DatePicker 设置字体颜色
[self.datePicker setValue:RGBCOLOR(204, 204, 204) forKey:@"textColor"];
// 默认选中的颜色 为黑色 修改方法如下
//通过NSSelectorFromString获取setHighlightsToday方法
SEL selector= NSSelectorFromString(@"setHighlightsToday:");
//创建NSInvocation
NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[UIDatePicker instanceMethodSignatureForSelector:selector]];
BOOL no = NO;
[invocation setSelector:selector];
//setArgument中第一个参数的类picker,第二个参数是SEL,
[invocation setArgument:&no atIndex:2];
//让invocation执行setHighlightsToday方法
[invocation invokeWithTarget:self.datePicker];