I have a drawrect method in my main UIView which draws 8 sprites every game tic. I want to seperate out each of these sprites into a seperate UIView.
I am trying to split out one sprite first as a test.
So far I have added a UIView as subview to my main view and set it's frame. This draws a black box on the view. My question is how do I now get get the sprite drawing in the drawrect method to draw into this UIView ?
Thanks all,
Martin
Each view will need it's own drawRect, and somewhere you will need to call setNeedsDisplay on every (sub)view visible. Draw the sprite in the drawRect for the view where you want it to appear. You can either have lots of subclassed uiviews, each with their own drawRect, or a switch case statement inside a drawRect that selects what to draw based on some sort of type-of-subview property.
You might also want to set your sprite's view's background color to transparent, so that they are invisible until you draw into them.
Related
This tutorial shows how to draw on a graphics context for the view using Quartz 2D:
http://www.techotopia.com/index.php/An_iPhone_Graphics_Drawing_Tutorial_using_Quartz_2D
But I want to draw on a UIButton, not on a view. How can I do that?
Thanks
Draw on UIView . Add the view as subview to your UIButton.
A button IS a UIView. It inherits from UIControl, which inherits from UIView.
So buttons have a drawRect method.
So you can do everything described in the article you linked on a button.
However, buttons are set up to do a lot of things for you, and overriding the drawRect method could make those things not work correctly.
Buttons normally draw a title and a rounded rectangle frame. You can turn that off by setting the button's type to custom.
Custom buttons will draw an image if you install one.
Buttons normally also either draw a highlight over their image, or have a second image to use for the highlighted state. If you want to implement drawRect, you'll need to handle drawing the highlighted state yourself.
In general, you want to avoid using drawRect and use some other technique to get the content you want into your views.
What, exactly, are you trying to do?
So I made a UIView subclass let's called it 'MyView' that simply draws a line inside the DrawRect method.
I then drag a UIImageView in interface builder and put it inside MyView. But now when I run the program it's obscuring the line that I'm drawing. I'm wondering, is there a way for me to draw the line on top of the image that I have dragged into my View?
No, you'll have to reorganise the view hierarchy. CoreGraphics uses a painters model so views behind will always be drawn over by views infront. To solve this you could use a container view that holds your image view and has a transparent view (line drawing view) that sits over the image view.
Another option is to draw the image using core graphics calls in your drawRect method and then draw the line over it.
One way is to have whatever adds MyView to add your UIImageView on top of MyView. It's not ideal (you probably have good reasons for keeping MyView and the UIImageView in a single class) but definitely solves your problem (I recently did this, only, I added it to the keyWindow =)
I would use a CAShapeLayer that has a path representing the line, and insert that layer ahead of the built-in view layer. Then it should draw on top.
I have a CATiledLayer within a UIView and the UIView also contains a subview.
How can I make sure that the subview is always drawn above the layer?
Most of the time I get the tile layer covering the subview.
By default all layers (hence views) added in the last are drawn on the top. You can change the default with -insertSublayer:below: and similar methods:
[view.layer insertSublayer:tiledLayer below:thatSubview.layer]
I want to have a UIView subclass that has a border image, but I don't want or care about this 'new' frame/bounds around the border image itself.
What I wanted to do was just use drawRect and draw outside of the rect but all drawing is clipped and I don't see a way to not clip drawing outside of this context rect.
So now I have added a sublayer to the views layer, set [self clipsToBounds] on the view and override setFrame to control my sublayers frame and always keep it at the proper size (spilling over the views frame by 40px).
The problem with this is that setFrame on a uiview by default has no animation but seTFrame on a calayer does.
I cant just disable the animations on the calayers setFrame because if I were to call setFrame on the uiview inside a uiview animation block the calayer would still have its animation disabled.
The obvious solution is to look up the current animationDuration on the uiview animation and set a matching animation on the sublayer, but I don't know if this value is available. And even if it is, I'm afraid that calling an animation from within another animation is wrong.
Unfortunately the best solution is to not use a calayer at all and just add a uiview as a subview and draw into that just like I am drawing into my layer, and hope that with autoresizingMask set to height and width that everything will 'just work'. Just seems like unnecessary overhead for such a simple task.
My solution would be to override the initWithFrame: to add the surrounding border pixels and contain the content in a subview. It probably is unneccesary overhead but definietly the "cocoa" route. It's probably going to be easier in the end too since a subview structure will allow you to edit the content seperatly from the border so you dont have to redraw the border when you redraw the content. And keeping them seperate simply makes sense from a OOP perspective.
The clipsToBounds route is probably the easiest route besides the subview structure but managing the border and content in one drawing cycle and in one object will probably be a lot more work so it'll be worth the overhead.
Excuse any typos, typed this from my iPhone.
My setup is a UIScrollView in the center of the screen (on the iPhone - like 300x400 positioned in the center) that contains a UIView of the same width, so it scrolls it vertically. In this UIView i draw custom subviews with labels etc (it's a scoreboard with various colors).
What i'd like to have is some shadow below my UIScrollView, so that the whole scrolling scoreboard floats over my background.
I have found this nice post
How do I draw a shadow under a UIView?
I use this code in my ScrollView subclass but it doesn't work for me. Maybe because I don't draw the actual shapes in the ScrollView's drawRect: (since they are drawn on the UIView).
Also I guess that in order to have the View scroll in the ScrollView and the shadow of the ScrollView outside the scrolling area, I guess I should extend the "bounds" of the ScrollView, right?
It's not quite clear to me what you're asking but, if you want the scrollView contents to scroll over a static image you simply need to add a UIView (or more likely a UIImageView) to your superview and then add your UIScrollView to that. If you set he background colour of the UIScrollView to be celarColor, the background image will show through - so you have a view heirarchy like:
UIWindow
UIView <----- your background here
UIScrollView
Scrolling subviews <----- high score table here
If you draw your highscore table in the scrolling subviews using CoreGraphics, the answer in the question you linked to will also work.
How about explicitly filling the entire self.bounds rectangle in your scroll view subclass' drawRect: method before calling super?
Another idea is to put the scroll view inside of another view which does the shadow drawing.