iPhone漸變按鈕問題

Question

我有以下代碼來創建漸變按鈕：

CAGradientLayer *gradientLayer = [CAGradientLayer layer]; 
gradientLayer.frame = btnSignUp.layer.bounds; 

gradientLayer.colors = [NSArray arrayWithObjects: 
         (id)[UIColor colorWithWhite:1.0f alpha:0.1f].CGColor, 
         (id)[UIColor colorWithWhite:0.4f alpha:0.5f].CGColor, 
         nil]; 

gradientLayer.cornerRadius = btnSignUp.layer.cornerRadius; 

[btnSignUp.layer addSublayer:gradientLayer]; 

然而，底部圓角都畫滿了。我無法弄清楚爲什麼會發生這種情況。有任何想法嗎？

這裏是圖片：http://imageshack.us/a/img546/509/btnw.png

Answer 1

如果你的目標的iOS 5.0或更高版本，您可能需要創建漸變的PNG文件和伸展它來填充，而不是用層搞亂按鈕的背景。我相信使用PNG的性能影響更好。

因此，像：

static UIEdgeInsets insets = {15, 15, 15, 15}; (or whatever your insets are) 
UIImage* image = [[UIImage imageNamed:@"myImage"] resizableImageWithCapInsets:insets]; 
[_button setBackgroundImage:image forState:UIControlStateNormal]; 

Answer 2

我想你想要的是_button.layer.masksToBounds = YES;