CODEWITHSUNDEEP
cocoainterface-buildernswindowcentering
Kaji
Kaji

Reputation: 2340

Centering Windows on screen

Short and sweet: How can I tell Interface Builder to center a window on a user's screen? I've seen the positioning tool on the inspector, but eyeballing doesn't always land as squarely as I like. Is this something where I should switch over to Xcode and add something to the init or awakeFromNib methods?

Upvotes: 6

Views: 6210

Answers (5)

ozgrozer
ozgrozer

Reputation: 2042

I was working on a React Native MacOS project and had to center the window but the [self.window center]; approach only works for horizontally, not vertically. So one of the comments made me realize that we can also center it by getting the screen size and subtracting the app width then dividing by two. So here's a working version.

AppDelegate.mm

- (void)applicationDidFinishLaunching:(NSNotification *)notification
{
  // You can add your custom initial props in the dictionary below.
  // They will be passed down to the ViewController used by React Native.
  self.initialProps = @{};

  // Call the super method to continue application launch
  [super applicationDidFinishLaunching:notification];

  // Define window width and height
  CGFloat windowWidth = 1000;
  CGFloat windowHeight = 600;

  // Get screen size
  NSScreen *screen = [NSScreen mainScreen];
  NSRect screenRect = [screen frame];

  // Calculate the center position
  CGFloat xPos = (screenRect.size.width - windowWidth) / 2;
  CGFloat yPos = (screenRect.size.height - windowHeight) / 2;

  // Set the initial window size and position here
  NSRect frame = NSMakeRect(xPos, yPos, windowWidth, windowHeight);
  [self.window setFrame:frame display:YES];

  // Make sure the window is initialized and displayed before centering
  [self.window makeKeyAndOrderFront:nil];
}

Upvotes: 0

Alexandre Cassagne
Alexandre Cassagne

Reputation: 2463

Use [window center]; for the centre of the window to be centred to the screen. Also, assuming you're in 10.5+, there is a centre to screen button in Interface Builder.

Upvotes: 7

neowinston
neowinston

Reputation: 7764

For macOS Mojave this worked for me, in AppDelegate applicationDidFinishLaunching for the Main Window:

[[[NSApplication sharedApplication] mainWindow] center];

Upvotes: 0

Abizern
Abizern

Reputation: 150685

You could use [window center] as answered by wahkiz, but that might not be exactly what you want. The documentation states that this will put the window centered horizontally, but somewhat above the vertical centre. In this way the window has a visual prominence.

If you want to put your window in the exact centre, then manual positioning (as commented by Koning Baard XIV) will work for you.

Upvotes: 15

wahkiz
wahkiz

Reputation: 616

In your appdelegate, in applicationfinishedlaunching, add this code at the bottom.

[window center];

Upvotes: 3

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