Sometimes Xcode does a bit of magic behind the scenes which I don’t really understand. Consider this standard table view method to display cells: – (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@”Cell”]; // populate your cell return cell; } Where do we actually ever create a UITableViewCell? All we’re asking here […]
If you add a UISearchBar to your table view (see previous article) it’s just sitting there by default. Chances are you’d like to hide it when your table view first loads. You can do this by adding the following code to your viewWillAppear method: – (void)viewWillAppear:(BOOL)animated { // scroll the search bar off-screen CGRect newBounds […]
The ingredients for a search function in a UITableView are more involved than just displaying a simple search field. First we need the standard UITableView. Next we need a UISearchBar which can be added to the top of the table view. But displaying the actual search results is something called the UISearchDisplayController. This process isn’t […]
It has happened to us all: you’re in a storyboard, you’re using the Assistant Editor, you want to control-drag from a button into your code and create an action. But sadly you forget to select “Action” from the drop down menu and instead create an outlet. No biggie you think, deleting the outlet code. You […]
Imagine you had an NSString and wanted to save it as an integer value. You can use the intValue method for that: NSString *myString = @”47″; int myInt = [myString intValue]; To do the reverse, you can use the initWithFormat method: int myInt = 32; NSString *myOtherString = [[NSString alloc]initWithFormat:@”%i”, myInt];
We can use something called Fast Enumeration for this, using a modified for loop: // build an array NSArray *myArray = [[NSArray alloc]initWithObjects:@”One”, @”Two”, @”Three”, @”Four”, nil]; // loop through every element (dynamic typing) for (id tempObject in myArray) { NSLog(@”Single element: %@”, tempObject); } You don’t have to use dynamic typing if you know […]
We can use the C function rand() for this: int i = rand()%10+1; NSLog(@”Random Number: %i”, i); This generates an integer between 1 and 10. Alternatively you can use the arc4random function: int i = arc4random() % 10; NSLog(@”Random Number: %i”, i); This will generate a random number between 0 and 9. One thing of […]
Imagine we had a file called myfile.txt which is a standard text file. On each line we have a new item we’d like to read so that our app can do something with it. Here’s how we do that: // get a reference to our file NSString *myPath = [[NSBundle mainBundle]pathForResource:@”myfile” ofType:@”txt”]; // read the […]
