Why is [UITableView appearance] messing up a UIDatePicker? - ios

Question

I'm having a weird issue when presenting a UIDatepicker as a UITextField subclas's inputView.
What's happening is that the picker is being presented but the second column is being cut by something resulting in having month names truncated at the third or fourth character. Here's a screenshot of this problem:
The whole problem is generated at the begining of the app while setting up some styles, specifically UITableView styles. The line of code responsible for this behaviour is this one:
[[UITableView appearance] setBackgroundColor:[self greyPayAppColor]];
greyPayAppColor is just some custom grey color defined elsewhere. In fact thats the exact color showing in the screenshot covering the months names.
Now, I'm really confused since I don't know how a UITableView apperance message can mess up a UIDatePicker. Another thing is that this problem only occurs with a UIDatePicker used as an inputView of a text field, not on a regular one generated by IB.
For reproduction purposes heres my UITexField subclass that I'm using. It generates two views, a UIDatePicker and a UIToolbar setting them as the text field inputView and inputAccessoryView. It also uses delegation to comunicate when the "Done" and "Cancel" buttons were pressed.
The .h file:
#import <UIKit/UIKit.h>
#protocol DatePickerTextFieldDelegate <NSObject>
#optional
- (void)didDismissDatePickerWithDate:(NSDate *)date; // If date == nil => cancel was pressed
#end
#interface DatePickerTextField : UITextField
#property (nonatomic, weak) id<DatePickerTextFieldDelegate> datePickerDelegate;
#property (nonatomic, strong) NSDate *date;
#end
The .m file:
#import "DatePickerTextField.h"
#interface DatePickerTextField ()
#property (strong, nonatomic) UIToolbar *toolBar;
#property (strong, nonatomic) UIDatePicker *datePicker;
#end
#implementation DatePickerTextField
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
[self setup];
}
return self;
}
- (void)awakeFromNib
{
[self setup];
}
- (void)setup
{
self.datePicker = [self setupDatePicker];
self.toolBar = [self setupToolBar];
self.inputView = self.datePicker;
self.inputAccessoryView = self.toolBar;
}
- (UIDatePicker *)setupDatePicker
{
UIDatePicker *datePicker = [[UIDatePicker alloc] init];
datePicker.datePickerMode = UIDatePickerModeDate;
return datePicker;
}
- (void)setDate:(NSDate *)date
{
_date = date;
if (_date) {
self.text = [self localizedDateString:_date];
[self.datePicker setDate:_date animated:NO];
}
}
- (NSString *)localizedDateString:(NSDate *)date
{
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setTimeStyle:NSDateFormatterNoStyle];
NSString *dateString = [dateFormatter stringFromDate:date];
return dateString;
}
- (UIToolbar *)setupToolBar
{
CGFloat width = [self superview].frame.size.width;
UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, width, 44)];
UIBarButtonItem *extraSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
UIBarButtonItem *cancel = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:#selector(cancelPressed)];
UIBarButtonItem *done = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:#selector(donePressed)];
toolBar.items = #[cancel,extraSpace,done];
return toolBar;
}
- (void)cancelPressed
{
[self.datePickerDelegate didDismissDatePickerWithDate:nil];
}
- (void)donePressed
{
[self.datePickerDelegate didDismissDatePickerWithDate:self.datePicker.date];
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
#end

Answer 1

I never understood why this happened but I managed to get around it by overriding the appearance call in that particular VC given that it didn't contain a tableView, like this:
// override appearence
[[UITableView appearanceWhenContainedIn:[self.superview class], nil] setBackgroundColor:[UIColor clearColor]];
I would still like to understand this relation between UITableView and UIDatepicker. If anyone know please leave a comment!
Thanks.