iOS 5故事板自定义单元崩溃：UITableView dataSource必须返回单元

Question

This is either an XCode bug, or me missing a crucial rule here.

Update: - What's the chance of this being a weird bug in XCode/Storyboard?

Situation:

• iOS 5, Storyboard
• This is the storyboard setup: http://i.imgur.com/T5WyD.png
• Another screenshot of the full setup: http://i.imgur.com/1tVuz.png
• TableViewController with Custom Cell, cell has reusable identifier "NewCell"

• in "cellForRowAtIndexPath" I basically have:

  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"NewCell"]; return cell;

• This throws an exception:

  Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:'

Things I have already tried:

• I setup a new project from scratch, TabBarController, with a TableViewController and a Custom Cell, all wired up in Storyboard, set a reusable cell identifier. Used the same code as above, worked perfectly . I don't know why it didn't work with the storyboard above...

I have a feeling it has something to do with the tree I built there, which is a TabBarController, loading a NavigationController, loading a TableViewController, providing a few items, one is clicked, which loads another TableViewController, which is unable to work with the custom cell, somehow.

Important: - The issue is that the Storyboard should make sure that: UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"NewCell"]; will never return NIL (unlike without the Storyboard/iOS4). But, mine is nil. And I can't, for the hell of it, figure out what's happening.

Answer 1

Heyo, I just had this problem today and figured out a few possible causes. To link a UITableView as a subview of a ViewController in Story board check that you have done these steps.

1. In your "ViewController.h", add <UITableViewDataSource> to your list of protocols

   @interface ViewController : UIViewController <UITableViewDataSource>

   you might want to add <UITableViewDelegate> as well but I didn't.

2. In your "ViewController.m" set up your Table view data source functions

    #pragma mark - Table view data source \n\n
    - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { // Return the number of sections. return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { // Return the number of rows in the section. return [yourCells count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NewCell *cell = (NewCell *)[tableView dequeueReusableCellWithIdentifier:@"NewCell"]; if (cell == nil) { NSLog(@"Cell is NIL"); cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier]; } return cell; 
   \n\n} \n\n

3. In Storyboard, connect the UITableView's "Data Source" and "Delegate" references to the ViewController.

4. In Storyboard, give the Prototype Cell the Identifier "NewCell"

If these are done, I believe it should work.

Hope this helps =)

Answer 2

I always use custom cells in the storyboard like this:

static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }
return cell;

Make sure the number of rows/sections is at least one. And another thing to check is that you set the UITableViewController to your custom class name in the storyboard.

Answer 3

回答这个问题可能为时已晚，但我敢打赌， 这将解决您的所有问题

Answer 4

• Did you double check the cell prototype identifier is "NewCell"?
• Your setup as Tabbar->navigationcontroller->tableview is perfectly fine. I am using this layout all the time.
• verify also there's no useless runtime attributes anywhere in this
  viewcontroller/tableview/cell.
• your prototype looks a bit weird there - you added a UIButton to the cell as subview? why?

Answer 5

To solve this problem add the following just above your dequeueReusableCellWithIdentifier statement:

static NSString *CellIdentifier = @"NewCell";

making sure the identifier matches the prototype cell in Storyboard