Question

I have the following code in my didSelectRowAtIndexPath delegate method:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    Exercise *exerciseView = [[Exercise alloc] initWithNibName:@"Exercise" bundle:nil]; //Makes new exercise object.

    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    NSString *str = cell.textLabel.text; // Retrieves the string of the selected cell.

    exerciseView.exerciseName.text = str;

    NSLog(@"%@",exerciseView.exerciseName.text);

    [self presentModalViewController:exerciseView animated:YES];
}

In this, I try to take the text of the selected cell, and set the IBOutlet UILabel exerciseName to that string.

My method compiles, but when I run the NSLog, which prints the textvalue of the UILabel after setting it to str, it returns null. I feel like this is a pointer problem, but can’t seem to grasp it. Can anyone clarify things?

Answer 1

The problem is the half-initialized view controller. Need to let it get built before you init the contents of a subview.

Exercise.h

@property(strong, nonatomic) NSString *theExerciseName;  // assuming ARC

- (id)initWithExerciseName:(NSString *)theExerciseName;

Exercise.m

@synthesize theExerciseName=_theExerciseName;

- (id)initWithExerciseName:(NSString *)theExerciseName {

    self = [self initWithNibName:@"Exercise" bundle:nil];
    if (self) {
        self.theExerciseName = theExerciseName;
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    exerciseName.text = self.theExerciseName;
}

Call that new initializer from your didSelect method.

Exercise *exerciseView = [[Exercise alloc] initWithExerciseName:str]; 

But please get that str by using the logic within cellForRowAtIndexPath, not by calling it.