Objective-C Fundamentals

Introducing the Rental Manager application
31
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section {
{
return 25;
}
- (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] autorelease];
}
}
Listing 2.1
cell.textLabel.text = [NSString
stringWithFormat:@"Rental Property %d", indexPath.row];
NSLog(@"Rental Property %d", indexPath.row);
return cell;
Handling UITableView requests for the contents to display in the table
Determine
number of rows
When the Rental Manager application runs, the UITableView control calls your
tableView:numberOfRowsInSection: method to determine how many rows you want
to display B. It then calls tableView:cellForRowAtIndexPath: a number of times as
the user slides up and down the list to obtain the content for each visible row.
Your implementation of tableView:cellForRowAtIndexPath: is made up of two
steps. The first c creates a new table view cell with the UITableViewCell-
StyleDefault style. This style displays a single line of large, bold text (other built-in
styles replicate the layouts found in the settings or iPod music player applications).
The second step d sets that line of text to the string "Rental Property %d", where %d
is replaced with the index position of the current row.
Press Cmd-R to rerun the application and you should see the main view displaying
a list of 25 rental properties. Your challenge in this chapter is to learn how to store
data in your application before expanding your tableView:cellForRowAtIndexPath:
method to display some practical information about each rental property.
Before moving on, take a look at tableView:cellForRowAtIndexPath: and, in particular,
the last line that calls a function named NSLog. Notice that this method takes
arguments similar to those of NSString’s stringWithFormat: method, which generated
the string that was displayed in the table view cells onscreen.
NSLog is a handy function to learn and use. It formats a string but also sends the
result to the Xcode debugger console (see figure 2.3). NSLog can be a useful way to
diagnose the inner workings of your application without relying on breakpoints.
While the Rental Manager application is running, you can view the output from
calls to NSLog by viewing the debugger console (Shift-Cmd-Y), as shown in figure 2.3.
B
c
Create table
view cell
d
Set the line
of text