初级多线程
-(NSString *)fetchSomethingFromServer
{
[NSThread sleepForTimeInterval:1];
return @"Hi there";
}
-(NSString *)processData:(NSString *)data
{
[NSThread sleepForTimeInterval:2];
return [data uppercaseString];
}
-(NSString *)calculateFirstResult:(NSString *)data
{
[NSThread sleepForTimeInterval:3];
return [NSString stringWithFormat:@"Number of chars:%d",[data length]];
}
-(NSString *)calculateSecondResult:(NSString *)data
{
[NSThread sleepForTimeInterval:4];
return [data stringByReplacingOccurrencesOfString:@"E" withString:@"e"];
}
-(void)doWork:(id)sender
{
NSDate *startTime=[NSDate date];
__block NSString *resultsSummary=@"a";
self.startButton.enabled=NO;
self.startButton.alpha=0.5;
[self.spinner startAnimating];
//设置分派组和队列
dispatch_queue_t queue=dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^{
NSString *fetchedData=[self fetchSomethingFromServer];
NSString *processedData=[self processData:fetchedData];
__block NSString *firstResult;
__block NSString *secondResult;
dispatch_group_t group=dispatch_group_create();
dispatch_group_async(group, queue, ^{
firstResult=[self calculateFirstResult:processedData];
});
dispatch_group_async(group, queue, ^{
secondResult=[self calculateSecondResult:processedData];
});
dispatch_group_notify(group, queue, ^{
resultsSummary=[NSString stringWithFormat:@"First:[%@]\nSecond:[%@]",firstResult,secondResult];
NSLog(@"继续运行-->%@",resultsSummary);
});
// NSString *firstResult=[self calculateFirstResult:processedData];
// NSString *secondResult=[self calculateSecondResult:processedData];
// NSString *resultsSummary=[NSString stringWithFormat:@"First:[%@]\nSecond:[%@]",firstResult,secondResult];
dispatch_async(dispatch_get_main_queue(), ^{
self.resultsTextView.text=resultsSummary;
NSLog(@"继续运行-->%@",resultsSummary);
self.startButton.enabled=YES;
self.startButton.alpha=1.0;
[self.spinner stopAnimating];
});
NSDate *endTime=[NSDate date];
NSLog(@"Completed in %f seconds",[endTime timeIntervalSinceDate:startTime]);
});
}