HTAutocompleteTextField is a subclass of UITextField that automatically displays text suggestions in real-time. This is perfect for automatically suggesting the domain as a user types an email address.

You can see it in action in the animated gif below or on Youtube, or read about it in the accompanying blog post on the HotelTonight Engineering Blog:

• HTAutocompleteTextField.m
• HTAutocompleteTextField.h
• HTAutocompleteManager.m and HTAutocompleteManager.h

• Add pod 'HTAutocompleteTextField' to your Podfile
• Manually add HTAutocompleteManager.m and HTAutocompleteManager.h to your project (these files are not part of the pod, as you will probably want to customize them)

Create an HTAutocompleteTextField instance exactly as as you would UITextField. You can do eith either programmitcally or in Interface Builder. Programmatically, this looks like:

HTAutocompleteTextField *textField = [[HTAutocompleteTextField alloc] initWithFrame:CGRectMake(0,0,100,31)];

The data source is the brains of the autocomplete logic. If you just want to autocomplete email addresses, use HTAutocompleteManager from the example project as follows:

textField.autocompleteDataSource = [HTAutocompleteManager sharedManager];
textField.autocompleteType = HTAutocompleteTypeEmail;

HTAutocompleteManager (included in the example project) provides email address autocompletion out of the box. It comes with a list of the top email domains based on the HotelTonight customer database. You may want to tailor this list of email domains to match your own customers, or you may want to write autocomplete logic for a different type of text field (in the demo, names of colors are autocompleted).

Alternatively, you may wish to create your own data source class and user the autocompleteType property to differentiate between fields with different data types. A HTAutocompleteTextFields's data source must implement the following method, as part of the HTAutocompleteDataSource protocol.

- (NSString *)textField:(HTAutocompleteTextField *)textField completionForPrefix:(NSString *)prefix ignoreCase:(BOOL)ignoreCase

You may also set a default dataSource for all instances of HTAutocompleteTextField. In the example project, we use a HTAutocompleteManager singleton:

 [autocompleteTextOffset setDefaultAutocompleteDataSource:[HTAutocompleteManager sharedManager]];

To adjust the position of the autocomplete label by a fixed amount, set autocompleteTextOffset:

textField.autocompleteTextOffset = CGPointMake(10.0, 10.0);

For more dynamic positioning of the autocomplete label, subclass HTAutocompleteTextField and override - (CGRect)autocompleteRectForBounds:(CGRect)bounds.

To adjust the properties (i.e. font, textColor) of the autocomplete label, do so via the `[AutocompleteTextField autocompleteLabel] property.

textField.autocompleteLabel.textColor = [UIColor grayColor];

In addition to observing the standard UITextField notifications (i.e. UITextFieldTextDidChangeNotification and friends), you can use [HTAutocompleteTextField autoCompleteTextFieldDelegate] to listen for certain events. This is particularly useful if you are collecting analytics.

• Use this in your apps whenever you can, particularly email addresses -- your users will appreciate it!
• Contributions are very welcome.
• Attribution is appreciated (let's spread the word!), but not mandatory.

Tweet the author @jonsibs, and check out HotelTonight's engineering blog: http://engineering.hoteltonight.com

Also, check out HotelTonight's other iOS open source:

• https://github.com/hoteltonight/HTAutocompleteTextField
• https://github.com/hoteltonight/HTGradientEasing
• https://github.com/hoteltonight/HTStateAwareRasterImageView
• https://github.com/hoteltonight/HTDelegateProxy