I'm making an OpenGL ES application and I am trying to work out how to incorporate parts of the UIKit GUI over the view with the OpenGL ES working on it.
In the init method of the EAGLView class I have this to setup the UITextField:
add_name_field = [[UITextField alloc] initWithFrame: CGRectMake(10, 10, [UIScreen mainScreen].bounds.size.width, 50)];
Somewhere in the drawRect method where everything is rendered and processed for the game I have:
[add_name_field becomeFirstResponder];
[self insertSubview: add_name_field atIndex:0];
I can confirm this code is called because I used NSLog to test that but when it is run the text field does not show over the game's OpenGL view. If I put the code in the init method, the text field shows properly with the keyboard at te beginning of the game.
So how do I get it to work in the drawRect method?
Thank you for any answer. I will write some code for the delegate in the meantime.
THank you for all the other answers but I found the solution.
It was a simple solution. I simply moved the addSubView method to the initialisation of the EAGLView class. The keyboard wont show until I make the text field the first responder. When I'm finished with it, I can simply clear the text and make the EAGLView class the first responder again and that hides it all again.
This way I can simply use the keyboard to get text input for my game, displaying text when typing and hiding it afterwards.
I assume you're in a UIViewController subclass, with the code above? If so, then instead of
[self insertSubview: add_name_field atIndex:0];
do:
[self.view addSubview:add_name_field];
The important part is, you're calling this method on self.view rather than self. Adding subviews is a VIEW function, not a View CONTROLLER function.
insertSubview:atIndex: ought to work too (if called on the right object), but addSubview: will stick it on top of the view no matter what else is there, so it's a bit cleaner.
Add your text subview outside of drawRect. drawRect is for rendering that one view, and may or may not ignore drawing any other views (such as your text view), depending on how the view stack is rendered.
Is there any reason to have it done in the drawRect method? You said that it works fine in the init method, so why not have it there?
As for why it doesn't work, I don't exactly know OpenGL views but, assuming they work just like regular UIViews, you probably shouldn't be adding other UIViews in the drawRect function. UIViews don't get shown & drawn immediately; they have to wait till the runloop tells them to draw. Likely what happens is that when your superview's drawRect finishes, it assumes all its subviews have finished drawing and doesn't realized that your newly added textfield didn't get a chance to. What you could try is calling setNeedsDisplay on your textfield.
Related
In a new Single View App, the following code:
- (void)viewDidAppear:(BOOL)animated {
self.fooView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
self.fooView.backgroundColor = [UIColor yellowColor];
[self.view addSubview:self.fooView];
[UIView animateWithDuration:2 animations:^{
self.fooView.backgroundColor = [UIColor blueColor];
}];
}
will animate the yellow background to blue. The fooView is just:
#property (strong, nonatomic) UIView *fooView;
But if a custom view class FooView is defined, and I change the above code above by replacing UIView with FooView, and also define an empty -drawRect for FooView, then there will be no animation -- the background is just changed to blue immediately.
It made no difference if using [UIView animateWithDuration: ...] or [FooView animateWithDuration: ...] -- it is no animation.
If inside -drawRect, I call [super drawRect:rect];, then it is the same thing: no animation.
If I change drawRect to drawRect2, or if I remove the whole method, then the animation will work.
(and the -drawRect might be needed, for example, what if we need to draw a circle in the custom view FooView?)
Why is that? Besides giving a solution of how to make it work even with a -drawRect, please explain what was going on that made it not animate?
The presence of drawRect: changes the way UIView operates. You should only use drawRect: when absolutely necessary and you should never have an empty drawRect: implementation.
If the -drawRect: method is present in your subclass then UIView must do a number of things before it can call this method. Namely, it must allocate a potentially expensive backing store into which your custom drawing will occur, and it must fill this backing store with the background color.
UIView will then call your drawRect: implementation to do any custom drawing on to the backing store, before handing the backing store to the GPU. Only after all that does your animation block begin to run.
So at the start of your animation the backing store that represents your custom UIView has already been painted a new background color.
If your UIView subclass has no drawRect: method then the view has no backing store. The background color is handled directly by the GPU, which can very efficiently animate transitions between colors.
Empty UIView objects (without a drawRect: implementation) are rather lightweight. Your custom view should be composed of multiple subviews depending on what animation effects you want to achieve.
For example, the UITableViewCell class is composed of many subviews. UITableViewCell itself is a UIView. It contains a background view and a selected background view. On top of that is the content view, and inside the content view are various text labels and image views. All of these views combine to produce the selection and resize animations you see in a regular UITableView.
Using 'CATransition' class .You will have to be do animation.
Using this method
+(CAAnimation *)setAnimation{}
Use following line in animation Block
[self.view addSubview:self.fooView];
Instead of this we have to create a new class and using the CATransition and using this class methods '+(CAAnimation *)setAnimation'.We have to create an object for this and call when will transition happen
In my app I have a scrollView with about 20 subviews in it. Each of these subviews has a drawRect method that at the moment looks like this:
- (void)drawRect:(CGRect)rect
{
NSLog(#"drawRect called");
}
When the subviews are added, drawRect is called, however when I scroll it is very slow even though drawRect is not called again.
If I remove the implementation for drawRect, then scrolling is completely normal. Even if I can't get rid of the slow scrolling, is there an alternative to drawRect which I could use instead?
Why are you calling drawRect if it is only logging that it was called? If that is it's only purpose for you, then just don't call it. In fact, I believe when you first create a class that inherits from UIView that has the drawRect method in it, it is commented out and above the commented out drawRect method, it says something along the lines of "Do not call this method if it does not do any drawing on screen as it takes up a significant amount of memory". Basically, don't call it in your case.
Hope this helps.
You could try assigning pre-drawn CGImages to the contents of each custom view's CALayer, before the view first appears. This may be faster than using a drawRect to customize a view's appearance.
I have subclassed UIView so I can draw some lines in it. In this UIView are a whole bunch of buttons which I decided to create as a method that drawRect calls after the lines are drawn. It works but sometimes only part of the button renders. If i remove the button creation and instead add the UIButton in the subclassed UIViews parent it works fine.
Is doing things like adding subviews in drawRect method a big no no or should I not do it all together in UIView?
yea that's a pretty big no no. drawRect is for adding stuff with CG, not views. It gets called repeatedly and unpredictably. Adding them in initWithFrame should be pretty safe though.
In my iPhone app, I have a view controller with two views (essentially, a front & back view). The front view is the main UIView, and the back view is a secondary UIView which is added as a subview using [self.view addSubview:backView] when showing the back and [backView removeFromSuperview] when hiding it. However, when the orientation changes, I have the following issue: the main UIView (frontView) rotates & all of its elements resize properly, but the secondary/subview UIView (backView) does not rotate & all of its elements do not resize properly. Does anyone have suggestions on how to make the secondary UIView autoresize properly according to the rules I have set in Interface Builder?
In the end, the solution I found was simply to separate my UIViews into separate UIViewControllers, and make sure that any views that I wanted to be able to rotate only had one UIView.
If I understand correctly, at the time of rotation 'backView' has been removed from it's superview, yeah? If so, that's the cause of the problem. The autoresize property determines how the view resizes relative to it's superview. If it doesn't have a superview it won't resize.
Perhaps using [backView setHidden:YES] instead of [backView removeFromSuperview] will be sufficient for your needs.
I had the same problem, here is how I fixed it based on imaginaryboy's
suggestions (thanks!)
Add the backview to the viewcontroller at viewDidLoad and hide it at the same time. Show it when needed, Hide it again. Set the resizing of the backview to UIViewAutoresizingFlexibleWidth in IB (or code I guess, I used IB)
Not that this is the same problem, but I found a similar problem when adding 2 subviews in my application:didFinishLaunchingWithOptions method. Since your reference above is using [self.view addSubview:view], I would understand that to mean that self is not your UIWindow. When adding an additional view controller to your App Delegate window (UIWindow), the second view controller will NOT receive any rotation events and will never rotate. Only the first view controller added to UIWindow will rotate. See:Technical Q&A QA1688 I believe this also affects views added after the first view where the first view is later removed from the superview.
I ended up following the suggestion I read elsewhere to use separate views for each orientation, thereby eliminating the need to worry about resizing behavior. As always, YMMV.
Or; if you want to avoid an additional controller, you can achieve the same effect by setting view.frame in willRotateToInterfaceOrientation:: like so
if(UIInterfaceOrientationIsLandscape([[UIApplication sharedApplication] statusBarOrientation])) ;//set stubborn view.frame for landscape orientation
else ; //set stubborn view.frame for portrait orientation
Although it feels like a hack; it's simple.
I have a UIScrollView contained within a custom UIView with a content size larger than the ScrollView's frame.
I am able to drag scroll as I expect, but the thing doesn't give me the rubber banding effect that you get with the UITableView or UIWebView. It just stops when you get to one of the extremes.
I have set bounce = YES, is there something else I'm supposed to do?
I read the docs, and they say I have to implement the delegate. I did that.
They also say I should change the zoom levels, but I don't want the user to actually be able to zoom so I haven't set these.
For anyone that finds this thread later, if you are subclassing UIView and re-setting the UIScrollView's frame on every layoutSubviews, that is the problem - it cancels the bounce:
http://openradar.appspot.com/8045239
You should do something similar to this:
- (void)layoutSubviews;
{
[super layoutSubviews];
CGRect frame = [self calculateScrollViewFrame];
if (!CGRectEqualToRect(frame, self.scrollView.frame))
self.scrollView.frame = frame;
}
I had the same problem, on a UIScrollView that wasn't all filled up (but I still wanted it to bounce). Just setted:
scroll.alwaysBounceVertical/Horizontal = YES;
And it worked as expected
It turns out that keeping the UIScrollView within my custom UIView was causing the trouble.
Once I switched my custom UIView to instead inherit from UIScrollView, then the bouncing started working.
That is interesting... Is there a lot going on while the user scrolls the scroll view? Maybe that could cause the problem. The iPhone can multitask, but not too much. Can I see your entire code having to do with the scroll view?