- (void)viewDidLoad {
  [super viewDidLoad];
  [self.view addSubview:self.dragView];
}
//創(chuàng)建View
-(UIView *)dragView{
  if (!_dragView) {
    _dragView = [[UIView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
    _dragView.backgroundColor = [UIColor redColor];
    [_dragView addInteraction:self.dragInteraction];
  }
  return _dragView;
}
//創(chuàng)建拖拽行為對象
-(UIDragInteraction *)dragInteraction{
  if (!_dragInteraction) {
    _dragInteraction = [[UIDragInteraction alloc]initWithDelegate:self];
    //要設置可用 注意?。?！
    [_dragInteraction setEnabled:YES];
  }
  return _dragInteraction;
}

//實現(xiàn)提供數(shù)據(jù)的代理方法
- (NSArray<UIDragItem *> *)dragInteraction:(UIDragInteraction *)interaction itemsForBeginningSession:(id<UIDragSession>)session{
  //數(shù)據(jù)提供者
  NSItemProvider * provider = [[NSItemProvider alloc]initWithObject:@"Hello World"];
  UIDragItem * item = [[UIDragItem alloc]initWithItemProvider:provider];
  return @[item];
}

//初始化方法
- (instancetype)initWithDelegate:(id<UIDragInteractionDelegate>)delegate;
//代理
@property (nonatomic, nullable, readonly, weak) id<UIDragInteractionDelegate> delegate;
//是否支持多種手勢都接收響應
@property (nonatomic) BOOL allowsSimultaneousRecognitionDuringLift;
//設置是否有效
@property (nonatomic, getter=isEnabled) BOOL enabled;
//獲取默認是否有效 不同的設備這個值將有所區(qū)別
@property (class, nonatomic, readonly, getter=isEnabledByDefault) BOOL enabledByDefault;

/*
這個方法是必須實現(xiàn)的用來返回拖拽源提供的數(shù)據(jù)
需要注意，這個函數(shù)需要返回一個數(shù)組，數(shù)組中可以有多個數(shù)據(jù)源
如果返回空數(shù)組，則拖拽行為不會開始
*/
- (NSArray<UIDragItem *> *)dragInteraction:(UIDragInteraction *)interaction itemsForBeginningSession:(id<UIDragSession>)session;
/*
這個方法用來自定義拖拽效果的預覽視圖 關于預覽視圖，后面會介紹
需要注意，系統(tǒng)默認會提供一個預覽視圖，不實現(xiàn)這個方法即是使用系統(tǒng)默認的
如果返回nil，則會去除預覽動畫
*/
- (nullable UITargetedDragPreview *)dragInteraction:(UIDragInteraction *)interaction previewForLiftingItem:(UIDragItem *)item session:(id<UIDragSession>)session;
/*
拖拽動畫即將開始時會調(diào)用此函數(shù)
*/
- (void)dragInteraction:(UIDragInteraction *)interaction willAnimateLiftWithAnimator:(id<UIDragAnimating>)animator session:(id<UIDragSession>)session;
//拖拽行為會話即將開始時調(diào)用的方法
- (void)dragInteraction:(UIDragInteraction *)interaction sessionWillBegin:(id<UIDragSession>)session;
//這個方法設置數(shù)據(jù)的防止是否允許數(shù)據(jù)的 移動操作，需要注意，這個只有在app內(nèi)有效，跨app的操作會總是復制數(shù)據(jù)
- (BOOL)dragInteraction:(UIDragInteraction *)interaction sessionAllowsMoveOperation:(id<UIDragSession>)session;
//設置是否允許跨應用程序進行拖拽 ipad
- (BOOL)dragInteraction:(UIDragInteraction *)interaction sessionIsRestrictedToDraggingApplication:(id<UIDragSession>)session;
//設置預覽視圖是否顯示原始大小
- (BOOL)dragInteraction:(UIDragInteraction *)interaction prefersFullSizePreviewsForSession:(id<UIDragSession>)session;
/*
當拖拽源被移動時調(diào)用，可以用如下方法獲取其坐標
NSLog(@"%f,%f",[session locationInView:self.view].x,[session locationInView:self.view].y);
*/
- (void)dragInteraction:(UIDragInteraction *)interaction sessionDidMove:(id<UIDragSession>)session;
//拖拽行為將要結(jié)束時調(diào)用
- (void)dragInteraction:(UIDragInteraction *)interaction session:(id<UIDragSession>)session willEndWithOperation:(UIDropOperation)operation;
//拖拽行為已經(jīng)結(jié)束時調(diào)用
- (void)dragInteraction:(UIDragInteraction *)interaction session:(id<UIDragSession>)session didEndWithOperation:(UIDropOperation)operation;
//拖拽源進行了放置操作后調(diào)用
- (void)dragInteraction:(UIDragInteraction *)interaction sessionDidTransferItems:(id<UIDragSession>)session;
//設置拖拽動作取消的視圖動畫 返回nil則消除動畫
-(nullable UITargetedDragPreview *)dragInteraction:(UIDragInteraction *)interaction previewForCancellingItem:(UIDragItem *)item withDefault:(UITargetedDragPreview *)defaultPreview;
//拖拽動作即將取消時調(diào)用的方法
- (void)dragInteraction:(UIDragInteraction *)interaction item:(UIDragItem *)item willAnimateCancelWithAnimator:(id<UIDragAnimating>)animator;
//設置是否允許向拖拽中的項目添加數(shù)據(jù)
/*
可以返回數(shù)據(jù)載體數(shù)組 當拖拽過程中 點擊可拖拽的組件時會觸發(fā)
*/
- (NSArray<UIDragItem *> *)dragInteraction:(UIDragInteraction *)interaction itemsForAddingToSession:(id<UIDragSession>)session withTouchAtPoint:(CGPoint)point;
//設置允許進行拖拽中追加數(shù)據(jù)的拖拽行為會話
- (nullable id<UIDragSession>)dragInteraction:(UIDragInteraction *)interaction sessionForAddingItems:(NSArray<id<UIDragSession>> *)sessions withTouchAtPoint:(CGPoint)point;
//將要向拖拽組件中追加數(shù)據(jù)時調(diào)用
- (void)dragInteraction:(UIDragInteraction *)interaction session:(id<UIDragSession>)session willAddItems:(NSArray<UIDragItem *> *)items forInteraction:(UIDragInteraction *)addingInteraction;

//添加視圖
- (void)viewDidLoad {
  [super viewDidLoad];
  //有關拖拽源的代碼 前面已經(jīng)列舉過 這里不再重復
  [self.view addSubview:self.dragView];
  [self.view addSubview:self.dropLabel];
}

-(UILabel *)dropLabel{
  if (!_dropLabel) {
    _dropLabel = [[UILabel alloc]initWithFrame:CGRectMake(10, 300, 300, 30)];
    _dropLabel.backgroundColor = [UIColor greenColor];
    _dropLabel.userInteractionEnabled = YES;
    [_dropLabel addInteraction:self.dropInteraction];
  }
  return _dropLabel;
}
//放置目的地行為對象
-(UIDropInteraction*)dropInteraction{
  if (!_dropInteraction) {
    _dropInteraction = [[UIDropInteraction alloc]initWithDelegate:self];
  }
  return _dropInteraction;
}

//這個方法返回是否響應此放置目的地的放置請求
-(BOOL)dropInteraction:(UIDropInteraction *)interaction canHandleSession:(id<UIDropSession>)session{
  return YES;
}
//設置以何種方式響應拖放會話行為
-(UIDropProposal *)dropInteraction:(UIDropInteraction *)interaction sessionDidUpdate:(id<UIDropSession>)session{
  return [[UIDropProposal alloc]initWithDropOperation:UIDropOperationCopy];
}
//已經(jīng)應用拖放行為后執(zhí)行的操作
-(void)dropInteraction:(UIDropInteraction *)interaction performDrop:(id<UIDropSession>)session{ 
  [session loadObjectsOfClass:[NSString class] completion:^(NSArray<__kindof id<NSItemProviderReading>> * _Nonnull objects) {
    self.dropLabel.text = objects.firstObject;
  }];
}

//初始化方法
- (instancetype)initWithDelegate:(id<UIDropInteractionDelegate>)delegate;
//代理對象
@property (nonatomic, nullable, readonly, weak) id<UIDropInteractionDelegate> delegate;
//是否允許多個交互行為
@property (nonatomic, assign) BOOL allowsSimultaneousDropSessions;

//放置行為即將響應時觸發(fā)的方法 返回值確定是否響應此次行為
- (BOOL)dropInteraction:(UIDropInteraction *)interaction canHandleSession:(id<UIDropSession>)session;
//當上面的協(xié)議方法返回YES時會接著調(diào)用這個函數(shù)
- (void)dropInteraction:(UIDropInteraction *)interaction sessionDidEnter:(id<UIDropSession>)session;
//將要處理數(shù)據(jù)時回調(diào)的方法
/*
當數(shù)據(jù)源數(shù)據(jù)添加時，這個方法也會被重新調(diào)用 
這個函數(shù)需要返回一個處理行為方式UIDropProposal對象，這個我們后面再說
*/
- (UIDropProposal *)dropInteraction:(UIDropInteraction *)interaction sessionDidUpdate:(id<UIDropSession>)session;
//放置行為相應結(jié)束的時候會調(diào)用此方法
- (void)dropInteraction:(UIDropInteraction *)interaction sessionDidExit:(id<UIDropSession>)session;
//這個方法當用戶進行放置時會調(diào)用，可以從session中獲取被傳遞的數(shù)據(jù)
- (void)dropInteraction:(UIDropInteraction *)interaction performDrop:(id<UIDropSession>)session;
//放置動畫完成后會調(diào)用這個方法
- (void)dropInteraction:(UIDropInteraction *)interaction concludeDrop:(id<UIDropSession>)session;
//整個拖放行為結(jié)束后會調(diào)用
- (void)dropInteraction:(UIDropInteraction *)interaction sessionDidEnd:(id<UIDropSession>)session;
//下面這些方法用來自定義放置動畫
//設置放置預覽動畫
- (nullable UITargetedDragPreview *)dropInteraction:(UIDropInteraction *)interaction previewForDroppingItem:(UIDragItem *)item withDefault:(UITargetedDragPreview *)defaultPreview;
//這個函數(shù)每當有一個拖拽數(shù)據(jù)項放入時都會調(diào)用一次 可以進行動畫
- (void)dropInteraction:(UIDropInteraction *)interaction item:(UIDragItem *)item willAnimateDropWithAnimator:(id<UIDragAnimating>)animator;

//初始化方法
/*
typedef NS_ENUM(NSUInteger, UIDropOperation) {
  //取消這次行為
  UIDropOperationCancel  = 0,
  //拒絕行為
  UIDropOperationForbidden = 1,
  //接收拷貝數(shù)據(jù)
  UIDropOperationCopy   = 2,
  //接收移動數(shù)據(jù)
  UIDropOperationMove   = 3,
}
*/
- (instancetype)initWithDropOperation:(UIDropOperation)operation;
//處理方式
@property (nonatomic, readonly) UIDropOperation operation;
//精準定位
@property (nonatomic, getter=isPrecise) BOOL precise;
//設置是否展示完整的預覽尺寸
@property (nonatomic) BOOL prefersFullSizePreview;

//初始化方法
- (instancetype)initWithItemProvider:(NSItemProvider *)itemProvider;
//數(shù)據(jù)提供者實例
@property (nonatomic, readonly) __kindof NSItemProvider *itemProvider;
//用來傳遞一些額外的關聯(lián)信息
@property (nonatomic, strong, nullable) id localObject;
//用來自定義每個item添加時的預覽動畫
@property (nonatomic, copy, nullable) UIDragPreview * _Nullable (^previewProvider)(void);

//繼承于UIDragDropSession(提供基礎數(shù)據(jù)), NSProgressReporting(提供數(shù)據(jù)讀取進度)
@protocol UIDropSession <UIDragDropSession, NSProgressReporting>
//原始的dragSesstion會話 如果是跨應用的 則為nil
@property (nonatomic, readonly, nullable) id<UIDragSession> localDragSession;
//設置進度風格
/*
typedef NS_ENUM(NSUInteger, UIDropSessionProgressIndicatorStyle) {
  UIDropSessionProgressIndicatorStyleNone,    // 無
  UIDropSessionProgressIndicatorStyleDefault,  // 默認的
} API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos);
*/
@property (nonatomic) UIDropSessionProgressIndicatorStyle progressIndicatorStyle;
//進行數(shù)據(jù)的加載
- (NSProgress *)loadObjectsOfClass:(Class<NSItemProviderReading>)aClass completion:(void(^)(NSArray<__kindof id<NSItemProviderReading>> *objects))completion;
@end

API_AVAILABLE(ios(11.0)) API_UNAVAILABLE(watchos, tvos) @protocol UIDragSession <UIDragDropSession>
//設置要傳遞的額外信息 只有在同個APP內(nèi)可見
@property (nonatomic, strong, nullable) id localContext;
@end

//傳遞的數(shù)據(jù)數(shù)組
@property (nonatomic, readonly) NSArray<UIDragItem *> *items;
//當前操作行為的坐標
- (CGPoint)locationInView:(UIView *)view;
//此次行為是否允許移動操作
@property (nonatomic, readonly) BOOL allowsMoveOperation;
//是否支持應用程序?qū)用娴耐献?
@property (nonatomic, readonly, getter=isRestrictedToDraggingApplication) BOOL restrictedToDraggingApplication;
//驗證傳遞的數(shù)據(jù)是否支持某個數(shù)據(jù)類型協(xié)議
- (BOOL)hasItemsConformingToTypeIdentifiers:(NSArray<NSString *> *)typeIdentifiers;
//驗證傳遞的數(shù)據(jù)是否可以加載某個類
- (BOOL)canLoadObjectsOfClass:(Class<NSItemProviderReading>)aClass;

//創(chuàng)建一個預覽對象 
/*
view：要創(chuàng)建的預覽視圖 需要注意，這個視圖必須在window上
param：配置參數(shù)
target：容器視圖，用來展示預覽，一般設置為view的父視圖
*/
- (instancetype)initWithView:(UIView *)view parameters:(UIDragPreviewParameters *)parameters target:(UIDragPreviewTarget *)target;
//同上
-(instancetype)initWithView:(UIView *)view parameters:(UIDragPreviewParameters *)parameters;
//同上
- (instancetype)initWithView:(UIView *)view;
//動畫承載者
@property (nonatomic, readonly) UIDragPreviewTarget* target;
//動畫視圖
@property (nonatomic, readonly) UIView *view;
//配置參數(shù)
@property (nonatomic, readonly, copy) UIDragPreviewParameters *parameters;
//尺寸
@property (nonatomic, readonly) CGSize size;
//返回新的對象
- (UITargetedDragPreview *)retargetedPreviewWithTarget:(UIDragPreviewTarget *)newTarget;

/*
初始化方法
container：必須是在window上的view
center：動畫起點與終點
transform:進行變換
*/
- (instancetype)initWithContainer:(UIView *)container center:(CGPoint)center transform:(CGAffineTransform)transform;
//同上
- (instancetype)initWithContainer:(UIView *)container center:(CGPoint)center;
//對應屬性
@property (nonatomic, readonly) UIView *container;
@property (nonatomic, readonly) CGPoint center;
@property (nonatomic, readonly) CGAffineTransform transform;

//構造方法并設置路徑矩形
- (instancetype)initWithTextLineRects:(NSArray<NSValue /* CGRect */ *> *)textLineRects;
//顯示的路徑
@property (nonatomic, copy, nullable) UIBezierPath *visiblePath;
//背景色
@property (nonatomic, copy, null_resettable) UIColor *backgroundColor;

#import <Foundation/Foundation.h>
//遵守協(xié)議
@interface Person : NSObject<NSItemProviderWriting,NSItemProviderReading>
//自定義內(nèi)容
@property(nonatomic,strong)NSString * name;
@property(nonatomic,assign)NSUInteger age;
@end

//.m文件
@implementation Person
//數(shù)據(jù)歸檔
- (nullable NSProgress *)loadDataWithTypeIdentifier:(NSString *)typeIdentifier
          forItemProviderCompletionHandler:(void (^)(NSData * _Nullable data, NSError * _Nullable error))completionHandler{
  NSProgress * pro = [NSProgress new];
  NSData * data = [NSKeyedArchiver archivedDataWithRootObject:self];
  completionHandler(data,nil);
  return pro;
}

+(NSItemProviderRepresentationVisibility)itemProviderVisibilityForRepresentationWithTypeIdentifier:(NSString *)typeIdentifier{
  return NSItemProviderRepresentationVisibilityAll;
}

- (NSItemProviderRepresentationVisibility)itemProviderVisibilityForRepresentationWithTypeIdentifier:(NSString *)typeIdentifier{
  return NSItemProviderRepresentationVisibilityAll;
}
//提供一個標識符
+(NSArray<NSString *> *)writableTypeIdentifiersForItemProvider{
  return @[@"object"];
}
-(NSArray<NSString *> *)writableTypeIdentifiersForItemProvider{
  return @[@"object"];
}

- (instancetype)initWithCoder:(NSCoder *)coder
{
  self = [super init];
  if (self) {
    self.name = [coder decodeObjectForKey:@"name"];
    self.age = [coder decodeIntegerForKey:@"age"];
  }
  return self;
}

- (void)encodeWithCoder:(NSCoder *)aCoder{
  [aCoder encodeObject:self.name forKey:@"name"];
  [aCoder encodeInteger:self.age forKey:@"age"];
}
//這兩個是讀協(xié)議
+(NSArray<NSString *> *)readableTypeIdentifiersForItemProvider{
  return @[@"object"];
}
//解歸檔返回
+ (nullable instancetype)objectWithItemProviderData:(NSData *)data
                   typeIdentifier:(NSString *)typeIdentifier
                       error:(NSError **)outError{
  Person * p = [NSKeyedUnarchiver unarchiveObjectWithData:data];
  return p;
}
@end

-(void)dropInteraction:(UIDropInteraction *)interaction performDrop:(id<UIDropSession>)session{
  NSLog(@"%@",session.items.lastObject.localObject);
  [session loadObjectsOfClass:[Person class] completion:^(NSArray<__kindof id<NSItemProviderReading>> * _Nonnull objects) {
    self.dropLabel.text = ((Person*)objects.firstObject).name;
  }];
}