UIDatePicker valueChanged 轮子旋转? [英] UIDatePicker valueChanged as wheels spin?

问题描述

我正在使用 UIDatePicker 用日期更新 UILabel，但我注意到 valueChanged 事件仅在车轮停止旋转.

I’m using a UIDatePicker to update UILabel with a date, but I’m noticing that the valueChanged event is only called when the wheels stop spinning.

理想情况下，如果用户轻弹一列，我希望标签中的日期随着轮子的旋转不断更新，以获得实时反馈.

Ideally if the user flicks a column, I’d like the date in the label to update continuously as the wheel spins, for a realtime sense of feedback.

这可能吗?

推荐答案

这是一个极端的解决方法，但是...

This is an extreme workaround, but...

如果您使用 UIPickerView 而不是 UIDatePicker(当然，这将需要重新实现大部分 DatePicker)，您可以在 pickerView:viewForRow:forComponent:reusingView: 委托方法中检测轮子旋转.如果行数超过了一次可以显示的行数，则每次滚轮移动时都会调用此方法.

If you use a UIPickerView instead of a UIDatePicker (which, granted, would entail re-implementing most of the DatePicker), you can detect the wheel spinning in the pickerView:viewForRow:forComponent:reusingView: delegate method. If there are more rows than can be displayed at once, this will be called every time the wheel moves.

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