Question

I have a button and I’m using CGRectMake to position it like this:

btn5.frame = CGRectMake(211, 280, 109, 60);

I guess 211 and 280 are the coordinates of the button. So how can I modify that code if I want the button to be near the bottom left corner.

Answer 1

Yes, you are correct. The frame of the button defines where it is located on its parent view. So btn5 will be in the position (x = 211, y = 280) and will have the dimensions (width = 109, hight = 60) if you use this code:

btn5.frame = CGRectMake(211, 280, 109, 60);

The general expression is:

btn5.frame = CGRectMake(buttonX, buttonY, buttonWidth, buttonHeight);

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If you want to change the position of the button to the bottom left corner, you can do like this:

btn5.frame = CGRectMake(0, self.view.frame.size.height - 60, 109, 60);

If you want to add some space between the button and the corner, and also change the size of the button:

CGFloat x = leftPadding;
CGFloat y = self.frame.size.width - desiredHeight - bottomPadding;
btn5.frame = CGRectMake(x, y, desiredWidth, desiredHeight); 

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For more information, check Apple’s View Geometry and Coordinate Systems guide.