UICollectionview is not working, I am not getting any Cell

Question

I am trying to use a collection view and reuse a collection view cell and I have to get 23 images and name from server which I have not started coz of the problem I am facing

This is my custom cell file collection view file objective c

Below is my custom cell.h

#import <UIKit/UIKit.h>

@interface CustomCell : UICollectionViewCell

{
    UIImageView *imageView;
}

@property (nonatomic, retain) UIImageView *imageView; //this imageview   is the only thing we need right now.


@end

Here is my custom cell.m file

#import "CustomCell.h"

@implementation CustomCell

@synthesize imageView;

- (id)initWithFrame:(CGRect)aRect
{
    if (self = [super initWithFrame:aRect])
    {
    //we create the UIImageView in this overwritten init so that we always have it at hand.
    imageView = [[UIImageView alloc] init];
    //set specs and special wants for the imageView here.
    [self addSubview:imageView]; //the only place we want to do this addSubview: is here!

    //You wanted the imageView to react to touches and gestures. We can do that here too.
    UITapGestureRecognizer * tap=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onButtonTapped:)];
    [tap setNumberOfTapsRequired:1];
    [self addGestureRecognizer:tap];


    //We can also prepare views with additional contents here!
    //just add more labels/views/whatever you want.
    }
    return self;
    }

    -(void)onButtonTapped:(id)sender
    {
     //the response to the gesture.
     //mind that this is done in the cell. If you don't want things to happen from this cell.
     //then you can still activate this the way you did in your question.  
     }
 @end

These are the methods in my normal view controller.m file

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cvCell" forIndexPath:indexPath];

    [[[cell contentView] subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];


    // create a uiview where we can place all views that need to go into this cell
    UIView * contents=[[UIView alloc]      initWithFrame:cell.contentView.bounds];
    [contents setBackgroundColor:[UIColor clearColor]];
    [cell.contentView addSubview:contents];


    // set tag to the indexPath.row so we can access it later
    [cell setTag:indexPath.row];

    // add interactivity
    UITapGestureRecognizer * tap=[[UITapGestureRecognizer alloc]  initWithTarget:self action:@selector(onButtonTapped:)];
    [tap setNumberOfTapsRequired:1];
    [cell addGestureRecognizer:tap];


if (cell.selected) {
    cell.backgroundColor = [UIColor blueColor]; // highlight selection
}
else
{
    cell.backgroundColor = [UIColor redColor]; // Default color
}
return cell;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath  {

    UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
    datasetCell.backgroundColor = [UIColor blueColor]; // highlight selection
}

-(void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath {

UICollectionViewCell *datasetCell =[collectionView cellForItemAtIndexPath:indexPath];
datasetCell.backgroundColor = [UIColor redColor]; // Default color
}

I don't get any cell when I moved to this view, it is just blank with the background image and I have even given a blank picture to see how the view is but I don't get anything please help!!!

@AravindAR it shud be given to the view controller where I use collection view rite?? — Akshay, Jun 12 '17 at 06:42
but I dont see a image view or uilabel which I had in the cell — Akshay, Jun 12 '17 at 06:43
Add this line of code in viewDidLoad [collectionView registerClass:[CustomViewCell class] forCellWithReuseIdentifier:@"CustomIdentifier"]; and CustomViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CustomIdentifier" forIndexPath:indexPath]; this in cellForItemAtindexPath — Developer, Jun 12 '17 at 06:44
@coder I am getting error no known method in the current class visible — Akshay, Jun 12 '17 at 06:46
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath Replace the blow line of code UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cvCell" forIndexPath:indexPath]; — Developer, Jun 12 '17 at 06:48
[UICollectionView registerClass:[CustomCell class] forCellWithReuseIdentifier:@"CustomIdentifier"]; this line is giving me error when I used it in view did oad — Akshay, Jun 12 '17 at 06:52
@Akshay Are you adding cells to the collection view from xib or are you using storyboard ? — Aravind A R, Jun 12 '17 at 06:58
Then you don't need to use UICollectionView registerClass. You are now able to see the cells right, only thing missing is imageview ? Are you giving color to imageview or are you setting any default image to image view? — Aravind A R, Jun 12 '17 at 07:01
Then you don't have to add imageView = [[UIImageView alloc] init]; [self addSubview:imageView]; [[[cell contentView] subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)]; // create a uiview where we can place all views that need to go into this cell UIView * contents=[[UIView alloc] initWithFrame:cell.contentView.bounds]; [contents setBackgroundColor:[UIColor clearColor]]; [cell.contentView addSubview:contents]; — Aravind A R, Jun 12 '17 at 07:07
@AravindAR I shud add this in uicollectionviewcell method rite?? — Akshay, Jun 12 '17 at 07:09
I am getting use of undeclared identifier error for imageView — Akshay, Jun 12 '17 at 07:12
@Akshay Since there are few changes I have mentioned all the changes in the answer that I have added. — Aravind A R, Jun 12 '17 at 07:24

score 1 · Accepted Answer · answered Jun 12 '17 at 07:16

1

The cells are not displaying because you might not have set the datasource and delegate properly. Since you have added the cells in storyboard you don't need to add the imageview as subview in the collection view cell. First connect the outlet of imageview that you have added in storyboard to the CustomCell. Then remove

{
    UIImageView *imageView;
}

@property (nonatomic, retain) UIImageView *imageView;

You can remove - (id)initWithFrame:(CGRect)aRect this method and you can add the tap gesture initialization in awakeFromNib method

-(void)awakeFromNib {
  UITapGestureRecognizer * tap=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onButtonTapped:)];
    [tap setNumberOfTapsRequired:1];
    [self addGestureRecognizer:tap];
}

No need to do

 imageView = [[UIImageView alloc] init];
    [self addSubview:imageView];

Again in cellForItemAtIndexPath remove the following lines

[[[cell contentView] subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];
UIView * contents=[[UIView alloc]      initWithFrame:cell.contentView.bounds];
[contents setBackgroundColor:[UIColor clearColor]];
[cell.contentView addSubview:contents];

After making these changes please try again

answered Jun 12 '17 at 07:16

Aravind A R

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it is giving outlet cannot be connected for repeating content wen I created a outlet to the view controller or should I connect it to custom cell files?? – Akshay Jun 12 '17 at 07:24
Yup you need to connect outlet to the custom cell – Aravind A R Jun 12 '17 at 07:25
I cannot drag it as the cell is of another view controller! how to create outlet in the file??? – Akshay Jun 12 '17 at 07:27
no I am not able to give outlet connection to custom cell.h r customcell.m file – Akshay Jun 12 '17 at 07:32
Have you specified the class of the cell that you have added in storyboard as CustomCell ?? – Aravind A R Jun 12 '17 at 07:33
sorry I did it jus now but sill I dont see the default pic I have set for the image view – Akshay Jun 12 '17 at 07:37
Please upload the screenshot of the storyboard highlighting the custom cell – Aravind A R Jun 12 '17 at 08:31
Please refer to this https://www.ralfebert.de/tutorials/ios-swift-uitableviewcontroller/custom-cells/ – Aravind A R Jun 12 '17 at 08:36
do u have any objective c references?? – Akshay Jun 12 '17 at 08:47
Oops I missed out http://www.theappguruz.com/blog/customize-table-view-cells-uitableview-ios – Aravind A R Jun 12 '17 at 08:56
shud custom cell have a view controller??I am using only one view controller and custom cell is jus controller view files – Akshay Jun 12 '17 at 10:22
@Akshay Your custom cell should be a sub class of UICollectionViewCell – Aravind A R Jun 13 '17 at 05:53
@arvindkr yes it is – Akshay Jun 13 '17 at 05:56

UICollectionview is not working, I am not getting any Cell

1 Answers1