I am new to iOS platform and i heard about MVC archtecture.
To draw a circle i just create a separate UIView class and override the drawRect: and able to do this.
But now i want to rebuild the same project using MVC architecture.The main aim is to separate my Model part from View & Controller part.So that i can extend my project.
So how can i do this?
Any sample application for reference?
I'm not sure what you want to separate. Drawing a circle would generally fit into the "View" part of the MVC architecture, which is what you have already done. Code that would, for instance, change the colour of the circle would live in the "Controller" part, which on iOS is a UIViewController. If you had something storing information on what the circle looked like (i.e. size, colour, etc.), that could be considered part of the model, and can be stored in its own class, pulled in by the view controller and passed to the view when it is neede.
Here is a link that may help.
http://www.bit-101.com/blog/?p=1969
As for the model side of things, Core Data is a technology that can help.
http://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/CoreData/cdProgrammingGuide.html#//apple_ref/doc/uid/TP40001075
The separation would be the drawing code in drawRect and the size and location in a model with a controller getting the circle attributes from the model and requesting the drawing and passing the attributes to the view. The model might be another class or an API supplied class such as an NSDictionary.
By creating a separate model if there were multiple circles the controller could make multiple draw requests, one per model circle. Or there could be multiple views that the circle(s) would be drawn in or different representations such as a text list of the circles attributed in one view and graphic circles in another.
Many patterns seem trivial and not particularly useful in the trivial case yet in a real-world program work very well.
Related
I want to Draw lines from one object to another object. Like a Matching object game. I want Swift language with UIKit Use. Here I attach the Sample Screenshot.
Does anyone have experience with this? then please help me.
You have a couple of choices.
You can create a custom subclass of UIView that implements the draw(_:) function to draw custom content. That view would need to big enough to enclose all of your custom drawing. You'd fill most of the view with clear, and then draw the lines you want using Core Graphics.
The other option is to use Core Animation layers. You could add a CAShapeLayer to your view's layer, set up the shape layer with the desired line thickness and color, and add a path to the layer containing the lines you want to draw. (Note that if you use CAShapeLayers, all the lines drawn in a single shape layer will be the same color. You'll need multiple shape layers in order to draw in multiple colors.)
Both approaches will require some research. Shape layers are more efficient and take better advantage of the graphics hardware on iOS devices, but using them has a fairly steep learning curve.
You should be able to google examples of both approaches. Try search phrases like "Custom drawing in a UIView" and "drawing with CAShapeLayer". I wrote a little demo app called OvalView that demonstrates how to create a UIView subclass that manages a shape layer.
Edit:
I adapted the code from my sample app into a demo called LinesBetweenViews. The new demo has a custom UIView that draws lines between any pairs of subviews you put into it.
Here is a screenshot of the demo:
If you answer my questions I can upload the demo app to Github so you can look at it.
Edit #2
See this Github repo for a sample project that draws lines between pairs of subviews.
I'm creating a project in Swift that draws some shapes, based on this tutorial. My project involves some things to most, like removing the shape drawn on the View.
To begin need to recognize them in layers, or uniquely identify what form should remove.
I'm working on it just over two weeks, but I'm running out of idea what to do.
My question:
How can I identify and separate shapes drawn with Core Graphics in Swift?
I found the way:
for layer in self.view.layer.sublayers! {
print(layer)
}
I can get all layers drawing in my view.
All you ios architects out there, please help me choose architecture/technology for the following iphone/ipad app.
The app itself is a financial app, but we want more of a game look-and-feel of the app, so we probably don't want to use the builtin looks of the cocoa widgets. The elements on the screen will probably be some kind of blob-shaped images.
The app will essentially have five "blob"-shaped areas, spread out evenly across the screen. One of the blobs will be centered and larger than the other ones. Within each blob there will be clickable areas which will pop up "details" and menu-action blobs. These blobs are also graphics objects and must not take over the whole screen. The blobs should animate nicely when popping up. The graphics elements will have a couple of lines of text, which are generated, so the overlaying text itself cannot be part of the static background-image.
The main user interaction will be swiping within the center blob, displaying summaries of the items that are conceptually contained within the blobs underlying data store. Now and then, the user will drag and drop the item to one of the other blobs. While dragging, the item should be traced by a line and when dropping on the other blob, the item should be animated to look like it's being "sucked into" the blob.
Now, what kind of technique would you suggest for this app? Is Cocoa suitable in this scenario? Should I use a game framework like Cocos2D? All kinds of suggestions including example code snippets are most welcome.
I realize that this question might not be as straightforward and to the point as questions generally are on SO, but I hope your answers will come to use by more people than me. Thanks!
EDIT (MY SOLUTION):
I eventually ended up doing everything in UIKit, which was a lot easier than I expected.
Briefly described I used UIButtons with Custom style and an image background, which gave me full control over the visual appearance of the "items". I also found it very useful to manipulate the underlying CALayer of many of my other UIViews. It is often easier than drawing things from scratch using Core Graphics programming.
Another thing that was useful were the UIGestureRecognizer:s. I found them useful for both handling "real" gestures like swiping, longpress etc, but also for handling normal "tap" for UIView classes that aren't subclasses of UIControl. Two examples are UIImage, UILabel and UIView itself. That way I could handle taps for these simple classes. I could for example use a normal UIView, modify it's CALayer to change the look of it completely and still handle taps. Using this technique, I didn't have to subclass any views at all in my app.
The animations were pretty easy too, even though I had to use a non-public method to use "suck" animation, so my app will never pass App Store moderation. It was just a prototype anyway so I don't care.
When this app will be for real, I will probably implement it in HTML5/JavaScript wrapped by Phonegap. The reason for this is mainly reuse of existing mobile web services and also for code reuse across platforms. It will probably also be easier to hook into the existing security solution when using a webapp.
Cocos2d is great if you need to move elements around really fast as it is a layer on top of OpenGLES. I think from what you have said the UIKit will be fine, you get nice animation support, you can do some nice things with UIScrollViews to handle moving elements around etc.
If you need more detailed graphics support and lots of moving elements, particle effects etc then by all means go for Cocos2D but be aware that in Cocos2d the application works more on a scheduled update method, i.e. you get notified every 1/60th of a second to move stuff draw stuff etc, whereas with normal UIKit approach it is more event drive, i.e. I click a button and show a view etc.
I'm pretty new to iphone development, so this is more of a high-level question. The simplest description of what I am looking to do is create a zoomable/panable field on which I can place a bunch of circle objects. The number of these circles is likely to be in the hundreds, and ideally when the user zooms in close enough, more information can be displayed. From stuff I've read, it seems like UIScrollView provides the simplest way of making a zoomable/panable view but I'm not sure it's the best way to handle a view that includes a hundred graphic objects. I'm trying to figure out if I should progress further down that path or look into things like CALayers, Core Graphics, etc. Any guidance or advice would be greatly appreciated. Thanks in advance,
Roman
I suggest you to use UIScrollView, because it will save a lot of time for handling proper zooming/scrolling. So the workflow is next:
1. Zoom you scroll view
2. In delegate's callback scrollViewDidEndZooming:withView:atScale: you can obtain the scale and determine the level of detail that you need.
3. redraw the visible region (using Core Graphics) with appropriate level of detail (number of circles etc.)
So you should use the mix of Core Graphics and UIKit.
I'm trying to make a little iPad tool's for drawing simple geometrical objects (rect, rounded rect, ellipse, star, ...).
My goal is to make something very close to Keynote (drawing feature), i.e. let the user add a rect (for instance), resizing it and moving it. I want too the user can select many objects and move them together.
I've thought about at least 3 differents ways to do that :
Extends UIView for each object type, a class for Rect, another for Ellipse, ... With custom drawing method. Then add this view as subview of the global view.
Extends CALayer for each object type, a class for Rect, another for Ellipse, ... With custom drawing method. Then add this layer as sublayer of the global view layer's.
Extends NSObject for each object type, a class for Rect, another for Ellipse, ... With just a drawing method which will get as argument a CGContext and a Rect and draw directly the form in it. Those methods will be called by the drawing method of the global view.
I'm aware that the two first ways come with functions to detect touch on each object, to add easily shadows,... but I'm afraid that they are a little too heavy ? That's why I thought about the last way, which it seems to be straight forward.
Which way will be the more efficient ??? Or maybe I didn't thought another way ?
Any help will be appreciated ;-)
Thanks.
I'd use the UIKit classes to do your drawing, then profile and optimise your code from there.
Apple/iPad info: link text
My first feeling was to make the 3rd way, but to be convinced, just after I've posted my message, I did some tests with just a global view and over 200 geometrical forms (Rect, Rounded Rect and Ellipse) on it and I move only a half with touchMoved event. I did this test with the way 1 (Subclassing UIView) and the way 3 (Subclassing NSObject), the way 2 seems to me too restrictive and not help me at all.
The resuslt is that the way 1 seems to be more efficient... There is no lag when I move 60 objects together ! Moreover using this way would probably help me because using view comes which some interesting functions like touch detection on complex path (see UIBezierPath), object hierarchy handled by the UIView classe...
So I will use that way and come back here to share my results ;-)
Regards
It's better to use CGLayer objects. The benefits are:
It's much faster and more memory efficient. For simple objects, adding a view is much more expensive and complicates the view hierarchy. For complicated objects, the caching done on CGLayers can boost performance.
It's easy to group objects together. you just put everything in a new layer, and voila! There's almost no overhead.
Using CGLayer and other Quartz objects gives you a lot more flexibility.
The only drawback is that you have to directly use Quartz 2D. It's not really difficult, but needs some learning if you haven't used it before.
CAShapeLayer pretty much handles your option 2. It does rect and rounded rect (see cornerRadius) by default, or you can give it a path for any arbitrary shape. For your option 1, you can use a CAShapeLayer with a UIView instead of implementing drawRect and it may be faster.