ボタンに影をつける

button の layerに setShadow系のメソッドを呼べば良い。

- (void)addShadow:(UIButton*)button
{
     [button.layer setShadowColor:[[UIColor blackColor] CGColor]];
     [button.layer setShadowOffset:CGSizeMake(0, 3)];
     [button.layer setShadowOpacity:0.925];
     [button.layer setCornerRadius:3];
}

// 設置
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
btn.frame = CGRectMake(100, 150, 50, 30);
[self addShadow:btn];
[self.view addSubview:btn];