在这种情况下,如何在UIPickerView中重用视图? [英] How do I reuse a view inside UIPickerView in this case?
本文介绍了在这种情况下,如何在UIPickerView中重用视图?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
if view == nil {
let customWidth = 300
let customHeight = 300
let view = UIView(frame: CGRect(x:0, y:0, width:customWidth, height:customHeight))
let label = UILabel(frame:CGRect(x:0, y:0, width:customWidth, height:customHeight))
if let filter = filters.first(where: {$0.pickerViewRowIndex == row}) {
var leading = ""
if appPurchased == false && filter.requiresPurchase == true { leading = "🔒" }
label.text = "(leading)(filter.nameStr)"
}
label.textColor = UIColor.black
label.font = UIFont(name:"HelveticaNeue-Bold", size: 18.0)
label.textAlignment = .center
view.addSubview(label)
view.transform = CGAffineTransform(rotationAngle: 90 * (.pi/180))
label.layer.masksToBounds = false
return view
}else{
print("not nil") // console never prints this line
}
guard let reusedView = view else {
assertionFailure("pickerView label view container never set")
return view!
}
return reusedView
}
推荐答案
视图永远不会不是空的。
正确。医生说错了。实际上,在选取器视图viewForRow
中不存在重用视图这回事。你总是需要创建一个新的视图,然后将其返回。
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