How to design an iOS program with custom inputViews - iphone

Question

Note, this is a DESIGN question, NOT a functionality question. I already know how to implement the following, I'm just trying to figure out the best way to design it.
I have an iOS app where a few UIViewControllers throughout the app have UITextFields with UIDatePicker input views. The code for this is below:
- (void) viewDidLoad
{
self.dateField.inputView = [self createDatePicker];
}
- (UIView *) createDatePicker
{
UIView *pickerView = [[UIView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height, self.view.frame.size.width, TOOLBAR_HEIGHT + KEYBOARD_HEIGHT)];
UIDatePicker *picker = [[UIDatePicker alloc] init];
[picker sizeToFit];
picker.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
picker.datePickerMode = UIDatePickerModeDate;
[picker addTarget:self action:#selector(updateDateField:) forControlEvents:UIControlEventValueChanged];
[pickerView addSubview:picker];
// Create done button
UIToolbar* toolBar = [[UIToolbar alloc] init];
toolBar.barStyle = UIBarStyleBlackTranslucent;
toolBar.translucent = YES;
toolBar.tintColor = nil;
[toolBar sizeToFit];
UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
UIBarButtonItem* doneButton = [[UIBarButtonItem alloc] initWithTitle:#"Done"
style:UIBarButtonItemStyleDone target:self
action:#selector(doneUsingPicker)];
[toolBar setItems:[NSArray arrayWithObjects:flexibleSpace, doneButton, nil]];
[pickerView addSubview:toolBar];
picker.frame = CGRectMake(0, toolBar.frame.size.height, self.view.frame.size.width, pickerView.frame.size.height - TOOLBAR_HEIGHT);
toolBar.frame = CGRectMake(0, 0, self.view.frame.size.width, TOOLBAR_HEIGHT);
return pickerView;
}
- (void) doneUsingPicker
{
[self.dateField resignFirstResponder];
}
- (void) updateDateField: (UIDatePicker *) datePicker
{
self.dateField.text = [self.formatter stringFromDate:datePicker.date];
}
The problem is, I keep on having to paste this code throughout the app in different classes that have UITextFields with UIDatePicker inputviews. What would be the best way to design this so as to minimize duplicated code. I've thought about having a UIDatePickerableViewController superclass that contains this code, but this doesn't seem extensible. For instance, what if I soon have other types of input views that could be attached to text fields. How should I design this?

Answer 1

You can refactor code/methods shared between the classes in a common superclass, and inherit subclasses inside which you only modify the parts that are needed to be different.
Or, if you approach the problem from a different point of view: create a custom InputWiewWithDatePicker class and move the (self-)configuration and -initialization code inside the - init method of that class. This way you don't have to paste all this everywhere, and only a single line will be duplicated:
customControl = [[InputViewWithDatePicker alloc] init];

Answer 2

My first thought would be to create a new UIView subclass that contains a date picker and text field with the layout you desire. This can be done with a nib or in code. Anyplace you want to add this new kind of view, it's either a one-liner in viewDidLoad, or paint a UIView into a nib and change it's class to your new view class.

Answer 3

Subclass your desired layout, then when you allocate it, it will come with all the options you have defined.