ios开发多线程二：NSOperationQueue的基本使用

#import "ViewController.h"
#import "XMGOperation.h"

@interface ViewController ()

@end

@implementation ViewController

#pragma mark ----------------------
#pragma mark Events
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [self customWithQueue];
}

#pragma mark ----------------------
#pragma mark Methods

-(void)invocationOperationWithQueue
{
    //1.创建操作,封装任务
    /*
     第一个参数:目标对象 self
     第二个参数:调用方法的名称
     第三个参数:前面方法需要接受的参数 nil
     */
    NSInvocationOperation *op1 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(download1) object:nil];
    NSInvocationOperation *op2 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(download2) object:nil];
    NSInvocationOperation *op3 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(download3) object:nil];

    //2.创建队列
    /*
     GCD:
     串行类型:create & 主队列
     并发类型:create & 全局并发队列
     NSOperation:1：本身不能进行封装任务，必须依靠其子类，NSInvocationOperation，NSBlockOperation或是自定义类，重写main方法来封装任务。这三个子类若没有指定队列，则默认任务是在当前队列中执行的
     主队列:   [NSOperationQueue mainQueue] 和GCD中的主队列一样,串行队列
     非主队列: [[NSOperationQueue alloc]init]  非常特殊(同时具备并发和串行的功能)
     //默认情况下,非主队列是并发队列：可通过设置最大并发数：为0：没有队列执行操作，1：主队列 大于1，并发队列     */
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];

    //3.添加操作到队列中
    [queue addOperation:op1];   //内部已经调用了[op1 start]
    [queue addOperation:op2];
    [queue addOperation:op3];
}

-(void)blockOperationWithQueue
{
    //1.创建操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1----%@",[NSThread currentThread]);

    }];

    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"2----%@",[NSThread currentThread]);
    }];

    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"3----%@",[NSThread currentThread]);
    }];

    //追加任务：当某个操作的任务数量大于1时，默认会开启子线程并发执行，有可能是子线程有可能是主线程不确定
    [op2 addExecutionBlock:^{
        NSLog(@"4----%@",[NSThread currentThread]);
    }];

    [op2 addExecutionBlock:^{
        NSLog(@"5----%@",[NSThread currentThread]);
    }];

    [op2 addExecutionBlock:^{
        NSLog(@"6----%@",[NSThread currentThread]);
    }];

    //2.创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];

    //3.添加操作到队列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue addOperation:op3];

    //简便方法：addOperationWithBlock：直接封装任务添加到队列中
    //1)创建操作,2)添加操作到队列中
    [queue addOperationWithBlock:^{
        NSLog(@"7----%@",[NSThread currentThread]);
    }];

}

-(void)customWithQueue
{
    //1.封装操作
    XMGOperation *op1 = [[XMGOperation alloc]init];
    XMGOperation *op2 = [[XMGOperation alloc]init];

    //2.创建队列
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];

    //3.添加操作到队列
    [queue addOperation:op1];
    [queue addOperation:op2];

}

-(void)download1
{
    NSLog(@"%s----%@",__func__,[NSThread currentThread]);
}

-(void)download2
{
    NSLog(@"%s----%@",__func__,[NSThread currentThread]);
}

-(void)download3
{
    NSLog(@"%s----%@",__func__,[NSThread currentThread]);
}

@end

#import "XMGOperation.h"

@implementation XMGOperation

//告知要执行的任务是什么
//1.有利于代码隐蔽
//2.复用性
-(void)main
{
    NSLog(@"main---%@",[NSThread currentThread]);
}
@end

#import "ViewController.h"
#import "XMGOperation.h"

@interface ViewController ()
/** 队列 */
@property (nonatomic, strong) NSOperationQueue *queue;
@end

@implementation ViewController

#pragma mark ----------------------
#pragma mark Events

/**
 * 1:先创建队列，设置最大并发数，来决定是串行还是并发，三种方式封装任务，将任务添加到队列（也可以快速实现封装任务到队列）2：任务的取消暂停
 *
 */
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [self test2];
}

- (IBAction)startBtnClick:(id)sender
{
    //1.创建队列
    //默认是并发队列
    self.queue = [[NSOperationQueue alloc]init];

    //2.设置最大并发数量 maxConcurrentOperationCount
    self.queue.maxConcurrentOperationCount = ;

    XMGOperation *op1 = [[XMGOperation alloc]init];

    //4.添加到队列
    [self.queue addOperation:op1];
}

- (IBAction)suspendBtnClick:(id)sender
{
    //暂停,是可以恢复
    /*
     队列中的任务也是有状态的:已经执行完毕的 | 正在执行 | 排队等待状态
     */
    //不能暂停当前正在处于执行状态的任务
    [self.queue setSuspended:YES];
}

- (IBAction)goOnBtnClick:(id)sender
{
    //继续执行
    [self.queue setSuspended:NO];
}

- (IBAction)cancelBtnClick:(id)sender
{
    //取消,不可以恢复
    //该方法内部调用了所有操作的cancel方法
    [self.queue cancelAllOperations];
}

-(void)test
{
    //1.创建队列
    //默认是并发队列
    NSOperationQueue *queue = [[NSOperationQueue alloc]init];

    //2.设置最大并发数量 maxConcurrentOperationCount
    //同一时间最多有多少个任务可以执行
    //串行执行任务!=只开一条线程 (线程同步)
    // maxConcurrentOperationCount >1 那么就是并发队列
    // maxConcurrentOperationCount == 1 那就是串行队列
    // maxConcurrentOperationCount == 0  不会执行任务
    // maxConcurrentOperationCount == -1 特殊意义 最大值 表示不受限制
    queue.maxConcurrentOperationCount = ;

    //3.封装操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"1----%@",[NSThread currentThread]);
    }];

    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"2----%@",[NSThread currentThread]);
    }];

    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"3----%@",[NSThread currentThread]);
    }];

    NSBlockOperation *op4 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"4----%@",[NSThread currentThread]);
    }];

    NSBlockOperation *op5 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"5----%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op6 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"6----%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op7 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"7----%@",[NSThread currentThread]);
    }];

    //4.添加到队列
    [queue addOperation:op1];
    [queue addOperation:op2];
    [queue addOperation:op3];
    [queue addOperation:op4];
    [queue addOperation:op5];
    [queue addOperation:op6];
    [queue addOperation:op7];
}

-(void)test2
{
    //1.创建队列
    //默认是并发队列
    self.queue = [[NSOperationQueue alloc]init];

    //2.设置最大并发数量 maxConcurrentOperationCount
    //同一时间最多有多少个任务可以执行
    //串行执行任务!=只开一条线程 (线程同步)
    // maxConcurrentOperationCount >1 那么就是并发队列
    // maxConcurrentOperationCount == 1 那就是串行队列
    // maxConcurrentOperationCount == 0  不会执行任务
    // maxConcurrentOperationCount == -1 特殊意义 最大值 表示不受限制
    self.queue.maxConcurrentOperationCount = ;

    //3.封装操作
    NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{
        for (NSInteger i = ; i<; i++) {
            NSLog(@"1-%zd---%@",i,[NSThread currentThread]);
        }
    }];

    NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{
        for (NSInteger i = ; i<; i++) {
            NSLog(@"2-%zd---%@",i,[NSThread currentThread]);
        }
    }];

    NSBlockOperation *op3 = [NSBlockOperation blockOperationWithBlock:^{
        for (NSInteger i = ; i<; i++) {
            NSLog(@"3-%zd---%@",i,[NSThread currentThread]);
        }
    }];

    NSBlockOperation *op4 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"4----%@",[NSThread currentThread]);
    }];

    NSBlockOperation *op5 = [NSBlockOperation blockOperationWithBlock:^{
        for (NSInteger i = ; i<; i++) {
            NSLog(@"5-%zd---%@",i,[NSThread currentThread]);
        }
    }];
    NSBlockOperation *op6 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"6----%@",[NSThread currentThread]);
    }];
    NSBlockOperation *op7 = [NSBlockOperation blockOperationWithBlock:^{
        NSLog(@"7----%@",[NSThread currentThread]);
    }];

    //4.添加到队列
    [self.queue addOperation:op1];
    [self.queue addOperation:op2];
    [self.queue addOperation:op3];
    [self.queue addOperation:op4];
    [self.queue addOperation:op5];
    [self.queue addOperation:op6];
    [self.queue addOperation:op7];
}

-(void)demo
{
}

@end

- 2.2 NSOperationQueue基本使用

（1）NSOperation中的两种队列

01 主队列 通过mainQueue获得，凡是放到主队列中的任务都将在主线程执行

02 非主队列 直接alloc init出来的队列。非主队列同时具备了并发和串行的功能，通过设置最大并发数属性来控制任务是并发执行还是串行执行

（2）相关代码

```objc

//自定义NSOperation

-(void)customOperation

{

//1.创建队列

NSOperationQueue *queue = [[NSOperationQueue alloc]init];

//2.封装操作

//好处：1.信息隐蔽

//2.代码复用

XMGOperation *op1 = [[XMGOperation alloc]init];

XMGOperation *op2 = [[XMGOperation alloc]init];

//3.添加操作到队列中

[queue addOperation:op1];

[queue addOperation:op2];

}

//NSBlockOperation

- (void)block

{

//1.创建队列

NSOperationQueue *queue = [[NSOperationQueue alloc]init];

//2.封装操作

NSBlockOperation *op1 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"1----%@",[NSThread currentThread]);

}];

NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:^{

NSLog(@"2----%@",[NSThread currentThread]);

}];

[op2 addExecutionBlock:^{

NSLog(@"3----%@",[NSThread currentThread]);

}];

[op2 addExecutionBlock:^{

NSLog(@"4----%@",[NSThread currentThread]);

}];

//3.添加操作到队列中

[queue addOperation:op1];

[queue addOperation:op2];

//补充：简便方法

[queue addOperationWithBlock:^{

NSLog(@"5----%@",[NSThread currentThread]);

}];

}

//NSInvocationOperation

- (void)invocation

{

/*

GCD中的队列：

串行队列：自己创建的，主队列

并发队列：自己创建的，全局并发队列

NSOperationQueue

主队列：[NSOperationQueue mainqueue];凡事放在主队列中的操作都在主线程中执行

非主队列：[[NSOperationQueue alloc]init]，并发和串行，默认是并发执行的

*/

//1.创建队列

NSOperationQueue *queue = [[NSOperationQueue alloc]init];

//2.封装操作

NSInvocationOperation *op1 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(download1) object:nil];

NSInvocationOperation *op2 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(download2) object:nil];

NSInvocationOperation *op3 = [[NSInvocationOperation alloc]initWithTarget:self selector:@selector(download3) object:nil];

//3.把封装好的操作添加到队列中

[queue addOperation:op1];//[op1 start]

[queue addOperation:op2];

[queue addOperation:op3];

}

```

- 2.3 NSOperation其它用法

（1）设置最大并发数【控制任务并发和串行】

```objc

//1.创建队列

NSOperationQueue *queue = [[NSOperationQueue alloc]init];

//2.设置最大并发数

//注意点：该属性需要在任务添加到队列中之前进行设置

//该属性控制队列是串行执行还是并发执行

//如果最大并发数等于1，那么该队列是串行的，如果大于1那么是并行的

//系统的最大并发数有个默认的值，为-1，如果该属性设置为0，那么不会执行任何任务

queue.maxConcurrentOperationCount = 2;

```

（2）暂停和恢复以及取消

```objc

//设置暂停和恢复

//suspended设置为YES表示暂停，suspended设置为NO表示恢复

//暂停表示不继续执行队列中的下一个任务，暂停操作是可以恢复的

if (self.queue.isSuspended) {

self.queue.suspended = NO;

}else

{

self.queue.suspended = YES;

}

//取消队列里面的所有操作

//取消之后，当前正在执行的操作的下一个操作将不再执行，而且永远都不在执行，就像后面的所有任务都从队列里面移除了一样

//取消操作是不可以恢复的

[self.queue cancelAllOperations];

---------自定义NSOperation取消操作--------------------------

-(void)main

{

//耗时操作1

for (int i = 0; i<1000; i++) {

NSLog(@"任务1-%d--%@",i,[NSThread currentThread]);

}

NSLog(@"+++++++++++++++++++++++++++++++++");

//苹果官方建议，每当执行完一次耗时操作之后，就查看一下当前队列是否为取消状态，如果是，那么就直接退出

//好处是可以提高程序的性能

if (self.isCancelled) {

return;

}

//耗时操作2

for (int i = 0; i<1000; i++) {

NSLog(@"任务1-%d--%@",i,[NSThread currentThread]);

}

NSLog(@"+++++++++++++++++++++++++++++++++");

}

```