iOS Development-Nsoperation advanced Features

Directly on the code

Example 1:

@interface Tbviewcontroller ()

Queue

@property (Nonatomic,strong) Nsoperationqueue *queue;

@end

Pause and resume of queue (drag two buttons in storyboard, pause, continue, connect, respectively)

Time out

-(ibaction) Pause

{

if (Self.queue.operationCount = = 0) {

NSLog (@ "no operation");

Return

}

Suspend pause is a queue, so the queue temporarily no longer dispatch tasks

NSLog (@ "pause");

[Self.queue Setsuspended:yes];

}

Go on

-(Ibaction) Resumue

{

if (Self.queue.operationCount = = 0) {

NSLog (@ "no operation");

Return

}

NSLog (@ "continue");

[Self.queue Setsuspended:no];

}

Lazy Loading

-(Nsoperationqueue *) queue

{

if (_queue = = nil) {

_queue = [[Nsoperationqueue alloc]init];

}

return _queue;

}

-(void) Touchesbegan: (Nsset *) touches withevent: (Uievent *) event

{

[Self opDemo1];

}

Simultaneous number of concurrent threads

-(void) OpDemo1

{

Thread-open queues are determined by the GCD, and programmers cannot participate in

/*

The benefit of setting the maximum number of concurrent threads: thread-on consumption

3g:2~3 threads, fewer threads, less traffic, saving money, saving power

Wifi:5~6 threads, many threads, high efficiency, large flow, no money, can be recharged at any time

*/

Self.queue Maxconcurrentoperationcount = 3;//Maximum concurrent quantity

for (int i = 0;i <; i + +) {

[Self.queue addoperationwithblock:^{

Blocking

[Nsthread Sleepfortimeinterval:2];

NSLog (@ "%@%d", [Nsthread CurrentThread];)

}];

}

}

Example 2: Operation Dependency-the order of execution of operations

-(void) OpDemo3

{

/*

For example:

1, download the small movie compression package

2. Decompression

3. Save the file

4. Notify the user

*/

NSBLOCKOPERATION*OP1 = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Download:%@", [Nsthread CurrentThread]);

}]；

NSBLOCKOPERATION*OP2 = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Decompression:%@", [Nsthread CurrentThread]);

}]；

NSBLOCKOPERATION*OP3 = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Save:%@", [Nsthread CurrentThread]);

}]；

NSBLOCKOPERATION*OP4 = [Nsblockoperation blockoperationwithblock:^{

NSLog (@ "Notify User:%@", [Nsthread CurrentThread]);

}]；

Depend on

[Op2 ADDDEPENDENCY:OP1];

[Op3 ADDDEPENDENCY:OP3];

[OP4 ADDDEPENDENCY:OP3];

Cyclic dependency (must not appear)

[Op1 ADDDEPENDENCY:OP4];

　　

Asynchronous waituntilfinished waits for all operations to complete before continuing

[Self.queue ADDOPERATIONS:@[OP1,OP2,OP3] waituntilfinished:no];

Primary queue

[[Nsoperationqueue Mainqueue] ADDOPERATION:OP4];

}

Summarize:

/*

Nsoperation

1. Is the package for the GCD

2, is OC, object-oriented, easy to use

3, provides some special methods, is GCD not easy to implement, for example: the maximum number of concurrent threads, pause and continue

4, you can specify the dependencies of the operation, the dependencies can be cross-queue

5, custom queue, is a concurrent queue, operation is an asynchronous task

GCD

1, is the C language, the difficulty is a bit big

2, once

3. After

4, GCD and a lot of complex functions

*/

iOS Development-Nsoperation advanced Features