I'm looking at an iPhone application, with several ViewControllers controlled by a UINavigationController.
Somewhere deep down one of the ViewControllers is creating a view, and the view is trying to pop a
UISegmentedControl *segmentedControl
up on top of itself like so:
[self.window addSubview:segmentedControl];
"self" is a specialized form of UIView, and the control's frame is set
segmentedControl.frame = someFrame;
For some reason, the control is not showing up on top of the current view. Should this work, and, if it should, what are the most likely causes of trouble?
When you say self is a specialized form of UIView I'm guessing you are referring to a UIView custom subclass.
If you are adding the UISegmentedControl from within this view, you want to do the following:
[self addSubview:segmentedControl];
You set it's frame relative to it's superview, so if you want it on the top left corner you would do:
segmentedControl.frame = CGRectMake(0.0f, 0.0f, someWidth, someHeight);
Related
I'm kinda new to iOS development.
I want to have a custom View and some Labels inside it. And In some viewControllers of my app on a button click I want to add/show that View
at the bottom of that viewController.
As far as I'm manually adding the view in storyboard in all the viewControllers in which I want the view to display. But this is not efficient. How can I add this view in viewControllers programmatically on button click?
Make one BaseViewController class inherited with UIViewController
Now create method named as designFooter in BaseViewController
func designFooter() {
var viewFooter: UIView = UIView(frame: CGRectMake(0, self.view.bounds.size.height - 50, self.view.bounds.size.width, 50))
viewFooter.backgroundColor = UIColor.redColor()
self.view!.addSubview(viewFooter)
}
For Swift 4, 5.1:
func designFooter() {
let viewFooter: UIView = UIView(frame: CGRect(x:0, y:self.view.bounds.size.height - 50, width:self.view.bounds.size.width, height:50))
viewFooter.backgroundColor = UIColor.red
self.view.addSubview(viewFooter)
}
Now inherit this BaseViewController to you ViewController where you want to add footer, and on button click just call self.designFooter()
If this subview you want to add has some dynamic content or has much of its own logic, you might want to employ view controller containment, specifically not only add a subview, but add a controller associated with that subview, too. So, you can have a scene in your storyboard for this subview that will appear on the bottom, and associate it with its own view controller. Then, when you want to add it, you'd do something like:
let child = storyboard!.instantiateViewController(withIdentifier: "storyboardid")
addChild(child)
// set the `frame` or `constraints` such that it is in the correct place, perhaps animating it into place
view.addSubview(child.view)
child.didMove(toParent: self)
And when you want to remove it:
child.willMove(toParent: nil)
child.view.removeFromSuperview()
removeChild(child)
Personally, if this can really appear and disappear from any scene in my app I actually embed the whole app in a container view controller. Then this popping of the child in and out only has to be done once, on this master container view controller.
For example, consider this storyboard:
That is an embedded "container view" (the storyboard equivalent of view controller containment, discussed above). And I can then have a label animate in an out (by animating layoutIfNeeded after changing the height constraint of some view with a label). Then, this bottom view can animate in and out regardless of which view controller's view is currently visible:
Just create a UIView and call addSubview:
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0,0,100,100)];//change this frame for your purposes
UILabel *l = [[UILabel alloc] initWithFrame:CGRectMake(10,10,50,10)];
[l setText: #"My label"];
[view addSubview: l];
[self.view addSubview: view];
As far as adding this to multiple view controllers... I suppose if you had a lot of different view controllers with this same UIView you could create a subclass of UIViewController called CustomViewController. In that class add the above code to viewDidLoad. Then, subclass CustomViewController in all the view controllers with this particular view, and they will automatically add it for you.
Edit:
If you want to design the view in interface builder, make a custom subclass of UIView. Let's call this CustomView. Design it in a nib and add any code you want. Then, whenever you want to create that view, simply call CustomView *cv = [[CustomView alloc] initWithFrame:...] and then do [self.view addSubview:cv];
I have a view with some UI components and a button on it, upon touch of a button I want to show a half view with some textfields on it overlapping the initial view, the initial view should be visible partly , the overlapping view will cover only half screen from bottom. Is this possible ?
I don't have any code as I am unable to figure out what it needs to be done, as we show any view it covers the entire screen.
Thanks
there are several ways you can do this, here are two:
1) add a popover controller that gets displayed on your button press:
here's some apple documentation on popovers: https://developer.apple.com/Library/ios/documentation/WindowsViews/Conceptual/ViewControllerCatalog/Chapters/Popovers.html
2) add the new view as a subview to your UIViewController
PROGRAMICALLY:
in the viewDidLoad function you can do the following to initialize the halfScreenView
GLfloat topOffset = self.view.frame.size.height/2;
UIView halfScreenView = [[UIView alloc] initWithFrame: CGRectMake(0, topOffset , [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height - topOffset)
[self.view addSubview:halfScreenView];
-more logic might be needed if you support Landscape orientation, you can always re-assign the location of the view with halfScreenView.frame.origin and halfScreenView.frame.size
-initially you can have this view be hidden
halfScreenView.hidden = YES;
-when you click the button it will show the overlaying view:
halfScreenView.hidden = NO;
USING STORYBOARD:
you can also set up your overlaying view in the storyboard if you have one
-drag a UIView into your UIViewController and set it up where you want it to be located
-initialize the view to be hidden by checking the hidden box in the attribute inspector
-add the view as a property to your view
-manage when to show this view with self.halfScreenView.hidden
-this technique allows you to customize what is inside the new view within the storyboard which is nice
FOR BOTH:
-be careful with layers, you don't want your view to show up behind the one you already present. In the storyboard the last thing inserted goes on top. With in the code you can always access/change the views z position with halfScreenView.layer.zPosition (higher z values are on top)
First create a new class subclassing UIViewController called SecondView (or whatever you want), then design the UI the way you want (in its .xib file)
Then go to your main view controller's file and make an IBAction for that button.
In that method, write:
SecondView* second = [[SecondView alloc] initWithFrame:CGRectMake(0, [[UIScreen mainScreen] bounds].size.height/2, height, width);
[self.view addSubview:second.view];
This will add it to the bottom half of the screen. Put your own parameters for its height and width. When you want to dismiss the view, you can do this inside your SecondView class
[self.view removeFromSuperview];
You can deal with the textFields from within the SecondView class and have them communicate with your other view by doing the following in SecondView.h
#property IBOutlet UITextField* textField;
Hope this helps!
Yes, assuming you are using Interface Builder, go ahead and build the overlapping view and hook up all of the IBOutlets and IBActions. Say this view is called myView. Set myView.hidden = YES and myView.enabled = NO. This hides and disables myView so that it isn't even there from the user's perspective. In the appropriate button's IBAction, change the hidden and enabled properties to YES. That will make the view visible and active again.
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 have a custom UIViewController which create a view containing an action bar at the top (view with 4 buttons), a tableview and then another view below the tableview. Layout is done all in code and is not using auto layout.
Everything works perfectly on various device with iOS 7.0 and 7.0.2, but in the simulator, the root view of the controller get anchored at the top right corner of the screen (0,0) instead of below the navigation bar.
I'm going to force the relay out in the viewDidAppear: method, but this seem like a hack...
Thanks for any insights
Edit: added an image. You can see the UIView highlighted. As ManicMonkOnMac mentioned, the UIView is under the toolbar (but this only happens in the simulator, on the device, the view lines up fine)
In the loadView method on the controller, i set the frame when creating the view:
- (void)loadView
{
// Our parent view controller will resize us appropriately. The size set
// here is a convenience for initial view layout.
self.view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 320)];
self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
}
But this frame is later changed. Not by my code, though, but by UIkit code)
Edit2: addded loadView method body
EDIT: After going through session 201 of WWDC 2013, I think I have the solution.
in iOS 7 there is a property that you can set on your view controllers to specify whether you want the views to be overlapped by navigation bar.
viewController.edgesForExtendedLayout = UIRectEdgeNone;//UIRectEdgeAll specifies that nav bars should overlap the view.
Unlike iOS 6, navigation bars are placed over the views in iOS 7.
Use the frame size that excludes the navigation bar.
code:
CGRect frame = CGRectMake(self.view.frame.origin.x,self.view.frame.origin.y+self.navigationController.navigationBar.frame.size.height,self.view.frame.size.width,self.view.frame.size.height);
CustomView *view = [[CustomView alloc] initWithFrame:frame];
[self.view addSubview: view];
I'm trying to make a square (50 x 50) UIView in the lower right hand of my main view, but I'm confused about why it's not entirely visible. In this instance, only the tip of it is visible from the bottom. Am I confusing some concept?
CGFloat width = CGRectGetWidth(self.view.bounds);
CGFloat height = CGRectGetHeight(self.view.bounds);
UIView *transparentFloater = [[UIView alloc] initWithFrame:CGRectMake(width - 50.f, height - 50.0f, 50.0f, 50.0f)];
[self.view addSubview:transparentFloater];
Try to add the autoresizing mask:
transparentFloater.autoresizingMask = UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleLeftMargin;
If I am not wrong, You have created your ViewController with xib and in the attributes of view, you have forgot to mention that you are using a "navigation bar" as "top bar".
Reason
So in ViewDidLoad, view in .xib with a height X is returned. But as you might have loaded the viewController using UINavigationController, after loading the height of view is decreased by 44pixels.
Suggestions :
1) Whenever you know that you are going to have navigation bar on top please mention it in .xib file as well.
For doing so click on the view in xib and select the option called topbar in attributes Inspector of utilities area
2) Call the following api
NSLog(#"In ViewDidAppear %#",NSStringFromCGRect(self.view.bounds));
in
viewDidLoad
viewDidAppear
to track whats happening with the bounds of view
You does not need to do anything just put
transparentFloater.backgroundColor = [UIColor redColor];
because your view (custom) is invisible (because your main view color and custom view color are same (white) ) may be. I tried your code in my demo project. it worked perfectly for me.