iOS - layoutIfNeeded not creating frame in custom UITableViewCell - ios

Question

I have this class here for a custom tableview cell but in awakeFromNib, self.frame is always 0,0,0,0. I tried calling [self layoutIfNeeded] but that has no effect. I need the frame to place c in the right place in the cell. The code definitely runs (I've tried breakpoints), so why isn't it working?
#import "ChangeColourSubjectColourTableViewCell.h"
#import <QuartzCore/QuartzCore.h>
#define COLOUR_HEIGHT_DECIMAL 0.8
#define CORNER_RADIUS 6.0
#implementation ChangeColourSubjectColourTableViewCell
- (void)awakeFromNib {
// Initialization code
[self layoutIfNeeded];
//Colour View
//Size
CGRect rect;
rect.size.height = self.frame.size.height * COLOUR_HEIGHT_DECIMAL; //80% height
rect.size.width = rect.size.height;
//Position
CGFloat gap = self.frame.size.height * (1 - COLOUR_HEIGHT_DECIMAL) / 2;
rect.origin.y = gap;
rect.origin.x = self.frame.size.width - rect.size.width - gap;
UIView *c = [[UIView alloc] initWithFrame:rect];
[c setBackgroundColor:[UIColor blackColor]];
[c.layer setCornerRadius:CORNER_RADIUS];
[self addSubview:c];
_colourView = c;
}
- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
[super setSelected:selected animated:animated];
// Configure the view for the selected state
}
- (void)setColourViewColour:(UIColor *)colour {
[_colourView setBackgroundColor:colour];
}
#end

Answer 1

The awakeFromNib method is called when the cell is loaded from the xib, but the cell's frame is manage by the tableview.
You should create subviews as variables in method awakeFromNib and override method setFrame/layoutSubviews to layout your subview, the cell.frame in method layoutSubviews is always true.
you can do like this:
- (void)awakeFromNib {
// Initialization code
UIView *c = [[UIView alloc] initWithFrame:CGRectZero];
[c setBackgroundColor:[UIColor blackColor]];
[c.layer setCornerRadius:CORNER_RADIUS];
[self addSubview:c];
_colourView = c;
}
- (void)layoutSubviews {
[super layoutSubviews];
//Colour View
//Size
CGRect rect;
rect.size.height = self.frame.size.height * COLOUR_HEIGHT_DECIMAL; //80% height
rect.size.width = rect.size.height;
//Position
CGFloat gap = self.frame.size.height * (1 - COLOUR_HEIGHT_DECIMAL) / 2;
rect.origin.y = gap;
rect.origin.x = self.frame.size.width - rect.size.width - gap;
_colourView.frame = rect;
}
In iOS6 or later, you can use
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
[cell reloadUI];// you can do like this
}
// cell
- (void) reloadUI {
CGRect rect;
rect.size.height = self.frame.size.height * COLOUR_HEIGHT_DECIMAL; //80% height
rect.size.width = rect.size.height;
//Position
CGFloat gap = self.frame.size.height * (1 - COLOUR_HEIGHT_DECIMAL) / 2;
rect.origin.y = gap;
rect.origin.x = self.frame.size.width - rect.size.width - gap;
_colourView.frame = rect;
}