ios 如何解决警告：将 'ViewController *const __strong' 发送到不兼容类型 'id<AVAudioPlayerDelegate> 的参数？
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How to solve the warning: Sending 'ViewController *const __strong' to parameter of incompatible type 'id<AVAudioPlayerDelegate>?
提问by Jeremy L
The following code gave a warning of Sending 'ViewController *const __strong' to parameter of incompatible type 'id<AVAudioPlayerDelegate>'(it is the third line in the following code):
下面的代码给出了一个警告Sending 'ViewController *const __strong' to parameter of incompatible type 'id<AVAudioPlayerDelegate>'（它是下面代码中的第三行）：
NSURL *sound0URL = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"0" ofType:@"aiff"]];
audioPlayer0 = [[AVAudioPlayer alloc] initWithContentsOfURL:sound0URL error:nil];
[audioPlayer0 setDelegate: self]; // <--- this line causes the warning
[audioPlayer0 prepareToPlay];
audioPlayer0.currentTime = 0;
[audioPlayer0 play];
How can it be fixed? I have this code in the ViewController's instance method of viewDidLoad. There was another question similar but that was a class method: Incompatible pointer types assigning to 'id<AVAudioPlayerDelegate>' from 'Class'
如何修复？我在此代码ViewController的的实例方法viewDidLoad。还有另一个类似的问题，但这是一个类方法：不兼容的指针类型分配给 'id<AVAudioPlayerDelegate>' from 'Class'
回答by CodaFi
Conform to the AVAudioPlayerDelegateprotocol in your header file and the warning will go away. By not declaring that a class conforms to a given protocol, the compiler cannot guarantee (well, at least warn) about your failure to implement the methods required of it. The following code is a corrected version that will suppress the warning.
遵守AVAudioPlayerDelegate头文件中的协议，警告就会消失。通过不声明一个类符合给定的协议，编译器不能保证（好吧，至少警告）你没有实现它所需的方法。以下代码是将抑制警告的更正版本。
@interface ViewController : UIViewController <AVAudioPlayerDelegate>
@end
回答by Rajive Jain
Interestingly that didn't do it for me. I have the delegate defined in header file - working with UIImagePickerControllerDelegatein a UITableViewController. Since setDelegate method expected an id, I set delegate as follows instead:
有趣的是，这并不适合我。我在头文件中定义了委托 -在UITableViewController 中使用UIImagePickerControllerDelegate。由于 setDelegate 方法需要一个 id，我改为如下设置委托：
[myImagePicker setDelegate: (id)self];
But I would like to know what's happening here ? Since this is not normally showing itself in other delegate examples in other areas of code. Could anyone elucidate on this ?
但我想知道这里发生了什么？因为这通常不会出现在其他代码区域的其他委托示例中。任何人都可以阐明这一点吗？
Thanks
谢谢
回答by Pochi
Your self (your class) doesnt have the
你的自我（你的班级）没有
@interface MyClassName: NSObject <AVAudioPlayerDelegate>
in the header file.
在头文件中。
回答by Kirit Vaghela
This is a warning telling you that you are missed to define your delegate in .h file
这是一个警告，告诉您您错过了在 .h 文件中定义您的委托
@interface ClassName : NSObject <YourDelegate>
回答by sourabh sharotria
Make sure you adding delegate inside UIComponent braces
确保在 UIComponent 大括号内添加委托
Eg: @interface DemoView : UIView < UITableViewDelegate>
例如：@interface DemoView : UIView < UITableViewDelegate>
rather than delegate property you are creating.
而不是委托您正在创建的财产。
@property(retain)id < UITableViewDelegate> demoDelegate
@property(retain)id < UITableViewDelegate> demoDelegate
