如何在iOS中更改选择器视图所选对象的颜色

Question

How can change the selected element colour in uipickerview. have 10 elements in picker view they are all black colour .when selecting an one from 1 to 9 means the selected element want to show in blue colour. but the last element selected means it want to show red colour. how can i achieve this help me.

Answer 1

- (void)viewDidLoad
{
    [super viewDidLoad];

    arrayNo = [[NSMutableArray alloc] init];

    [arrayNo addObject:@"1"];
    [arrayNo addObject:@"2"];
    [arrayNo addObject:@"3"];
    [arrayNo addObject:@"4"];
    [arrayNo addObject:@"5"];
    [arrayNo addObject:@"6"];
    [arrayNo addObject:@"7"];
    [arrayNo addObject:@"8"];
    [arrayNo addObject:@"9"];

}

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{

    UIView *view = [pickerView viewForRow:row forComponent:component];

    UILabel *selectedLabel = (UILabel *) [view viewWithTag:1002];

    if ([[arrayNo objectAtIndex:row] isEqual:[arrayNo lastObject]]) {
        [selectedLabel setTextColor:[UIColor redColor]];
    } else {
        [selectedLabel setTextColor:[UIColor blueColor]];
    }

}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return [arrayNo count];
}

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{

    if (view) {
        NSLog(@"view exists");
    } else {

        view = [[UIView alloc] initWithFrame:CGRectZero];
        [view setTag:1001];

        UILabel *lbl=[[UILabel alloc] initWithFrame:CGRectMake(0, 0, CGRectGetWidth(pickerView.frame), 30)];
        [lbl setBackgroundColor:[UIColor clearColor]];
        [lbl setFont:[UIFont boldSystemFontOfSize:16]];
        [lbl setTextAlignment:NSTextAlignmentCenter];
        [lbl setTag:1002];
        [lbl setTextColor:[UIColor blackColor]];
        [lbl setText:[arrayNo objectAtIndex:row]];

        [view addSubview:lbl];

    }


    return view;

}

Answer 2

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
for(UIView *lview in pickerView.subviews) {
    if ([lview isKindOfClass:[UILabel class]]) {

    }
    NSLog(@"%@",lview);
}
}

By using the above code you will get all the sub view and check wheather it is label or not.

Then try to put different color to each label and then you find to your specific label, then you can do what ever you need.

The subviews order may change depending on the number of component in the picker.So, not added the exact logic.