Robert Brusa Robert Brusa - 4 months ago 43
Swift Question

changing font and its size of a picker in swift

With Objective-C, I used the code shown below to set/change font family and size of a picker:

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view {
UILabel* tView = (UILabel*)view;
if (!tView){
tView = [[UILabel alloc] init];
// Setup label properties - frame, font, colors etc
tView.font = [UIFont fontWithName:@"Times New Roman" size:fontsize];;
}
tView.text = [_mysitedata findKeyForRow:row];
NSLog(@"C key:%@ row:%ld comp:%ld", tView.text, (long int)row, (long int)component);
return tView;
}


However, Swift does not accept a cast from UIView to UILabel and hence I can not follow this path which would look something like shown below:

func pickerView(pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView?) -> UIView {
let label = view as! UILabel
label.font = UIFont(name: "Times New Roman", size: 1.0)
label.text = pickerData[row]
return label
}


The first stament (let label ....) throuws an exception at run time:


EXC-BAD INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)

Answer

A more idiomatic Swift coding would be:

func pickerView(pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView?) -> UIView {
  guard let label = view as? UILabel else {
    preconditionFailure ("Expected a Label")
  }

  label.font = UIFont(name: "Times New Roman", size: 1.0)
  label.text = pickerData[row]
  return label
}
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