How do I create a Cocoa window programmatically?

Question

My Cocoa app needs some small dynamically generated windows. How can I programmatically create Cocoa windows at runtime?

This is my non-working attempt so far. I see no result whatsoever.

NSRect frame = NSMakeRect(0, 0, 200, 200);
NSUInteger styleMask =    NSBorderlessWindowMask;
NSRect rect = [NSWindow contentRectForFrameRect:frame styleMask:styleMask];

NSWindow * window =  [[NSWindow alloc] initWithContentRect:rect styleMask:styleMask backing: NSBackingStoreRetained    defer:false];
[window setBackgroundColor:[NSColor blueColor]];
[window display];

Answer 1

The problem is that you don't want to call display , you want to call either makeKeyAndOrderFront or orderFront depending on whether or not you want the window to become the key window. You should also probably use NSBackingStoreBuffered .

This code will create your borderless, blue window at the bottom left of the screen:

NSRect frame = NSMakeRect(0, 0, 200, 200);
NSWindow* window  = [[[NSWindow alloc] initWithContentRect:frame
                    styleMask:NSBorderlessWindowMask
                    backing:NSBackingStoreBuffered
                    defer:NO] autorelease];
[window setBackgroundColor:[NSColor blueColor]];
[window makeKeyAndOrderFront:NSApp];

//Don't forget to assign window to a strong/retaining property!
//Under ARC, not doing so will cause it to disappear immediately;
//  without ARC, the window will be leaked.

You can make the sender for makeKeyAndOrderFront or orderFront whatever is appropriate for your situation.

Answer 2

A side note, if you want to programatically instantiate the application without a main nib, in the main.m file / you can instantiate the AppDelegate as below. Then in your apps Supporting Files / YourApp.plist Main nib base file / MainWindow.xib delete this entry. Then use Jason Coco's approach to attach the window in your AppDelegates init method.

#import "AppDelegate.h":

int main(int argc, char *argv[])
{

  NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
  [NSApplication sharedApplication];

  AppDelegate *appDelegate = [[AppDelegate alloc] init];
  [NSApp setDelegate:appDelegate];
  [NSApp run];
  [pool release];
  return 0;
}

Answer 3

Try

[window makeKeyAndOrderFront:self]; 

instead of

[window display];

Is that what you're aiming for?

Answer 4

Translating the top rated answer to modern swift (5) gives you something akin to this:

var mainWindow: NSWindow!

...

mainWindow = NSWindow(
    contentRect: NSMakeRect(0, 0, 200, 200),
    styleMask: [.titled, .resizable, .miniaturizable, .closable],
    backing: .buffered,
    defer: false)
mainWindow.backgroundColor = .blue
mainWindow.makeKeyAndOrderFront(mainWindow)

Answer 5

This is what I've come up with myself:

NSRect frame = NSMakeRect(100, 100, 200, 200);
NSUInteger styleMask =    NSBorderlessWindowMask;
NSRect rect = [NSWindow contentRectForFrameRect:frame styleMask:styleMask];
NSWindow * window =  [[NSWindow alloc] initWithContentRect:rect styleMask:styleMask backing: NSBackingStoreBuffered    defer:false];
[window setBackgroundColor:[NSColor blueColor]];
[window makeKeyAndOrderFront: window];

This displays a blue window. I hope this is the optimal approach.