Cover screen with window in cocoa - objective-c

I am writing a Mac application, in Cocoa, that needs the ability to 'lock down' the computer. Basically, I am writing a small agent that will sit in the background and when prompted, throw up a window that covers the entire screen, including the status bar, and shows a message (something like "give me back my computer, thief!").
The window has two requirements: it can't be moved and it can't be closed, minimized or otherwise disabled - just a big blob sitting on the screen, making sure the thief can't use the computer. I have all the agent stuff lined up, but I need help coding this window. Does anyone have any ideas?
Thanks,
Chris
P.S - In my dream world, this window would show up even at the login screen. The agent will be running by then, but I am not sure if OS X will allow it...

What you're asking for is basically to turn the user's computer into a not-very-functional kiosk. See also this technote on the same subject.
For display, alternatives to the full-screen view mode described in the Kiosk Mode document include:
Capture all the displays and draw directly to them using Quartz Display Services.
Set your window's frame to the frame of its screen and set its window level really high. You'll need to create one such window per screen.

Related

Possible to make an OS X with a window that blocks a portion screen like the system menu bar?

Is it possible to create a NSWindow that will not only is above all other windows (including other applications) but also able to block windows from going "into" that window. Basically I would like to extend the system's menu bar by having another bar below it, but it stops the user from resizing other windows to occupy that space.
For instance, if the user was to maximize a window, it would only be able to have a height of the screen size minus the system status bar minus my application's window.
I was thinking it may be possible by listening to some sort of window resizing notification and if the user tries to set the frame of that other window to a size that would go inside of my application's window then I would resize the other window, but method seems like such a pain.
I also acknowledge that this may not be possible, but was curious if it is!
Thanks in advance!
It is totally possible to make a window which is above all other windows, just set It's level to NSMainMenuWindowLevel.
But preventing other windows from resizing beyond It, I don't think so.
Even if there is a system API to limit window resizing (I don't think there is), some apps use custom code to control window resizing and would completely ignore the presence of your "special" window. I've seen apps which simply hardcode 22 (the height of the menu bar) when calculating window resizing stuff.

Objective-C Lion Fullscreen use all monitors

We have 4 monitors on a wall for graphing. Looking to put them all into use in fullscreen mode. Right now if I do it it just uses one. Just looking to see if it is possible to create an app that allows me to use all 4 with like a simple uiwebview for each monitor.
Should of mentioned this.. Looking for a simple code sample of how to do this or pointers on where to get answers.
Yes, it is possible.
Standard Lion fullscreen mode allows for one "primary window", which is sized to take up the entire main screen, and as many "auxiliary windows" (inspector panels, etc.) as you want, which are not automatically sized in any way.
Go into Xcode, create a simple project, and edit the xib. For the existing window, go to the Attributes Inspector and make sure that Full Screen is set to "Primary Window". Now in the object browser, drag three Panels into the app. Go through them and make sure each one has "Utility Panel" for Style, "Auxiliary Window" for Full Screen, and either "Inferred Behavior" or "Transient Behavior" for Exposé. Now, when the first window goes into full screen mode (e.g., when you get the appropriate notification or NSWindowDelegate method), size and move the other three windows to take over the other three screens.
This is all documented pretty well in the Implementing the Full-Screen Experience section of the "Mac App Programming Guide" in the 10.7 Core Library.
If you're just looking to put a web view on each screen, it may be easier to use -[NSView enterFullScreenMode:withOptions:]. This isn't Lion's new full-screen mode, it's the earlier technique. It has different behavior in terms of whether the app is in a separate space, etc.

Showing ProgressBar over Desktop (Transparent Window) - Cocoa

Well, it might be hard to describe, but what I want this:
When the application fires up, I want it to load a couple of components and I want to show a progress bar loading upto 100% Complete. But for Interface sake, I just want the progress bar on the desktop. I don't want the Window controls or background. My customized progress bar should appear on the desktop loading upto 100%, followed by showing of window and thereby, the entire app.
Just to mention, I want this in a Mac App being developed in Xcode.
I strongly suggest you think about the visual effect you're considering and the assumptions you're making. I would argue this to be "bad design":
Users can put anything as a Desktop Picture. If my background happens to be blue... and your custom progress bar is blue.. then I won't see the progress bar and will be left wondering why your application isn't responding. "Screw this app, it hangs when I launch it. Delete!"
Chances are that users have more than one application running. Your "floating progress bar" would be lost in a sea of other application windows. (Why is iTunes loading something? Oh wait!! It's this other windowless thing... "Not intuitive! Not cool")
This is not very Mac-like. Don't forget there are rules for each platform as to how to be a good citizen. Metro apps need to adhere to a specific Interface paradigm. Likewise, there's a thing to be said for "Mac-like" and I would argue this behaviour isn't (a floating progress bar).
I would strongly suggest you keep your progress bar within a properly named modal window. Applications go in-and-out of being front-most... so it's important to know what that progress bar relates too.
If you've considered all these, the following question should help you get started :
How to make an NSView transparent and show what's under the NSWindow?
You are probably talking of a borderless NSWindow (NSBorderlessWindowMask), with an opaque background view whose alpha is set to zero and an NSProgressIndicator subview to show the progress. You also probably want to use the -[NSWindow center] method to nicely center your window.
However, I doubt that you want that kind of UI. A progress bar is probably not visible on top of all desktops, and thus aesthetically worthless.
I think a rounded, half-transparant black window will be more suited in your case. Take a look at Matt Gemmell's source code.

How can I check whether Exposé is being activated or not?

I'm creating an application that emulates MacBook's multi-touch Trackpad. As you may know, on MacBook's trackpad
if you swipe 4 fingers up, it triggers the Show Desktop.
if you swipe 4 fingers down, it shows the Exposé.
However, if the Show Desktop is being activated and you swipe 4 fingers down, it will come back to the normal mode. The same goes with the Exposé: if the Exposé is being activated and you swipe 4 fingers up, it will also come back to the normal mode.
Here is the problem: I use the keyboard shortcut F3 to show the Exposé and F11 to show the Show Desktop. The problem is, when the Show Desktop is being activated, if I press F3, it will go straight to the Exposé. And when the Exposé is being activated, if I press F11 it will go straight to the Show Desktop. But I want it to behave like Trackpad, which I guess its code may look like this
- FourFingersDidSwipeUp {
if (isExposeBeingActivated() || isShowDesktopBeingActivated()) {
pressKey("Esc");
} else {
pressKey("F11");
}
}
But I don't know how to implement the "isExposeBeingActivated()" and "isShowDesktopBeingActivated()" methods. I've tried creating a window and check whether its size has changed (on assumption that if the Expose is being activated, its size should be smaller), but the system always returns the same size. I tried monitoring the background processes during the Expose, but nothing happened. Does anyknow have any suggestions on this?
(I'm sorry if my English sounds weird.)
As far as I know, there's no public interface to any Exposé related functionality beyond the ability to specify the "collection behavior" of your own application's windows.
came here after reading your email. I understand the problem. After a bit of googling I found out what you already know, that there's really no official API or documentation for Exposé. A very ugly solution I've thought of could be having Exposé trigger a timer equal to the total time it takes to show all windows fully (guessing this is constant). If a swipe up would be done within that timer, it would mean that Exposé would still be active (isExposeBeingActivated()), so you would trigger a cancel instead of a Show Desktop. This wouldn't cover the use of the "slow motion" Exposé (via SHIFT key). Maybe you can detect if it's a normal or "slow motion" Exposé call?
Really sorry if this doesn't make sense at all within your application's scope, guess I'm just really saying the first solution I thought of.
Cheers.
Pedro.

Making a full screen Cocoa app

I want to create a full Screen Cocoa application, however my app is slightly different from a conventional fullscreen app.
This app would be below everything else, so underneath the menu bar and the Dock, etc. It would have a large image covering up the Desktop and icons, with a custom NSView in the middle with a table view, etc. If this concept is hard to understand then here is an image:
http://img10.imageshack.us/img10/6308/mockupo.png
The only part that might be a bit confusing is the background image. This background image is NOT the wallpaper of the computer, but part of the app. So when the app is launched, it goes into full screen mode and puts itself underneath the dock and the menu bar, and underneath all other windows too. So it draws the background image to cover the screen (including Desktop and icons). Then has a custom NSView in the middle containing my controls.
What's the best way to go about doing this?
Thanks
Make a borderless window, the size of the menu-bar screen (screen 0—not [NSScreen mainScreen]), positioned at 0,0, with window level kCGDesktopWindowLevel.
Remember that you will need to observe for screen frame-change notifications (when the user changes the screen dimensions), and that you should correctly handle the case of no screen at all (headless Mac).
I think #Peter Hosey’s solution should work, but to make other windows go on top, you will probably need to change the window level to something else.
But, I implore you, do not do this. This will be the most bugly application the Macintosh has ever seen. There are a lot of really good user interface paradigms that you can use, and "replicating" the main desktop interface of Mac OS X is generally not one of them. That is, unless you are reimplementing Time Machine or something like that.