中文字幕理论片,69视频免费在线观看,亚洲成人app,国产1级毛片,刘涛最大尺度戏视频,欧美亚洲美女视频,2021韩国美女仙女屋vip视频

 （1）取消隊列的所有操作

 - (void)cancelAllOperations;

提?:也可以調用NSOperation的- (void)cancel?法取消單個操作

 （2）暫停和恢復隊列

- (void)setSuspended:(BOOL)b; // YES代表暫停隊列,NO代表恢復隊列

- (BOOL)isSuspended; //當前狀態(tài)

 （1）設置NSOperation在queue中的優(yōu)先級,可以改變操作的執(zhí)?優(yōu)先級

- (NSOperationQueuePriority)queuePriority;
- (void)setQueuePriority:(NSOperationQueuePriority)p;

 （2）優(yōu)先級的取值

NSOperationQueuePriorityVeryLow = -8L,

NSOperationQueuePriorityLow = -4L,

NSOperationQueuePriorityNormal = 0,

NSOperationQueuePriorityHigh = 4,

NSOperationQueuePriorityVeryHigh = 8 

說明：優(yōu)先級高的任務，調用的幾率會更大。

（1）NSOperation之間可以設置依賴來保證執(zhí)行順序，?如一定要讓操作A執(zhí)行完后,才能執(zhí)行操作B,可以像下面這么寫

[operationB addDependency:operationA]; // 操作B依賴于操作

（2）可以在不同queue的NSOperation之間創(chuàng)建依賴關系 

注意：不能循環(huán)依賴（不能A依賴于B，B又依賴于A）。

（3）代碼示例

 1 #import "YYViewController.h" 2  3 @interface YYViewController () 4  5 @end 6  7 @implementation YYViewController 8  9 - (void)viewDidLoad10 {11     [super viewDidLoad];12 13     //創(chuàng)建NSInvocationOperation對象，封裝操作14     NSInvocationOperation *operation1=[[NSInvocationOperation alloc]initWithTarget:self selector:@selector(test1) object:nil];15     NSInvocationOperation *operation2=[[NSInvocationOperation alloc]initWithTarget:self selector:@selector(test2) object:nil];16     //創(chuàng)建對象，封裝操作17     NSBlockOperation *operation3=[NSBlockOperation blockOperationWithBlock:^{18         for (int i=0; i<5; i++) {19             NSLog(@"NSBlockOperation3--1----%@",[NSThread currentThread]);20         }21     }];22     [operation3 addExecutionBlock:^{23         for (int i=0; i<5; i++) {24         NSLog(@"NSBlockOperation3--2----%@",[NSThread currentThread]);25         }26     }];27     28     //設置操作依賴29     //先執(zhí)行operation2，再執(zhí)行operation1，最后執(zhí)行operation330     [operation3 addDependency:operation1];31     [operation1 addDependency:operation2];32     33     //不能是相互依賴34 //    [operation3 addDependency:operation1];35 //    [operation1 addDependency:operation3];36     37     //創(chuàng)建NSOperationQueue38     NSOperationQueue * queue=[[NSOperationQueue alloc]init];39     //把操作添加到隊列中40     [queue addOperation:operation1];41     [queue addOperation:operation2];42     [queue addOperation:operation3];43 }44 45 -(void)test146 {47     for (int i=0; i<5; i++) {48     NSLog(@"NSInvocationOperation--test1--%@",[NSThread currentThread]);49     }50 }51 52 -(void)test253 {54     for (int i=0; i<5; i++) {55     NSLog(@"NSInvocationOperation--test2--%@",[NSThread currentThread]);56     }57 }58 59 @end

 1 #import "YYViewController.h" 2  3 @interface YYViewController () 4  5 @end 6  7 @implementation YYViewController 8  9 - (void)viewDidLoad10 {11     [super viewDidLoad];12 13     //創(chuàng)建對象，封裝操作14     NSBlockOperation *operation=[NSBlockOperation blockOperationWithBlock:^{15         NSLog(@"-operation-下載圖片-%@",[NSThread currentThread]);16         //.....下載圖片后繼續(xù)進行的操作17         NSLog(@"--接著下載第二張圖片--");18     }];19     20     //創(chuàng)建隊列21     NSOperationQueue *queue=[[NSOperationQueue alloc]init];22     //把任務添加到隊列中（自動執(zhí)行，自動開線程）23     [queue addOperation:operation];24 }25 26 @end

 1 #import "YYViewController.h" 2  3 @interface YYViewController () 4  5 @end 6  7 @implementation YYViewController 8  9 - (void)viewDidLoad10 {11     [super viewDidLoad];12 13     //創(chuàng)建對象，封裝操作14     NSBlockOperation *operation=[NSBlockOperation blockOperationWithBlock:^{15         for (int i=0; i<10; i++) {16             NSLog(@"-operation-下載圖片-%@",[NSThread currentThread]);17         }18     }];19     20     //監(jiān)聽操作的執(zhí)行完畢21     operation.completionBlock=^{22         //.....下載圖片后繼續(xù)進行的操作23         NSLog(@"--接著下載第二張圖片--");24     };25     26     //創(chuàng)建隊列27     NSOperationQueue *queue=[[NSOperationQueue alloc]init];28     //把任務添加到隊列中（自動執(zhí)行，自動開線程）29     [queue addOperation:operation];30 }31 32 @end