我试图使 -[NSString stringWithContentsOfURL:encoding:error:] 异步,通过从后台线程异步运行它:
__block NSString *result;
dispatch_queue_t currentQueue = dispatch_get_current_queue();
void (^doneBlock)(void) = ^{
printf("done! %s",[result UTF8String]);
};
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,
(unsigned long)NULL), ^(void) {
result = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com/"] encoding:NSUTF8StringEncoding error:nil];
dispatch_sync(currentQueue, ^{
doneBlock();
});
});
它工作正常,最重要的是,它是异步的。
我的问题是这样做是否安全,或者是否存在任何线程问题等?
提前致谢 :)