iPhone UIViewController不显示从第一个视图控制器传递的数据

Question

The purpose of this app is to retrieve the data selected on UITableCell and pass that on to a new view controller. All is well until the user selects the cell. The next view controller is loaded but the screen is black. On that screen i have a UIImageView and UILabel . I have a UINavigationController set up in the storyboard. I am trying to get the image and text selected on the first screen to the respective objects on the next screen. I have retrieved the data from a database and have loaded it to the first screen.

Here is my code on my storedetail.h which is a subclass to a UIViewController ,

@property (nonatomic, copy) UIImage *storeImage;
@property (nonatomic, copy) UILabel *storeCode;

Here is my code where i am calling the nextviewcontroller which is ShowStores.m which is a subclass of a UITableView ,

header code ,

#import "ShowStores.h"
#import "StoreDetail.h"

code where i load the next view when the user selects the cell,

(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
[tableView deselectRowAtIndexPath:indexPath animated:NO];
StoreDetail *storedetail = [[StoreDetail alloc] init];
storedetail.storeImage = cell.imageView.image;
storedetail.storeCode = cell.textLabel;
storedetail.storeCode.text = cell.textLabel.text;
[self.navigationController pushViewController:storedetail animated:YES];
}

I have debugged it and the cell.textLabel.text and cell.imageView.image are not nil or null. The second view loads but is black. I have set up a back button on the second view which takes the user back to the first view and that works fine.

Answer 1

UIImage and UILabel don't conform to NSCopying protocol, that's most probably the reason. And so declaring @property (nonatomic, copy) doesn't do any effect as your intention.

My suggestion is setting retain for them, and at the point where you want to make copies, just initialize and assign the objects to them.

Answer 2

do you have a nib for your second view controller with the storeCode uiLabel in? or are you creating the storeCode UILabel programmatically in viewDidLoad?

I would remove this line:

   storedetail.storeCode = cell.textLabel;

in this line:

   storedetail.storeImage = cell.imageView.image;

storeImage is a UIImage when I think you want it to be a UIImageView. (I would remove that line too and create a storeImageView the same way as you create the storeCode uiLabel - either have it in your nib or create it programmatically in viewDidLoad.

EDIT:

create the objects in viewDidLoad as follows:

storeCode = [[UILabel alloc] initWithFrame:CGRectMake(10, 20, 120, 16)];
[self addSubview:storeCode];

For the image I would set the name of the image (filename or path) to an NSString property on your second view controller and then in viewWillAppear use the string to create the correct UIImage and then assign that UIImage to your UIImageView.