Note: You don't have to check up the library to understand the question, I just brought it up for reference.
I implemented DIDatePicker in xcode. The way I inserted it in a view is: I inserted a UIView to the viewController with auto-layout, then at the Identity inspector I set the class to DIDatepicker.
The problem is, DIDatepicker doesn't resize to the view's size. I was thinking a possible solution may be, to set DIDatePicker as the view's class in viewDidLoad, though I don't know how to do that.
My question is: if my theory is right, how can I set DIDatePicker as the view's class. If what I said is not true, how can I make DIDatePicker to resize with the view?
DIDatePicker has a collectionView; here is how it's defined:
UICollectionViewFlowLayout *collectionViewLayout = [[UICollectionViewFlowLayout alloc] init];
[collectionViewLayout setItemSize:CGSizeMake(kDIDatepickerItemWidth, CGRectGetHeight(self.bounds))];
[collectionViewLayout setSectionInset:UIEdgeInsetsMake(0, kDIDatepickerSpaceBetweenItems, 0, kDIDatepickerSpaceBetweenItems)];
[collectionViewLayout setMinimumLineSpacing:kDIDatepickerSpaceBetweenItems];
_datesCollectionView = [[UICollectionView alloc] initWithFrame:self.bounds collectionViewLayout:collectionViewLayout];
so I had the same exact problem as you.
The problem is that when you build DIDatepicker it builds its own collection view based on the view's original frame rather than the frame after auto-layout takes place.
The way to circumvent this problem is by not making the storyboard UIView of class DIDatepicker. Instead, just use a normal UIView and then create a DIDatepicker instance with the same frame as the UIView in the ViewDidLoad Method.
Here is an example. datePickerView is the UIView from the storyboard.
datepicker = DIDatepicker(frame: CGRectMake(datePickerView.frame.origin.x, datePickerView.frame.origin.y , self.view.frame.width, datePickerView.frame.height));
self.view.addSubview(datepicker!);
If that doesn't work try changing the frame and adding it to the datePickerView as a subview instead of the main view.
Hope this helps!
I'm not totally sure if your "theory" about setting the main view to DIDatepicker is correct, but you should be able to test it by selecting the default "View" that is in the View Controller and setting a Custom Class on that. You shouldn't need to add a UIView first, just use the one that comes with the View Controller.
Related
If we add scroll view to storyboard it will visible on VC, but it not scrolled Why? Can any one please tell me the answer......
To make it work you need to do following.
Set the delegate property of your UIScrollView.
Set its contentSize.
Make your controller to follow the delegate of UIScrollView by adding <UIScrollViewDelegate>. in your class interface declaration.
I hope you have created your UIScrollView outlet then add this code in your viewDidLoad method.
self.myScrollView.delegate = self;
[self.myScrollView setContentSize:CGSizeMake(WIDTH, HEIGHT)];
I've created a UIView programmatically that embeds several UIControls (UIButtons, UISwitchs and UILabels mainly). I set in the -(id)initWithFrame: of this class the background color.
I have created a message to add the UIControls in the view in order to put inside of my custom view. It's something like that:
-(void) CreateGuiObjects
{
UIView *container = self;
//create uiswitch
mOnOffSwitch = [[UISwitch alloc] initWithFrame:CGRectMake(10, 20, 0, 0)];
mOnOffSwitch.translatesAutoresizingMaskIntoConstraints = NO; //used for constraint testing
//add parent view (self)
[container addSubview: mOnOffSwitch];
/*
other stuff like above
*/
}
then in my view controller there is an event handler for an external button; the action is to add the above custom view in an empty UIView created with Storyboard Interface Builder in Xcode.
the code is like the following:
-(void)CreateButton
{
MyCustomView *view = [MyCustomView alloc] initWithFrame:CGRectMake(20,20,300,200)];
[self.view addSubview: view];
//now call my create method
[view CreateGuiObjects];
}
now, the problem is that it draws the controls, but it seems to position them in a different place...i set the frame origin for the container view in (20,20) and then put the switch in (10,20) where this point is relative to the custom view origin. Instead of that position the view seem to be far away from that position and the second problem is that the background color (gray) set in the initWithFrame is totally ignored.
If i remove every call to addSubview inside the CreateGuiObjects, it draws the empty view with the correct background color and in the correct position.
Edit:
if remove `mOnOffSwitch.translatesAutoresizingMaskIntoConstraints = NO; it works fine...but if i put again it doesn't work. Need to understand deeply the meaning of this property.
Could someone can help me? i think it is a silly question but i'm new to iOS development :(
thanks in advice
Method translatesAutoresizingMaskIntoConstraints = YES means that the UIView is using Auto Layout.
The fundamental building block in Auto Layout is the constraint.
Constraints express rules for the layout of elements in your
interface; for example, you can create a constraint that specifies an
element’s width, or its horizontal distance from another element. You
add and remove constraints, or change the properties of constraints,
to affect the layout of your interface.
When calculating the runtime positions of elements in a user
interface, the Auto Layout system considers all constraints at the
same time, and sets positions in such a way that best satisfies all of
the constraints.
read more about Auto Layout Concepts
If you don't know how to use Auto Layout I would recommend you to turn it off.
I want to show my own custom UIView in storyboard. By far I have done following but my custom view is not showing up.
Dragged and dropped a UIView instance in my screen.
Defined the class for this UIView as my custom class.
Have connected this UIView with an IBOutlet in my view controller.
I even tried with below code in viewWillAppear.
self.myView = [[MyCustomView alloc] initWithFrame:frame];
This works if I create an instance of my custom view and add as a subview to my IBOutlet property for my view. So, below code is working but I want to keep track of only my IBOutlet iVar and do not want to play with another object for changes on my custom view:
self.myExtraView = [[MyCustomView alloc] initWithFrame:frame];
[self.myView addSubview:self.myExtraView];
Any idea how to do this in a better way so that I could have just one reference of my custom view and could change properties on it as per will.
Found the issue. With storyboard we must initialize anything in initWithCode method. I was implementing the regular init method.
I had this question when/where to create and initialize views that are created programatically, so I hope some discussions here will shed more light on this topic for me.
This slide:
says: "not to initialize something based on the geometry of the view in viewDidLoad" and suggests viewDidAppear.
Imagine my view controller has view. I want to add 10 dynamic UIButtons to it.
Shall I put the code like below to the viewDidAppear?
-(void) viewDidAppear:(BOOL)animated
{
...
UIButton *button1 = [[UIButton alloc] initWithFrame: rect1];
[self.view addSubview: button1];
UIButton *button2 = [[UIButton alloc] initWithFrame: rect2];
[self.view addSubview: button2];
...
}
But this creates the buttons each time the view is shown. Is it what we want?
On the other hand if I put the code in viewDidLoad slide suggest not to initialize geometry of these views there.
Or shall we create buttons in viewDidLoad and set their frames in viewDidAppear?
What approach do you usually take?
But this creates the buttons each time the view is shown. It's true.
So the best thing you can do is to add a boolean (lets name it isLaunched). You set it to FALSE in the method -(void)viewDidLoad
Then add a if condition in your -(void)viewDidAppear where you perform creation of buttons (or other stuff) and set the boolean to true at the end.
You should have something like that :
-(void)viewDidLoad
{
//some settings
isLaunched = FALSE;
}
-(void)viewDidAppear:(BOOL)animated
{
if(!isLaunched)
{
//creating and adding buttons
isLaunched = TRUE;
}
}
zbMax (and now Amar) offered good solutions to implement the view creations in viewDidAppear: I will provide the rational for doing this (over viewDidLoad).
It is pretty simple actually. In viewDidLoad none of the views are actually setup yet, so any attempt to set/create frames or bounds will be extremely inconsistent. Struts and springs (or autolayout) will take effect after this method which will create additional changes to your views. viewDidAppear: is the correct place to do this because you can now rely on existing views and setting frames.
Reason for not playing with the geometry in viewDidLoad is because view is still in the memory and not on the window. Once the view is put on the window, then you can specify geometry. That happens when viewDidAppear is called for your controller.
As recommended, you should do all the initialisation in viewDidLoad as this is one time task and need not be repeated. Hold references to the added subviews and give them appropriate frame in viewDidAppear.
When you are dealing with custom UIView and its subviews, layoutSubviews is the method you need to override in the custom view in order to rearrange the geometry of its subviews.
Hope that helps!
There are a bunch of related questions here, but none that feels like a concise or correct answer. Here's the situation:
I am creating a new ViewController and don't want to use a nib file. My understanding from the Apple docs is that if I don't want to use a nib, I should implement loadView to manually create my own view hierarchy.
However, its not clear to me how I should properly instantiate self.view with the proper bounds (given this view controller might be used in a bunch of different situations, setting it simply to the screen bounds doesn't feel right).
Somehow the default UIViewController loadView does seem to properly initiate the frame size, but its not clear if I'm writing my own version what I should be doing to do this.
There is no need to implement loadView. Instead, implement viewDidLoad and create and add any and all desired subviews you want. Just add them to the default self.view.
If you want to add a view that fills the view controller's view then do something like the following:
- (void)viewDidLoad {
[super viewDidLoad];
UIView *someView = [[UIView alloc] initWithFrame:self.view.bounds];
someView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[self.view addSubview:someView];
}
In loadView, you should set the view property of viewController, and nothing else. Adding subviews should be done in viewDidLoad.
- (void)loadView {
self.view = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 80, 40)];
}
Roopesh Chander has an interesting blog post on which strategy to choose: loadView vs viewDidLoad
for Programmatic UI Setup. He recommends setting the frame in loadView rather than viewDidLoad for maximum efficiency.