我没有使用ARC。
通过Instruments测试泄漏时,当呈现UIAlertController时,会出现以下情况: 当我检查调用树时,它似乎在抱怨这个代码块。不确定其中多少是相关的,但无论如何,请看...
方法
最后,
通过Instruments测试泄漏时,当呈现UIAlertController时,会出现以下情况: 当我检查调用树时,它似乎在抱怨这个代码块。不确定其中多少是相关的,但无论如何,请看...
-(void) connection:(NSURLConnection*)connection didFailWithError:(NSError*)error {
// bunch of code
#ifndef NDEBUG
NSString* err_msg = [NSString stringWithFormat:@"%@%ld", @"Error number ", (long) error_code];
// @property (nonatomic, retain) id <DownloadMonitor> m_downloadMonitor;
[_m_downloadMonitor showDownloadAlert:err_msg withTitle:@"Download error"];
#endif
m_downloadMonitor
实际上是一个类型为 DashboardController 的对象,定义如下:
@interface DashboardController : BaseController <UIAlertViewDelegate, UITableViewDelegate, UITableViewDataSource, DownloadMonitor>
DownloadMonitor
是一个自定义协议,定义如下:
@protocol DownloadMonitor <NSObject>
-(void) downloadFinishedFor:(UIProgressView*)progress_bar;
-(void) downloadFailedFor:(UIProgressView*)progress_bar;
-(void) showDownloadAlert:(NSString*)message withTitle:(NSString*)title;
@end
方法
showDownloadAlert
在DashboardController
中定义如下:-(void) showDownloadAlert:(NSString*)message withTitle:(NSString*)title {
[self showPopupMessage:message withTitle:title andDelegate:self andActionHandlers:@{@"OK":@""}];
}
最后,
DashboardController
的父类 BaseController
中的 showPopupMessage
方法:- (void)showPopupMessage: (NSString*)message withTitle:(NSString*)title andDelegate:(BaseController*)delegate andActionHandlers:(NSDictionary*)handlers {
UIAlertController* alert = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
for ( id key in handlers ) {
NSString* button_name = (NSString*) key;
NSString* handler_name = (NSString*) [handlers objectForKey:key];
UIAlertAction* action;
if ( ! [handler_name isEqualToString:@""] ) {
SEL sel = NSSelectorFromString(handler_name);
action = [UIAlertAction actionWithTitle:button_name style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
[delegate performSelector:sel];
[alert dismissViewControllerAnimated:YES completion:NULL];
}];
}
else {
action = [UIAlertAction actionWithTitle:button_name style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
[alert dismissViewControllerAnimated:YES completion:NULL];
}];
}
[alert addAction:action];
}
[delegate presentViewController:alert animated:YES completion:nil];
}
为什么Instruments显示泄漏?
我看了这些线程:
iOS 8 Only Memory Leak with UIAlertController or UIActionSheet
UIAlertController memory leak/issues - Swift
它们似乎表明可能是一个错误......或者是我错过的保留周期。
UIAlertController* alert = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
- Ashalert
:[alert dismissViewControllerAnimated:YES completion:NULL];
是吗? - Ashdelegate
(我的第一个怀疑变量)和alert
弄混了。delegate
必须保持不变,但alert
必须用弱引用的__block
修饰符替换为blockAlert
。如果我的答案正确,请别忘了将其标记为正确/接受的答案。 - Nicolas Buquet