Problem with Position of NSWindow after changing the ContenView

in my application i hav one NSWindow and different CustomViews... my target is just to change the contenView of the window. i placed the main window in the center of the screen with a button and after pressing the button the following code is executed

[mainWindow setFrame:[mainView frame] display:TRUE animate:TRUE];
[mainWindow setContentView:mainView];

this just works fine but after resizing the window is in the left bottom corner of the screen.. i want it to stay in the center of the screen

when i use

[mainWindow center];

it will move 开发者_运维问答to the left bottom corner and after resizing it jumps to to center.. that not good at all it should just stay in the middle of the screen

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The reason your window moves to the bottom-left corner is that [mainWindow setFrame:[mainView frame] display:YES animate:YES]; The [mainView frame].origin is NSZeroPoint while it has no superview. If you want your window to stay centered, you need to setFrameOrigin:. I recommend using NSMidX() and NSMidY() to calculate the offset from the screen's center.