NSOPeration NSOperationQueue

2019-11-09 18:52:05

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NSOperation是一个抽象类。实际开发中用它的两个子类：NSInvocationOperation NSBlockOperation

//NSBlockOperation可以通过block异步执行任务，且block里面的代码是同步的- (void)blockOperationTest{ NSBlockOperation *blockOperation = [NSBlockOperation blockOperationWithBlock:^{ NSLog(@"1在第%@个线程",[NSThread currentThread]); NSLog(@"1haha"); }]; [blockOperation addExecutionBlock:^{ NSLog(@"2在第%@个线程",[NSThread currentThread]); NSLog(@"2haha"); }]; [blockOperation addExecutionBlock:^{ NSLog(@"3在第%@个线程",[NSThread currentThread]); NSLog(@"3haha"); }]; [blockOperation addExecutionBlock:^{ NSLog(@"4在第%@个线程",[NSThread currentThread]); NSLog(@"4haha"); }]; [blockOperation addExecutionBlock:^{ NSLog(@"5在第%@个线程",[NSThread currentThread]); NSLog(@"5haha"); }]; [blockOperation addExecutionBlock:^{ NSLog(@"6在第%@个线程",[NSThread currentThread]); NSLog(@"6haha"); }];// [blockOperation start]; NSOperationQueue *queue = [[NSOperationQueue alloc] init]; [queue addOperation:blockOperation];}//不放大queue里面在主线程同步执行

NSInvocationOperation 类似于button添加点击事件

- (void)invocationTest{ NSInvocationOperation *invo = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(testNSOperation) object:nil]; NSOperationQueue *queue = [[NSOperationQueue alloc] init]; [queue addOperation:invo]; //不放大queue里面在主线程同步执行}

添加依赖关系是Queue的最大特征

- (void)relationTest{ NSInvocationOperation *op1 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(testWithOperation1) object:nil]; op1.completionBlock = ^(){ }; NSInvocationOperation *op2 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(testWithOperation2) object:nil]; op2.completionBlock = ^(){ }; NSInvocationOperation *op3 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(testWithOperation3) object:nil]; NSInvocationOperation *op4 = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(testWithOperation4) object:nil]; NSOperationQueue *queue = [[NSOperationQueue alloc] init]; [op2 addDependency:op1]; // 操作2依赖于操作1 [op3 addDependency:op2]; [op4 addDependency:op3]; [queue addOperation:op4]; [queue addOperation:op3]; [queue addOperation:op2]; [queue addOperation:op1];}

ios 针对http请求失效：https://segmentfault.com/a/1190000002933776 继承NSOperation 的图片请求operation类，只需要重新写main 方法

#import <Foundation/Foundation.h>#import <UIKit/UIKit.h>@PRotocol SDDownloadOperationDelegate <NSObject>- (void)downloadFinishWithImage:(UIImage *)image;@end@interface SDDownloadOperation : NSOperation@property (nonatomic, copy) NSString *imageURL;@property (nonatomic, weak) id <SDDownloadOperationDelegate> delegate;- (instancetype)initWithUrl:(NSString *)url delegate:(id<SDDownloadOperationDelegate>)delegate;@end#import "SDDownloadOperation.h"@implementation SDDownloadOperation- (instancetype)initWithUrl:(NSString *)url delegate:(id<SDDownloadOperationDelegate>)delegate{ self = [super init]; if (!self) { return nil; } self.imageURL = url; self.delegate = delegate; return self;}- (void)main{ if (self.isCancelled) { return; } NSURL *url = [NSURL URLWithString:self.imageURL]; NSData *imageData = [NSData dataWithContentsOfURL:url]; if (self.isCancelled) { url = nil; imageData = nil; return; } UIImage *image = [UIImage imageWithData:imageData]; if (self.isCancelled) { imageData = nil; return; } if (self.delegate && [self.delegate respondsToSelector:@selector(downloadFinishWithImage:)]) { [self.delegate downloadFinishWithImage:image]; }}@end

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