Cocoa Webkit WebPolicyDecisionListener錯誤實現

Question

我正在用Cocoa Webkit開發OS X上的應用程序。 我已經實現了我的自定義WebPolicyDecisionListener，但我得到了休耕錯誤：

Class WebPolicyDecisionListener is implemented in both /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit and /Users/cagryInside/Library/Developer/Xcode/DerivedData/MacKeep-aejgqnnxruvgutahmyngzygezfse/Build/Products/Debug/MacKeep.app/Contents/MacOS/MacKeep. One of the two will be used. Which one is undefined.

這裏是我的代碼：

WebPolicyDecisionListener* listener = [[WebPolicyDecisionListener alloc] init]; 
[[self webView] setPolicyDelegate:listener]; 

感謝您的幫助。

Answer 1

WebPolicyDecisionListener是協議。您不需要直接實例化它，您需要創建自己的類，聲明符合WebPolicyDecisionListener，並實現所需的方法。

如果您不熟悉使用協議，請參閱Programming with Objective-C: Working with Protocols。