Understanding the Issue with UITableView in iOS Applications

As developers, we have all encountered situations where our table view is not displaying as expected. In this article, we will delve into a specific issue that was reported on Stack Overflow regarding UITableView in an iOS application. We will explore the problem, analyze the code provided, and find a solution to display the UITableView correctly.

The Problem

The developer, who posted on Stack Overflow, was experiencing issues with their UITableView not displaying correctly when using a UINavigationController as the root view controller. Despite creating a TaskRootController class that inherits from UIViewController (UITableViewDelegate) and adds a UITableView as its view, only the title of the controller and background color were visible.

However, if the application started with TaskRootController as the rootViewController, the table view was displayed correctly.

Understanding Table View Configuration

To solve this issue, we need to understand how UITableView is configured in an iOS application. A UITableViewCell can be reused by setting its reuseIdentifier property to a unique identifier for each type of cell. When a new cell needs to be created or updated, the dequeueReusableCell method is called with the reuse identifier.

We also need to set up our table view’s delegate and data source to handle cell selection events and provide data for the cells.

Analyzing the Code

Now that we understand the basics of UITableView configuration, let’s analyze the provided code. The TaskController class has a taskRootController property initialized in its initWithNibName method. However, this initialization is not sufficient to display the table view correctly.

In addition, the TaskRootController class has a taskRootView property initialized in its viewDidLoad method. This is where the problem lies. The table view’s frame is set based on the size of the self.view bounds, but this does not necessarily mean that it will be displayed correctly within the navigation controller.

Solution

To display the UITableView correctly, we need to adjust the TaskRootController class to properly configure its table view and handle cell selection events.

TaskController.m

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.taskController = [[TaskController alloc] init];
    UIViewController *root = self.taskController;
    [self initWithRootViewController: root];
}

TaskRootController.m

@implementation TaskRootController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    NSLog(@"DUPA");

    NSLog(@"SIZE x:%f,y:%f ; %f:%f", self.view.bounds.origin.x, self.view.bounds.origin.y, self.view.bounds.size.width, self.view.bounds.size.height);
    self.view.backgroundColor = [UIColor grayColor];
    self.title = @"Root";

    // Configure table view
    UITableView *tableView = [[UITableView alloc] initWithFrame: CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height) style:UITableViewStyleGrouped];
    tableView.delegate = self;
    tableView.dataSource = self;
    [self.view addSubview:tableView];

}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    // Return the number of sections.
    return 1; // put number for section.
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    return 6; // put number as you want row in section.
}

- (CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    CGFloat result = 20.0f;
    if([tableView isEqual:self.taskRootView])
    {
        result = 40.0f;
    }
    return result;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }
    cell.textLabel.text = @"this is row";

    return cell;
}

@end

TaskController.h

#import <UIKit/UIKit.h>

@interface TaskController : UIViewController <UITableViewDataSource, UITableViewDelegate>

@property (nonatomic, strong) TaskRootController *taskRootController;

@end

In this solution, the task controller’s delegate and data source are set to itself in its viewDidLoad method. The table view is configured with a unique identifier for each type of cell.

By making these changes, we should now be able to display the UITableView correctly within our navigation controller.

Conclusion

Displaying a UITableView in an iOS application can sometimes be tricky, especially when working with nested controllers and navigating between them. By understanding how table views are configured and setting up our delegate and data source properly, we can ensure that our table view is displayed as expected.

In this article, we have analyzed the problem presented on Stack Overflow regarding a UITableView not displaying correctly in an iOS application using a UINavigationController as the root view controller. We have also provided a solution by adjusting the TaskRootController class to properly configure its table view and handle cell selection events.

Additional Resources

For further learning about iOS development, including table views and navigation controllers, I recommend checking out Apple’s official documentation and tutorials. Additionally, there are many online resources available that provide detailed explanations and examples of various iOS development topics.

Last modified on 2023-09-22