iOS处理耗时操作一种简单方法

在开发过程中，我们经常会遇到一下耗时的操作，比如说文件的上传、下载、压缩、解压缩等过程，开发过蓝牙的小伙伴都知道蓝牙的操作也是一个耗时的操作，尤其是那些以蓝牙为工具的项目，比如说蓝牙在智能家居中的使用，这些都是耗时的操作。有时候我们需要对这些耗时的操作精准的加以控制，这时候大多数人都会想到用多线程来处理，那么怎样才能用相对简单的代码来实现对这些耗时操作的控制呢？

在OC中有很多方法都能实现，这里我只说我经常用的NSOperation和NSOperationQueue相结合的方法

这里是通过NSOperation的子类，通过相关代码来控制它的状态（如果对NSOperation的四种状态不了解的童鞋可以自行补脑，这里就不多说了）来实现，下面是声明文件内容：

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#import "HJBlockOperation.h"
#import <Foundation/Foundation.h>@class HJBlockOperation;typedef void (^continueBlock)(HJBlockOperation *con);@interface HJBlockOperation : NSOperation//仿NSOperation的四种状态 写出自己可以控制的对应的状态属性（ready状态暂时用不到，就不写了，其实最主要的就一个：isFinished，只有这个状态变成YES，才证明这个操作完成了）@property(nonatomic ,assign , getter = isFinished)BOOL hjFinished;@property(nonatomic ,assign , getter = isExecuting)BOOL hjExecuting;@property(nonatomic ,assign , getter = isConcurrent)BOOL hjConcurrent;@property(nonatomic, copy) continueBlock myBlock;- (void)continueWithBlock:(continueBlock)blk;@end

实现方法也是很简单，只需要这写代码

#import "HJBlockOperation.h"@implementation HJBlockOperation-(void)main{    @autoreleasepool {                if (self.isCancelled) {            return;        }                _hjConcurrent =YES;        [[NSOperationQueue mainQueue] addOperationWithBlock:^{            self.myBlock(self);        }];            }}-(void)continueWithBlock:(continueBlock)blk{    if (blk) {        self.myBlock = blk;    }}- (void)setHjFinished:(BOOL)hjFinished{    [self willChangeValueForKey:@"isFinished"];    _hjFinished = hjFinished;    [self didChangeValueForKey:@"isFinished"];}- (void)setHjExecuting:(BOOL)hjExecuting{    [self willChangeValueForKey:@"isExecuting"];    _hjExecuting = hjExecuting;    [self didChangeValueForKey:@"isExecuting"];}- (void)setHjConcurrent:(BOOL)hjConcurrent{    _hjConcurrent = hjConcurrent;}@end

调用时候是这样的：

NSOperationQueue *queue = [[NSOperationQueue alloc] init];    queue.maxConcurrentOperationCount = 1;        NSMutableArray *operaArray = [NSMutableArray array];    for (int index = 0; index < 1; index ++) {                HJBlockOperation *blo = [[HJBlockOperation alloc] init];                [blo continueWithBlock:^(HJBlockOperation *con) {                        NSLog(@"第%d条任务开始",index + 1);                        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{                                NSLog(@"第%d条任务结束",index + 1);                                //等任务结束后调用这句代码，就标明此操作已结束                blo.hjFinished = YES;            });                    }];                [operaArray addObject:blo];    }            HJBlockOperation *operation = [[HJBlockOperation alloc] init];        [operation continueWithBlock:^(HJBlockOperation *con) {                NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://ppt.downhot.com/d/file/p/2014/08/16/0b999aee4d45bc266637043b7cf04654.jpg"]];        NSLog(@"开始下载图片");        if (data) {            operation.hjFinished = YES;                        NSLog(@"下载完了");                        dispatch_async(dispatch_get_main_queue(), ^{                                _imageView.image = [UIImage imageWithData:data];                            });        }    }];    [operaArray addObject:operation];        [queue addOperations:operaArray waitUntilFinished:NO];

源代码：https://github.com/HJZone/HJBlockOperation