ios - 类不符合 NSItemProviderWriting 协议(protocol) - Objective-C

Question

创建了一个实现 NSItemProviderWriting 的类

它给出警告为:

1.Class 'DraggableEvent' does not conform to protocol 'NSItemProviderWriting'
2.Class property 'writableTypeIdentifiersForItemProvider' requires method 'writableTypeIdentifiersForItemProvider' to be defined - use @dynamic or provide a method implementation in this class implementation

代码:DraggableEvent.h

#import <Foundation/Foundation.h>

@interface DraggableEvent : NSObject <NSItemProviderWriting>
{

}

可拖动事件.m
@implementation DraggableEvent

@synthesize writableTypeIdentifiersForItemProvider;

-(void)setWritableTypeIdentifiersForItemProvider:
(NSArray*)writableTypeIdentifiersForItemProvider{

 }
 -(NSArray*)writableTypeIdentifiersForItemProvider{
   writableTypeIdentifiersForItemProvider = [[NSArray 
   alloc]initWithObjects:@"com.apple.ical.ics", nil];
   return writableTypeIdentifiersForItemProvider;
  }


  - (nullable NSProgress *)loadDataWithTypeIdentifier:(NSString 
  *)typeIdentifier
               forItemProviderCompletionHandler:(void (^)(NSData * 
   _Nullable data, NSError * _Nullable error))completionHandler{
    completionHandler([self createVEvent], nil);
    return nil;
   }

Answer 1

我想通了。

请注意，该属性是类属性。
@property (class, NS_NONATOMIC_IOSONLY, readonly, copy) NSArray<NSString *> *readableTypeIdentifiersForItemProvider;

所以我们应该使用
+ (NSArray<NSString *> *)writableTypeIdentifiersForItemProvider;
+ (NSArray<NSString *> *)readableTypeIdentifiersForItemProvider;

代替 -

看下面这个问题

How to implement @property(class, readonly, copy, nonatomic) NSArray<NSString *> * _Nullable readableTypeIdentifiersForItemProvider;