ios - 在 iOS 中使用 Core Graphics 创建渐变

Question

我有以下代码来创建渐变(或渐变的开始):

CAGradientLayer *gradient = [CAGradientLayer layer];


UIColor *lightGreen = [UIColor colorWithRed:66.0f/255.0f green:79.0f/255.0f blue:91.0f/255.0f alpha:1.0f];
UIColor *darkGreen = [UIColor colorWithRed:66.0f/255.0f green:79.0f/255.0f blue:91.0f/255.0f alpha:1.0f];

为什么这一行给我“预期标识符”？

gradient.colors = [NSArray arrayWithObjects:(id)[lightGreen.CGColor]];

Answer 1

你的代码中有很多 [ 并且你没有以 , nil 结束:

gradient.colors = [NSArray arrayWithObjects:(id)[lightGreen.CGColor]];

应该是:

gradient.colors = [NSArray arrayWithObjects:(id)lightGreen.CGColor, nil];

或者甚至:

gradient.colors = @[(id)lightGreen.CGColor];