How to make it more nicely?
Like the following image: the center row is highlighted, the rest row gray.
Here is code:
extension ViewController: UIPickerViewDelegate{
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
let info = BeatScalar.generalRates[row]
let general = GeneralRateItem(info.cn, info.ita, info.val)
// gray every row
general.unselected()
decorateView(pickerView, row: row)
return general
}
// Here is the logic
func decorateView(_ picker: UIPickerView, row: Int){
var frame = picker.frame
frame.origin.y = frame.origin.y + frame.size.height * 0.42
frame.size.height = frame.size.height * 0.16
let mini = max(row-1, 0)
// 19 is total number
let maxi = min(18, row+1)
for i in mini...maxi{
if i != row, let item = picker.view(forRow: i, forComponent: 0) as? GeneralRateItem{
let f = item.convert(item.frame, to: picker)
if frame.intersects(f) == false{
// highlight the center row
item.selected()
}
}
}
}
func pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
return 44
}
}
extension ViewController: UIPickerViewDataSource{
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int { // 19 is total number
return 19
}
}
more code in github
I need to use func pickerView(_ pickerView: UIPickerView, viewForRow, because
The code above works fine, the drawback is that it calculates much, and hard coded with some math.
I don't really know the logic. I think the logic result is just the opposite.
while Xcode always reports,
[Assert] Attempted to call -cellForRowAtIndexPath: on the table view while it was in the process of updating its visible cells, which is not allowed. Make a symbolic breakpoint at UITableViewAlertForCellForRowAtIndexPathAccessDuringUpdate to catch this in the debugger and see what caused this to occur. Perhaps you are trying to ask the table view for a cell from inside a table view callback about a specific row? Table view: ; layer = ; contentOffset: {0, 19}; contentSize: {314, 836}; adjustedContentInset: {127.66666666666667, 0, 127.33333333333331, 0}; dataSource: ; layer = >>
How to improve the code?
I have an other idea,
access the pickerView's subview to do it
How to do it more neatly?