将UIButton标题居中

Question

I want to center (both x and y axis) this + sign within my UIButton CGRect but it keeps getting pushed down the y-axis.

UIButton *aButton = [UIButton buttonWithType:UIButtonTypeSystem];
[aButton setTitle:@"+" forState:UIControlStateNormal];
[aButton.titleLabel setFont:[UIFont fontWithName:@"HelveticaNeue-Bold" size:(40.0)]];
[aButton setBackgroundColor:[UIColor grayColor]];
[aButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
[aButton setTitleColor:[UIColor blueColor] forState:UIControlStateHighlighted];

aButton.layer.cornerRadius = 25.0;

aButton.frame = CGRectMake(75.0, 100.0, 50.0, 50.0);

Answer 1

This would look more correct to you if you had ascenders and descenders. There's a label inside the button and it is sized to accommodate the height of the full range of possible characters of this font. If you don't like the position of the label, you're free to move it. There are a lot of ways to do this; you might try playing with the button's titleEdgeInsets , for example.

Answer 2

设置标题和字体后添加以下行：

aButton.titleEdgeInsets = UIEdgeInsetsMake(0, 0, 9, 0);