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: