Dynamic PickerView with multiple components: Index out of range - swift

Question

I have a PickerView with 3 components based on this code. The two picker to the right change their content based on the previous selection to the left.
Unfortunately the app crashes when I change a parent picker to another one with less rows than the previews one: 🛑 Fatal Error: Index out of range.
I tried to return the child picker to their first position after selecting another parent picker, but it didn't worked out. (Please see under didSelectRow
Do you have another idea?
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 3
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if component == 0 {
return countries.count
} else if component == 1 {
let selectedCountry = pickerView.selectedRow(inComponent: 0)
return countries[selectedCountry].cities.count
} else {
let selectedCountry = pickerView.selectedRow(inComponent: 0)
let selectedCity = pickerView.selectedRow(inComponent: 1)
return countries[selectedCountry].cities[selectedCity].posts.count
}
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if component == 0 {
return countries[row].name
} else if component == 1{
let selectedCountry = pickerView.selectedRow(inComponent: 0)
return countries[selectedCountry].cities[row].name
} else {
let selectedCountry = pickerView.selectedRow(inComponent: 0)
let selectedCity = pickerView.selectedRow(inComponent: 1)
return countries[selectedCountry].cities[selectedCity].posts[row]
}
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
pickerView.reloadAllComponents()
if component == 0 {
pickerView.selectRow(0, inComponent: 1, animated: true)
pickerView.selectRow(0, inComponent: 2, animated: true)
} else if component == 1 {
pickerView.selectRow(0, inComponent: 2, animated: true)
}
}

Answer 1

When you call reloadAllComponents() in your didSelectRow you haven't updated the selected rows yet so it's crashing.
Change the order around and it should be fine.
Reset the value of the 1st component of UIPickerView when component 0 is changed might be of interest here as well.
Note pickerView.reloadAllComponents() isn't strictly necessary, as pointed out in the post above. You could just reload the ones that need to change.
A suggestion as well: Your code would be easier to read/maintain if you used say an enum to organize your components so instead of if component == 0 you could have if componentType == .country (or better yet, a switch), for example.