关于swift中出现 use of undeclared type ***错误的一种解决方法

最新推荐文章于 2025-07-04 12:56:36 发布

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当Swift代码遇到use of undeclared type错误，可能是类名与协议方法名冲突导致。例如，OC的UCSPasswordViewDelegate协议中，'UCSPasswordView'方法名与类名相同，造成冲突。在Swift里，可以调整方法名避免冲突或使用别名来解决此问题。

出现这种错误可能因为类名跟函数名冲突，特别是在出现代理的时候，例如

#import <UIKit/UIKit.h>

@class UCSPasswordView;

@protocol UCSPasswordViewDelegate <NSObject>

#pragma mark - 输入完回掉

- (void)UCSPasswordView:(UCSPasswordView *)passwordView withPassword:(id)password;

#pragma mark-- 输入不符合格式的

@end

@interface UCSPasswordView : UIView

@property (nonatomic,weak) id<UCSPasswordViewDelegate> delegate;

@end

用swift遵守上面OC写的协议时肯定在在swift处报use of undeclared type ***错。因为Delegate里面的方法UCSPasswordView跟类名UCSPasswordView冲突了。以下这句话引自stackoverflow的回答：（http://stackoverflow.com/questions/24627598/use-of-undeclared-type-in-swift-project）

Your delegate function name is VKConnector and you also have a class named VKConnector. That's your conflict. In Objective C your delegate method is VKConnector:withBool: but in Swift it's simply VKConnector and withBool is not a part of the name.