ios – UIStepper：如何知道用户点击了步进器的哪个按钮(减号或加号按钮)

我怎么可能知道用户点击了步进器的哪个按钮(减号或加号按钮)？

- (IBAction)buttonStepper:(id)sender {
    int stepperValue = self.outletStepper.value;
    self.label.text = [Nsstring stringWithFormat:@"%d",stepperValue];
}

谢谢：3

解决方法

您可以,而不是addTarget：action,观察steppers值属性并要求在更改字典中接收旧值和新值

{
    UIStepper *stepper = ...;
    [stepper addobserver:self forKeyPath:@"value"
                 options:NSkeyvalueObservingOptionOld | NSkeyvalueObservingOptionNew
                 context:0];
}

- (void)observeValueForKeyPath:(Nsstring *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (object == stepper) {
        double oldValue = change[NSkeyvalueChangeOldKey];
        double newValue = change[NSkeyvalueChangeNewKey];
        double change = newValue - oldValue;
    }
}

或子类UIStepper并在重写的-setValue中进行计算：