueChanged(sender: UIStepper) {
    numericValue = valueStepper.value
    let userInfo = [
        "VariableIndex": String(self.variableIndex),
        "NewValue": self.stringValue
    ]
    NotificationCenter.default.post(name: .numericVariableChanged, object: nil, userInfo: userInfo)
}

@objc private func test(sender: UIStepper) {
    print("Hi")
}

如您所见，我将事件添加到行中

valueStepper.addTarget(self, action: #selector(self.stepperValueChanged(sender:)), for: .touchUpInside)
valueStepper.addTarget(self, action: #selector(self.test(sender:)), for: .allEditingEvents)

我还尝试在第二行使用.allTouchEvents参数，但这没用。

UIStepper上方的所有视图的isUserInteractionEnabled属性均设置为true

在执行过程中，按下UIStepper会得到反馈（它会暂时变色）。

Answer 1

将.valueChanged事件与UIStepper而非.touchUpInside或.allEditingEvents一起使用。

Answer 2

我遇到的问题与here

中描述的问题相同

问题是我没有保存对正在生成的对象的任何引用，因此该对象被立即取消了初始化。我通过在保存它的ViewController中保留对它的引用来解决此问题。

UIStepper不会注册任何事件

2 个答案: