i want to animate a change to the image used when displaying my mkannotationview.
i know that uiimageview allows for animating its image, but the mkannotationview is just a uiview with an image property.
i also realize that i could override the drawrect method of mkannnotationview, and fully customize the way the pin is displayed/updated, but i'd like to avoid that if possible, and simply animate the change of the image property.
is this possible, or is the drawrect approach my only option?
thanks
a timer could be used to change the image property on a set interval, or - you could subclass the annotation view and add your own uiimageview to the view hierarchy, and expose the uiimageview as a property.
Related
I have a view in a window, the position and size of the view are calculated with autolayout. The view has a subview, a draggable NSView subclass. It is really easy to make a NSView "draggable" by overriding -mouseDown: and -mouseDragged: and changing the frame of the view directly.
The view hierarchy is as follows,
What is the best way of making the subview draggable in this case?
For example,
Is it possible for the subview to not use autolayout, so that it can be positioned by changing the frame directly? i.e. the window positions the main view, but then autolayout does not layout the subview inside the main view. Or do all views in the hierarchy need to use autolayout?
When I have used autolayout before, I have used it to make "fixed" layout that respond to resizing. But dragging a view with a mouse does't seems like a natural use-case for autolayout.
Is it possible for the subview to not use autolayout, so that it can be positioned by changing the frame directly?
Yes. If you keep translatesAutoresizingMaskIntoConstraints turned on, it automatically creates constraints from the values of frame and autoresizingMask.
In fact, this means it will use Auto Layout, but you can work with frame just like with manual positioning.
The best way is to not avoid auto layout.
Making a view draggable is pretty easy with auto layout constraint IBOutlets and getting the mouse delta from NSEvent short circuit mouse tracking.
I've been looking for solutions but can't figure out if it is possible to do the following:
I have a drawRect method, what i want to do is to add a graphic element (such as rects and lines) to the current view without refreshing it. I used to call setNeedsDisplay but this method is actually deleting myView an re-drawing it from 0.. Any suggestion to keep the old one and add new content ?
Thank
Every time an update is made in a view the entirety of it is redrawn; so -drawRect needs to redraw the entire view. You have to 'refresh' your view - it's the norm - there's nothing wrong with it. Just draw the old content again.
Or, you could call setNeedsDisplayInRect: if you do want to just redraw a specific section of your view.
That's what drawRect: does - it redraws the rect in the view.
If you want lines and rects drawn on top, try doing it on a different layer.
I guess it's better if you work with layers.
You can make CALayer subclasses for your shapes, and then save them in an array.
By default , the drawRect method will clear the whole content , if your want to dynamic draw some new graphics contents to the view ,you should abstract these graphics element's data structure , for example , you add a line ,this line will have
a start point
a end point
line color
line width
is has a shadow
a line join
so you can put all these property into a struct and define a new Data Class named LineStruct and define a method called
-(void)drawLine:(CGContextRef)ctx withLineStruct:(LineStruct*)lineStruct
to your custom UIView , define a
#property (nonatomic) LineStruct *lineStruct ;
and invoke in it's drawRect method
-(void)drawRect:(CGContextRef)ctx{
CGContextRef ctx = UIGraphicsGetCurrentContext() ;
[self drawLine:ctx withLineStruct:self.lineStruct];
}
so if your have other graphic contents , you can do the draw like that . If you have lots of
contents , you must add a buffer to your UIView ,such as add a NSArray , and in the drawRect method ,you add a for(;;)to draw all the graphics elements
I think maybe you need something like an NSBezierPath to store all your shapes and add new shapes. It's easy to add new shapes to an existing NSBezierPath, see the documentation: https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSBezierPath_Class/Reference/Reference.html
Then in your drawrect, you will only have to stroke or fill the NSBezierPath.
This will only work if all your shapes have the same fill color and stroke. Otherwise you could keep some kind of list of multiple NSBezierPaths and stroke/fill them in different ways.
You can 'get around' this by making the view you want to draw in separate from your view with the original iboutlets. Then make your main view background transparent (but do not make the iboutlets transparent). So for this example, I will prevent that the IBOutlets you want to keep (not draw over) are a UITextField, a UILabel and a UIButton.
So you Interface Builder will look like this:
UIVIewController
UIView2 (view with drawRect defined)
UIView (main)
UITextField
UILabel
UIButton
So as you see, when you call 'drawRect' it will still blank out your UIView2 completely, but it won't matter because 'drawRect' won't delete any of the UILabel, UIButton, UITextField or whatever else you want to keep in your UIView1. Hope this helps.
For an iPad app I am writing I have a container UIView with two subview that are UIView subclasses:
A UIImageView whose image has a portion of it cut away to reveal what is below it.
A UIButton below the UIImageView that is revealed through the cut away portion of the UIImageView.
Since the UIImageView overlaps the UIButton spatially it is preventing touches from reaching the UIButton even though the UIButon is fully visible due to the alpha matte cutout in the UIImageView. How do I allow the UIImageView to pass touches to it's sibling UIButton?
Thanks,
Doug
UIImageView usually won't block touches, UIViews do.
You can set the userInteractionEnabled property on the overlapping views to NO, then touches should go through them.
An other approach would be writing a custom hitTest that redirects the thouches to the button.
In addition to Bastian's answer it was also necessary for me to uncheck the Opaque drawing attribute in interface builder for my UIImageView
Even with user interaction enabled, which is the default value when placing a UIImageView in Interface Builder, the touches should pass through to your button underneath, even if your image view has a solid background. Something else must be going on like a UIView sitting on top of the button.
If you are trying to do something more complex to get touches to pass through to underlying views or a separate view controller whose view is underneath, I created this simple open source library:
https://github.com/natrosoft/NATouchThroughView
The REAMDE and demo show how to use it.
I have a custom view which needs to be relaid on orientation change. My UIView code can correctly redraw for the any orientation as it express itself in screen frame size.
But how do I get the loadView method to run on orientation change for the right view to get drawn ?
I put [self.view setNeedsDisplay] in the following rotation handling methods with no luck.
willRotateToInterfaceOrientation:duration
didRotateFromInterfaceOrientation:
Any suggestions would be most welcome.
loadView actually causes the view to be completely re-created from scratch. It should be sufficient to call setNeedsDisplay in didRotateFromInterfaceOrientation on the view that needs to redraw.
If you have to change the layout of your views upon rotation, do so in willAnimateRotationToInterfaceOrientation (so the changes get animated), and/or set the autoresizingMask property to the combination of UIViewAutoresizingMask values that suits your needs.
I created UIImageView with the help of Interface Bulder. Now I want to place label inside it (as its subview). In code I can type something like: [myUIImageView addSubview:myUILabel]; But can I do it with the help of IB? I found the solution for UIView, but can't find something similar for UIImageView.
You cannot add a subview to UIImageView in interface builder for reasons only known to Apple! You are right in saying that you can addSubview programmatically, but then, the overhead of setting autoresizing masks and placements of subviews should all be handled in code, which is cumbersome.
So there is an easy workaround. Instead of dragging an instance of UIImageView in the nib, just drag a UIView and change its class to UIImageView from UIView (cmd+4 option of inspector). The only difference you find in the nib for default imageView instance and your new UIImageView subclass instance is: you cannot set image to your new imageView from nib (cmd+1 option). So, in the -viewDidLoad method of its appropriate viewController, set image to this outlet of UIImageView.
By doing so, you are free to add subviews to your "now UIImageView" instances in interface builder, which is much easy.
I would like to add answer.
While it sucks you cannot add subview to UIImageView, you can get the same effect by incorporating UIView with transparent (clear color) background.
Then put the UIImageview BEFORE it.
So the UIView has the subviews and the UIImageview is the background of the UIView.
I think that's apple's intent.
Here is a screenshot:
Here is the result:
Don't forget to set background as clear color
Now if someone could actually point me to a tutorial how to do this it'll be great. I spent hours doing it the checked answered way. The checked answer is a fine answer but very unintuitive because you can't see your background image clearly while working. I think mine is the proper way to do so.
In latest XCode(4.5) there is an option to drag and drop the required controls to the parent.
It is quite easy.
Attached screen shot for the same. I dragged the Label/TextField and Button to UIImageView
Use this code:
UIImage *image = [UIImage imageNamed:#"background.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
[self.view insertSubview:imageView atIndex:0];
(replace background.png with image) (replace atIndex:0 with whatever place in the .index root you want to insert the image and your off.