Question

Okay I am creating a Table View using objective c, but the data source is not working correctly…

My error:

2012-06-02 20:14:39.891 Dot Golf Scoring[195:707] *** Assertion failure in -[UITableView _createPreparedCellForGlobalRow:withIndexPath:], /SourceCache/UIKit/UIKit-1914.85/UITableView.m:6061
2012-06-02 20:14:39.895 Dot Golf Scoring[195:707] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:'

My Code:

-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}

-(NSInteger) tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return 16;
}

-(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    return @"Comments On Your Round";
}

-(UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];

    cell.textLabel.text = @"Text Label";

    return cell;
}

Why is the table view not getting filled with this fake data???

Answer 1

You are never initializing cell. Use this code:

    - (UITableViewCell *)tableView:(UITableView *)tableView2 cellForRowAtIndexPath:(NSIndexPath *)indexPath 

{


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


    if (cell == nil) {

        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault
                                       reuseIdentifier:@"UITableViewCell"]
                autorelease];


        cell.textLabel.text = nil;                


    }

    if (cell) {

        //customization 
        cell.textLabel.text = @"Text Label";
    }

    return cell;
}

You say you are a noob…. let me explain
First of try picking up the book:

The Big Nerd Ranch Guide

What you are thinking is that dequeueing is basically initializing right? NO! Dequeuing is basically nilling any cell that is not visible, aka you scroll past it. Therefore, cell == nil will be called in probably four situations (that I can think of):

1. When we first setup the table view (cells will be nil)
2. When we reload data
3. Whenever we may arrive at this class
4. When the cells becomes invisible from the table view

So, the identifier for dequeuing is like an ID. Then in the statement to see if cell is nil, we initialize cell, you can see the overridden init method: initWithStyle. This is just what type of cell there is, there are different types with different variables you can customize. I showed you the default. Then we use the reuseIdentifier which was the dequeuing identifier we said earlier. THEY MUST MATCH! I nil textLabel just for better structure, in this case each cell has the same text so it won’t matter really. It makes it so the cell that dequeues comes back with the right customization you implemented. Then once cell is actually valid, we can customize.

Also, you are using the same text for each cell. If you do want to have different text for each cell, familiar yourself with NSArray. Then you could provide the array count in numberOfRowsForSection and then do something like this:

cell.textLabel.text = [array objectAtIndex: [indexPath row]];

Where indexPath is the NSIndexPath argument provided in the cellForRowAtIndexPath method. The row variable is the row number, so everything fits!

Wow, that was a lot to take in right!
Now go stop being an objective-c noob and start reading some books!

For more info read:

Table View Apple Documentation