Passing a value from a class to a cell - ios

Question

In my app I'm using the PSCollectionView to create a view similar to pinterest. Now I'm trying to pass from my class to the cell class a value in which I insert the height of the imageView I set in the cell. When I run the app, the app create a cell exactly using this height, but the imageView has no dimension.
I post here my code:
PSCollectionView controller
- (CGFloat)collectionView:(PSCollectionView *)collectionView heightForRowAtIndex:(NSInteger)index {
NSString *width = [self.arrayWithData[index] objectForKey:#"width"];
NSString *height = [self.arrayWithData[index] objectForKey:#"height"];
NSLog(#"%# e %#", width, height);
cellHeight = [self getHeightWith:width andHeight:height];
return cellHeight;
}
- (CGFloat)getHeightWith:(NSString *)originalWidth andHeight:(NSString *)originalHeight {
float width = [originalWidth floatValue];
float height = [originalHeight floatValue];
float multiplier = height / width;
// So che la mia cella ha una dimensione massima in larghezza di 100, da questo calcolo l'altezza
return 100 * multiplier;
}
- (PSCollectionViewCell *)collectionView:(PSCollectionView *)collectionView cellForRowAtIndex:(NSInteger)index {
ProductViewCell *cell = (ProductViewCell *)[self.psView dequeueReusableViewForClass:nil];
if (!cell) {
//cell = [[ProductViewCell alloc]initWithFrame:CGRectMake(10, 70, 100, 100)];
//cell = [[ProductViewCell alloc] initWithFrame:CGRectMake(0,0,collectionView.frame.size.width/2,100)];
cell = [[ProductViewCell alloc] initWithFrame:CGRectMake(0,0,collectionView.frame.size.width/2,cellHeight + 20)];
}
cell.imageHeight = cellHeight;
cell.labelName.text = [[self.arrayWithData objectAtIndex:index]objectForKey:#"name"];
NSURL * url = [NSURL URLWithString:[[self.arrayWithData objectAtIndex:index]objectForKey:#"url"]];
[self loadImageFromWeb:url andImageView:cell.productImage];
return cell;
}
- (void) loadImageFromWeb:(NSURL *)urlImg andImageView:(UIImageView *)imageView {
//NSURLRequest* request = [NSURLRequest requestWithURL:url];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:urlImg];
NSString *authCredentials =#"reply:reply";
NSString *authValue = [NSString stringWithFormat:#"Basic %#",[authCredentials base64EncodedStringWithWrapWidth:0]];
[request setValue:authValue forHTTPHeaderField:#"Authorization"];
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse * response,
NSData * data,
NSError * error) {
if (!error){
UIImage *image = [[UIImage alloc] initWithData:data];
[imageView setImage:image];
[HUD hide:YES];
} else {
NSLog(#"ERRORE: %#", error);
}
}];
}
and this code:
ProductViewCell.h
#import "PSCollectionViewCell.h"
#interface ProductViewCell : PSCollectionViewCell {
float wMargin;
}
#property(nonatomic,strong)UIImageView *productImage;
#property(nonatomic,strong)UILabel *labelName;
// I use this variable to pass the height of the cell from the class who implement PSCollectionView
#property CGFloat imageHeight;
+ (CGFloat)heightForViewWithObject:(id)object inColumnWidth:(CGFloat)cloumnWidth;
#end
ProductViewCell.m
#import "ProductViewCell.h"
#define MARGIN 8.0
#implementation ProductViewCell
- (id)initWithFrame:(CGRect)frame
{
wMargin = 5.0;
self = [super initWithFrame:frame];
if (self) {
// self.productImage = [[UIImageView alloc]initWithFrame:CGRectMake(wMargin, 5, frame.size.width - (wMargin * 2), 125)];
self.productImage = [[UIImageView alloc]initWithFrame:CGRectMake(wMargin, 5, frame.size.width - (wMargin * 2), self.imageHeight)];
self.labelName = [[UILabel alloc]initWithFrame:CGRectMake(wMargin, 130, frame.size.width - (wMargin * 2), 20)];
self.labelName.font = [self.labelName.font fontWithSize:12];
self.labelName.textAlignment = NSTextAlignmentCenter;
[self addSubview:self.productImage];
[self addSubview:self.labelName];
self.backgroundColor = [UIColor colorWithRed:236.0f/255.0f green:236.0f/255.0f blue:236.0f/255.0f alpha:1.0];
self.layer.masksToBounds = YES;
self.layer.borderWidth = 1.0f;
self.layer.cornerRadius = 10.0f;
self.layer.borderColor= [[UIColor colorWithRed:207.0f/255.0f green:207.0f/255.0f blue:207.0f/255.0f alpha:1] CGColor];
[self.productImage setContentMode:UIViewContentModeScaleAspectFit];
}
return self;
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
#end
When I try to log the value of self.imageHeight it shows in the console a 0, but you can see that I set this data to cellHeight in the PSCollectionView controller.
How I can send the data I calculate to my cell? There's a way to do that?

Answer 1

According to the provided code, the class property imageHeight in the ProductViewCell implementation is only used when a new cell is initialized. At that time the imageHeight has never been set or updated, so it will always be 0.
This means whenever you update the value for imageHeight, the cell property will be updated, but the cell won't do anything with it.
To achieve that you can simply override the setImageHeight: method in ProductViewCell to be able to trigger some action.
- (void)setImageHeight:(CGFloat)imageHeight {
if (_imageHeight != imageHeight) {
_imageHeight = imageHeight;
// Do something useful with the new value e.g. calculations
}
}
This method will be called every time you update the cell property
cell.imageHeight = ...

Answer 2

Finally I did it without using setter! The solution is simply to use the frame.size.height. My cell code is the following:
- (id)initWithFrame:(CGRect)frame
{
wMargin = 5.0;
self = [super initWithFrame:frame];
if (self) {
self.productImage = [[UIImageView alloc]initWithFrame:CGRectMake(wMargin, 5, frame.size.width - (wMargin * 2), frame.size.height)];
self.labelName = [[UILabel alloc]initWithFrame:CGRectMake(wMargin, frame.size.height, frame.size.width - (wMargin * 2), 20)];
self.labelName.font = [self.labelName.font fontWithSize:12];
self.labelName.textAlignment = NSTextAlignmentCenter;
[self addSubview:self.productImage];
[self addSubview:self.labelName];
self.backgroundColor = [UIColor colorWithRed:236.0f/255.0f green:236.0f/255.0f blue:236.0f/255.0f alpha:1.0];
self.layer.masksToBounds = YES;
self.layer.borderWidth = 1.0f;
self.layer.cornerRadius = 10.0f;
self.layer.borderColor= [[UIColor colorWithRed:207.0f/255.0f green:207.0f/255.0f blue:207.0f/255.0f alpha:1] CGColor];
[self.productImage setContentMode:UIViewContentModeScaleAspectFit];
}
return self;
}
I simply used the frame.size.height to define the height of my imageView and following you can see the result: