I was wondering if anyone could tell me if there is a method in Cocoa that will display information (images) on screen when a button is pressed. What I mean is NSLog "prints text" to the console is there a method that displays images just as easily like would -(void)drawView do it? Is it just setNeedsDisplay? I hope this makes sense. I am essentially wanting to know if I can call something that will display an image as easily as you can display/print text to the screen/console.
The Console is text-only, so no, you can't print an image to it the same way you log text. The closest equivalent is to export the image as TIFF data and write that data to a file in the temporary directory.
As for setNeedsDisplay:, that tells AppKit that the view should be told to redraw the next time the window redraws its views. (In other words, it sets the view as needing display—exactly what it says on the box.) Usually, this is because you've changed the model object(s) that the view displays, either by replacing them with other objects or by mutating one or more of their properties.
You would need to have a view to display; an image view would certainly qualify, but if you're looking for the image equivalent to NSLog, this isn't it, unless you don't mind either making a dedicated window just for showing this image or temporarily putting a image view into one of your real windows.
You should take a look at Apple's NSImageView Class Reference.
This a class you can use to display an image in Cocoa.
setNeedsDisplay is a NSView method that tells the graphics renderer it needs to redraw the image because the data has been modified. Presumably because you are using something like Quartz and you have called some custom drawing code. If you are drawing bitmap images then you probably won't need to use this.
Related
The question may be similar with
Designing inside a scrollview in xcode 4.2 with storyboards
but none of the answer there makes sense at all.
Okay I created a new controller and I added a scrollView.
The very first thing I noticed is there is NOWHERE to specify the content size of the scrollView.
Not in attributes inspector, not in size inspector.
Then what?
I am expecting some larger than normal box where I can draw all the view I want to put in. There is no such thing either.
I am very frustated.
All the "tutorial" out there tell about how to fill scrollView using code.
Another thing I tried is to select controller go to size inspector and then choose FREEFORM.
Great. I still can't make that template big.
Should I do this in XIB instead? At least on that one I can have one huge UIView. Or what is the official way industry standard way of doing this? Is there a WWDC for this one?
Say I want to draw something like these:
I don't think you can get a tutorial on this as it is simply impossible in IB. As most people already commented out what you want to do here need to be done programmatically.
If you are using XIB you can set up all your content there. Under the size tab (in the inspector) you will need to change the height to fill all your content but you still need to set up your contentSize programmatically.
For storyboard I don't think it is possible to change the size of your scrollview in IB.
I have a problem. I want for each record in my core data database to draw an UIImage view on screen. But the problem is that I want to make a sort of grid. On the link below you see what I want to achieve.
picture
So my question is, how do I draw an image on screen in code. And place those images in a sort of a grid. using a collection view is no option, because the app should be running on all IOS devices.
While you could implement a custom UIView and implement the drawRect: method and draw UIImages there, I suggest just using multiple UIImageViews as subviews on your "main" view. Your view might be embedded in a UIScrollView, or you could use a UITableView with custom UITableViewCells. Whichever is easier is probably related to how you can interact with the view.
Building that one huge image view is something that I'd definitely try to avoid - it costs many many (probably unnecessary) memory, and it might be slow as well. Definitely not very flexible to handle, and a pain to update dynamically.
A quick cheat for something like this is to use a Table View and then in each cell to place another TableView but rotated at 90 degrees.
You can then use this second TableView to display the pictures etc...
This will give you a table that scrolls up and down and then each cell can scroll left to right.
I'd suggest subclassing UITableViewCell and setting it up as a UITableViewDelegate and UITableViewDatasource.
You will also have to remember to rotate the content of these "sub"tables by 90 degrees also so that they are the right way up.
This sounds like a lot of work but if you push the management of the sub Tables into the cells then it actually becomes quite easy.
I got trouble to add slideshow to my application.
Currently, I have a UIView composed of a segmentedControl.
I made two "views" that I hide or display depending on the selected button.
I'm looking to make a simple slideshow in one of my two views. I made a UIImageView because it is simple to display pictures.
So I'd like to display my pictures one by one and it is possible to move from one image to another by sliding your finger to the right or left (just as in the native app "Photos").
I tried to adapt example codes from the documentation, but without succes.
So I'ml looking for help.
Thanks,
jb crestot
SO, I've actually done this and it's fairly easy. The ingredient that you are missing is a UISCrollView. My implementation did exactly what you describe (allow the user to go back and forth between a set of images).
Basically, add a UIScrollView to your View in interface builder and you will be creating the UIImage views with code (a simple for loop) and setting their images the same way. I did this safely with no memories issues with about 15 images (PNG's). There could be a potential performance issue with this message if you are working with a large number of images (say 40?)
I hope this helps, let me know if you need a code sample to see how this works.
You may consider using a custom class, such as iCarousel, linked below. Each of these views could be your image, and then tapping on them could launch a fullscreen view for example.
Keep us posted!
http://cocoacontrols.com/platforms/ios/controls/icarousel
See apple's page control sample application.
I have an NSScrollView with an IKImageView inside to display images. This seems to work.
However, if I make the window smaller than the image, the scrollbars appear as they should, but the BOTTOM of the image is locked to the bottom of the window, instead of the top of the image being locked to the top of the window. In other words, I want the image to not move on the screen when I re-size the window from the bottom right.
I understand why this is, because in All of these classes, the origin is in the lower left, not the upper left. However, It's still behaving wrong. If you look at any other product (including Preview, which I assume is written with some of these libraries) the image/content/whatever, is locked to the top not the bottom.
How do I do this?
I've looked for methods in the NSScrollView and IKImageView. I've considered capturing the scroller events and manually moving the image down or up as appropriate, but I haven't seen a way to do this (Set the selector to a method I write in the controller?) and anyway, that seems very messy...
Is there an easy way to do this?
thanks.
Solution for future reference:
Make a subclass of IKImageView with only one over-ridden method:
-isFlipped()
{
return YES;
}
This subclass will also prove useful if I find that I need to re-implement the rotate:(id) method and the setImage:(NSImage) method which exist in the class (and in the case of rotate are USED IN THE DEMO supplied by Apple) but not documented, and therefore not officially supported...
How would print what is in my NSTableView? The View uses core data so everything is stored and can be grabbed as an NSArray. But how would I go about printing it out? At the moment when you click the print button it just seems to take a picture of the view and print that.
Yes, this works exactly as documented. The view is asked for its PDF representation (which, for an unmodified table view, is exactly what you see on screen), then this gets printed.
A view's drawing can be customized for printing versus on-screen drawing, but for a table view, this is more trouble than it's worth.
It might be easiest to generate an HTML representation of the table, then print that. You can use WebKit or just a plain NSAttributedString and off-screen NSTextView. The trick there is to generate the HTML, create an attributed string with the HTML data (there's a method just for that), then hand that to the off-screen text view. The text view would be sized as desired, then you just tell it to print. This gives you control over pagination as WebKit doesn't currently support the print-specific parts of CSS (in other words, it's "screen-only").
What I've done is taken the data and drawn it to a NSView based object in a way that the end-user would want to print. The user then prints that. it's in the docs.
I like Joshua Nozzi's idea, probably much simpler than custom drawing...