按钮上文字位置

//按钮标题

[button setTitle:@"Hello World!" forState:UIControlStateNormal];

//button上子控件的水平对齐方式

button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;

//button上子控件的垂直对齐方式

button.contentVerticalAlignment = UIControlContentVerticalAlignmentTop;

//内容容器的偏移，让文字向右偏移20像素

button.contentEdgeInsets = UIEdgeInsetsMake(0,20, 0, 0);