UIDatePicker in iPhone - iphone

Question

I'm struggling with UIDatePicker. I thought I could add it to my current view just as I would an ordinary subview, but it didn't appear. After some searching, I found documentation for putting it in a popover. I followed those instructions and got it to work on the iPad. But popovers don't work on the iPhone. What do I need to do to make it work there? Why can't I simply add it like a regular subview?
Here's my iPad code:
-(void)selectADate: (CGPoint)p
{
UIViewController* popoverContent = [[UIViewController alloc] init]; //ViewController
UIView *popoverView = [[UIView alloc] init]; //view
popoverView.backgroundColor = [UIColor blackColor];
UIDatePicker *datePicker=[[UIDatePicker alloc]init];//Date picker
datePicker.frame=CGRectMake(0,44,320, 216);
datePicker.datePickerMode = UIDatePickerModeDate;
[datePicker setTag:10];
datePicker.date = self.displayedDate;
[datePicker addTarget:self action:#selector(pickerChanged:) forControlEvents:UIControlEventValueChanged];
[popoverView addSubview:datePicker];
popoverContent.view = popoverView;
UIPopoverController * popoverController = [[UIPopoverController alloc] initWithContentViewController:popoverContent];
//popoverController.delegate=self;
self.datePopover = popoverController;
[popoverController setPopoverContentSize:CGSizeMake(320, 264) animated:NO];
CGRect popoverLocation = CGRectMake(p.x-160, p.y-200, 320, 216);
[popoverController presentPopoverFromRect:popoverLocation inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];//tempButton.frame where you need you can put that frame//
}
- (void)pickerChanged:(id)sender
{
self.displayedDate = [sender date];
[self showMonthContainingDate:[sender date]];
}
My screen is currently laid out as a sort of calendar page showing a month of days. Each day's sell is a subview. At the top of the screen is a header, which has information on the year, month, etc. When the user taps the header, the date picker appears, and the calendar page displays the month selected that corresponds to the date chosen in the picker with the day highlighted (that day's subview's background has a different color).
I'm not sure why I even need a popover, unless it is just to provide a blank view on which to place the date picker that is in front of the tiled views of my calendar page. But then shouldn't I be able to simply add it as a subview and then call bringSubviewToFront:? I tried that, but it didn't work on the iPad, hence my use of the popover.
I can get it to display if I add it when I add the other subviews, but I want it to display when I tap the heading. Here's my tap code:
- (IBAction)tap:(UITapGestureRecognizer *)sender {
//tap gesture recognizer
//Assume the user tapped on a day cell.
for (UIView *dayCell in self.view.subviews) {
if (CGRectContainsPoint(dayCell.frame, [sender locationInView:self.view])) {
//found the cell that was touched.
//NSLog(#"Found a view containing the touch with coords. %#",NSStringFromCGRect(dayCell.frame));
for (UIView *insideView in dayCell.subviews) {
for (UILabel *dayElement in insideView.subviews) {
//found a subview of the day cell.
if ([dayElement isKindOfClass:[UILabel class]]) {
NSLog(#"Found a subview %#",dayElement.text);
}
}
}
}
if ([dayCell isKindOfClass:[UILabel class]]) {
// This is the heading label.
UILabel * headingLabel = (UILabel *) dayCell;
if (CGRectContainsPoint(headingLabel.frame, [sender locationInView:self.view])) {
NSLog(#"The heading was tapped");
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
//iPhone code goes here
[self iphoneSelectADate:[sender locationInView:self.view]];
} else {
[self selectADate:[sender locationInView:self.view]];
}
}
}
}
}
Here is the currently nonworking iPhone code:
-(void)iphoneSelectADate: (CGPoint)p
{
UIDatePicker *datePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, self.view.bounds.size.height - 216, 320, 216)];
[datePicker setDate:[NSDate date]]; //This is the default
[datePicker setHidden:NO];
[self.view addSubview:datePicker];
}
If I step through in the debugger, I see this code is executed, but the datepicker does not display.

Answer 1

UIDatePicker inherits from UIView, so you can add it just like a UILabel. Make sure you give it a frame.
Something like this would work for the bottom of an iPhone screen:
datePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, self.view.bounds.size.height - 216, 320, 216)];
[datePicker setDate:[NSDate date]]; //This is the default
[self.view addSubview:datePicker];
It sounds like you likely have a subview layering issue, not a UIDatePicker issue though.
If that doesn't work, post some of your code and we'll help figure it out.

Answer 2

Not sure if this will help, but UI changes for views that are already present require to be dispatched using the main_queue
for e.g.
dispatch_async(dispatch_get_main_queue(), ^
{
[self.view addSubview:yourSubview];
});

Answer 3

I think I may have found the key to my problem. After reading through this document on the various places to place orientation-related code, I decided on viewWillLayoutSubviews. I read through the document again and decided to try putting that code in viewWillAppear instead, and that seems to have resolved the problem.
The change to using viewWillAppear also required implementation of willAnimateRotationToInterfaceOrientation:duration:
It looks like viewWIllLayoutSubviews is needed for iPad but not iPhone, so I've also added this:
-(void)viewWillLayoutSubviews
{
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
//iPhone code goes here (empty, since calling showMonthContainingDate: doesn't work from here in iPhone
} else {
//ipad code goes here
NSDate *dayToDisplay = self.displayedDate;
[self showMonthContainingDate:dayToDisplay];
//iPad uses wrong dimensions unless the routine is called from here.
}
}
One final note. There is one scenario where the orientation of the device is not set correctly -- that is landscape on an iPhone at launch. According to this answer to another question the iPhone always launches in portrait unless it is a landscape-only app.