Question

I am trying to update the UITableViewCell view with a different type of theme.
I have a few themes but cannot get them to work correctly.

@interface CustomRowBackground : UIView {
CGColorRef topStroke;
CGColorRef lightColor;
CGColorRef darkColor;
CGColorRef bottomStroke; //also known as separator
CGColorRef borderColor;
}

- (id)initWithFrame:(CGRect)frame topStroke:(CGColorRef)top lightColor:(CGColorRef)light   darkColor:(CGColorRef)dark bottomStroke:(CGColorRef)bottom borderColor:(CGColorRef)border;
@end

- (id)initWithFrame:(CGRect)frame topStroke:(CGColorRef)top lightColor:(CGColorRef)light    darkColor:(CGColorRef)dark bottomStroke:(CGColorRef)bottom borderColor:(CGColorRef)border
{
   self = [super initWithFrame:frame];
if (self) {
    // Initialization code
    topStroke = top;
    lightColor = light;
    darkColor = dark;
    bottomStroke = bottom;
    borderColor = border;



}
return self;
}

Now in my UIViewController, .h file, I extend the UIColor class with a helper method

@interface UIColor (BIExtras)
+(UIColor *)colorWithR:(CGFloat)red G:(CGFloat)green B:(CGFloat)blue A:(CGFloat)alpha;
@end

then in the .m I write this

@implementation UIColor (BIExtras)
+(UIColor *)colorWithR:(CGFloat)red G:(CGFloat)green B:(CGFloat)blue A:(CGFloat)alpha {
return [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:alpha];    
}
@end

then I try to set the desired gradient that I’m after for a particular row.

TaskDisplayCell *cell = (TaskDisplayCell *)[self.tableView dequeueReusableCellWithIdentifier:TaskCellIdentifier];
if (indexPath.row == 0) {
    cell.backgroundView = [[CustomRowBackground alloc]  initWithFrame:CGRectMake(0,0,self.tableView.bounds.size.width,40) 
topStroke:[UIColor colorWithR:119 G:119 B:119 A:1].CGColor 
lightColor:[UIColor colorWithR:92 G:92 B:92 A:1].CGColor 
darkColor:[UIColor colorWithR:70 G:70 B:70 A:1].CGColor 
bottomStroke:[UIColor colorWithR:76 G:76 B:76 A:1].CGColor 
borderColor:[UIColor colorWithR:110 G:110 B:110 A:1].CGColor]; 
}

Note: I am not sure if this is the way to do it. I just want to initialise the background with a different gradient theme.

Anyways, it gives me an error. If I manually write in the drawRect an assignment of a [UIColor colorWith] method, that works. If I instead allow for code reuse, it crashes.

Any ideas?

Ben

Answer 1

One problem I see in your program is that you do not perform memory management of your CGColorRefs — ARC (assuming you have it enabled) does not manage non-ObjC objects for you. You must retain and release these manually. So in both ARC and MRC, you must retain and release these manually.

This is the basic form:

@interface CustomRowBackground : UIView {
    CGColorRef color;
}

- (id)initWithFrame:(CGRect)frame color:(CGColorRef)pColor;

@end

- (id)initWithFrame:(CGRect)frame color:(CGColorRef)pColor
{
    self = [super initWithFrame:frame];
    if (self) {
        color = CGColorRetain(pColor);
    }
    return self;
}

- (void)dealloc
{
    CGColorRelease(color), color = 0;
// [super dealloc]; if MRC
}

- (CGColorRef)color
{
    return color;
}

- (void)setColor:(CGColorRef)p
{
    if (color == p) {
        return;
    }
    CGColorRef prev = color;
    color = CGColorRetain(p);
    CGColorRelease(prev);
}