我正在尝试使用NSOperation
on在后台线程上实现搜索iOS
。我不想继承NSOperation
,所以这就是我正在做的事情:
[searchQueue cancelAllOperations];
NSInvocationOperation *op = [[NSInvocationOperation alloc] initWithTarget:self
elector:@selector(filterContentForSearchText:)
object:self.searchDisplayController.searchBar.text];
[searchQueue addOperation:op];
[op release];
search 方法包括一个 for 循环,用于检查正在搜索的内容是否在数组中。现在,当我NSOperation
通过调用取消时cancelAllOperations
,for 循环继续在数组中运行。我想防止这种情况发生,并想知道从 for 循环中调用它是否合法:
if ([[[searchQueue operations] objectAtIndex:0] isCancelled]) {
[tmp_array release]; // tmp_array is used to hold temporary results
[pool drain]; // pool is my autorelease pool
return;
}