dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
／／首先判断当前栈是否大于0
if (!((int)self.navigationController.viewControllers.count > 0 )) {
dispatch_async(dispatch_get_main_queue(), ^{
／／销毁强引用量
});
}else{
for (int i = (int)self.navigationController.viewControllers.count - 1 ; i >= 0; i--) {
if ([self.navigationController.viewControllers objectAtIndex:i] == self) {
break;
}
if(i == 0 ){
dispatch_async(dispatch_get_main_queue(), ^{
／／销毁强引用量
});
}
}
}
});