<强> IOS多线程编程NSThread的使用方法
NSThread是多线程的一种,有两种方法创建子线程
(1)优点:NSThread比肾小球囊性肾病,NSOperation都轻量级
(2)缺点:需要自己管理线程的生命周期,线程同步。线程同步对数据的加锁会有一定的系统开销
第一种是隐藏创建,有以下几种方式:
(1)多用于串行:- (id) performSelector: (SEL) aSelector withObject: (id)对象;
(2)后台执行,多用于并行:- (void) performSelectorInBackground: (SEL) aSelector withObject: arg (nullable id),
(3)延迟执行:- (void) performSelector: (SEL) aSelector withObject:(可空id)条件下afterDelay: (NSTimeInterval)延迟;
(4)回到主线程执行:- (void) performSelectorOnMainThread: (SEL) aSelector withObject:(可空id) arg waitUntilDone: (BOOL)等;
注意:
(1)通过方法”+ (void) cancelPreviousPerformRequestsWithTarget: (id) aTarget选择器:(SEL) aSelector对象:(可空id)条件下,,”,或“+ (void) cancelPreviousPerformRequestsWithTarget: (id) aTarget“停止执行;,
示例:
//创建子线程-隐式方法
//子线程——串行
【自我performSelector: @ selector (showCount:) withObject: @ (11)];
【自我performSelector: @ selector (showCount:) withObject: @ (12)];
【自我performSelector: @ selector (showCount:) withObject: @ (23)];
//子线程——并行(后台),
【自我performSelectorInBackground: @ selector (showCount:) withObject: @ (41)];
【自我performSelectorInBackground: @ selector (showCount:) withObject: @ (42)];
之前
//回到主线程
【自我performSelectorOnMainThread: @ selector (showCount:) withObject: @ (51) waitUntilDone:是的);
//子线程延迟执行
【自我performSelector: @ selector (showCount:) withObject: @ (61) afterDelay: 5.0);
之前
//停止
(NSObject cancelPreviousPerformRequestsWithTarget:自我);之前
,第二种是显示创建,方式如下:
- (instancetype) initWithTarget: (id)目标选择器:(SEL)选择器对象:(可空id)参数;
之前
注意:
,(1)通过方法”- (void)开始;“开始执行;
,(2)通过方法”- (void)取消;“停止执行;,,
,示例:
,//创建子线程——显示方法
自我。线程=[[NSThread alloc] initWithTarget:自我选择器:@ selector (showCount:)对象:@ (61);
self.thread.name=@”计数”;
(自我。线程开始);
(自我。线程取消);
之前
代码示例
- (void) showCount: (NSNumber *)号码
{
NSInteger数=arc4random () % 1000;
数=1000;
for (int i=0;我& lt;计数;我+ +)
{
NSLog(@“第% @个i=% @”,数字,@(我));//休眠n秒再执行
[NSThread sleepForTimeInterval: 0.2);//停止//BOOL isStop=[自我。线程isCancelled];//如果(isStop)//{//NSLog(@“2停止”);//中断;//}
如果(isCancelThread)
{
NSLog(@“2停止”);
打破;
}
}
}
之前
bool isCancelThread=没有;
- (void) stopClick
{
(NSObject cancelPreviousPerformRequestsWithTarget:自我);
如果(self.thread)
{
BOOL isExecuting=[自我。线程isExecuting];
如果(isExecuting)
{
NSLog(@“1停止”);//(自我。线程取消);
isCancelThread=是的;
}
}
}
之前
- (void) downloadImage: imageUrl (NSString *)
{
NSURL * url=[NSURL URLWithString imageUrl):;
NSData *数据=[[NSData alloc]并:url];
用户界面图像*图像=[[界面图像alloc] initWithData:数据);
如果(图片==nil)
{
}
其他的
{
(自我performSelectorOnMainThread://@ selector (updateImage:) withObject:图像waitUntilDone:是的);
【自我performSelectorInBackground: @ selector (updateImage:) withObject:图像);
}//NSURL * url=[NSURL URLWithString imageUrl):;//NSURLRequest *请求=[NSURLRequest requestWithURL: url];//NSURLSession *会话=[NSURLSession sharedSession);//NSURLSessionDataTask * dataTask=[会话dataTaskWithRequest:请求completionHandler: ^ (NSData *数据,NSURLResponse *反应,NSError *误差){//////输出返回的状态码,请求成功的话为200//NSHTTPURLResponse * httpResponse=(NSHTTPURLResponse *)反应;//NSInteger responseStatusCode=[httpResponse statusCode];//NSLog (@“% ld”, responseStatusCode);////用户界面图像*图像=[界面图像imageWithData:数据);////(自我performSelectorOnMainThread: @ selector (updateImage:) withObject:图像waitUntilDone:是的);
(自我performSelectorInBackground://@ selector (updateImage:) withObject:图像);//});//////使用的简历方法启动任务//(dataTask简历);
}
