iphone - Exc_Bad_Access 有时仅在显示警报 View 时

Question

我有很多线程通过 performSeleactoreOnMainThread 方法调用以下函数:

-(void) showAlert: (NSString *)message{
if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
    NSLog(@"<< perform in main thread>>");
    [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
}
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}

因为，在任何情况下，这个方法只会在主线程上调用，我没有得到 EXC_BAD_ACCESS 崩溃的原因: [警报显示]

而且这种崩溃只是偶尔发生。请帮忙。

Answer 1

我猜你忘了在你的代码中添加 return; 这样你的 if 下面的代码也会被执行，无论它是否在主循环中。

一个简单的修复可能是:

-(void) showAlert: (NSString *)message{
    if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
        NSLog(@"<< perform in main thread>>");
        [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
        return;
    }
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alert show];
}