我有一个 UIViewController。我使用 navigationItem 的 rightBarButtonItem 作为“重新加载按钮”。当按下重新加载按钮时,我使用 leftBarButtonItem 在应用程序处理要重新加载的数据时显示活动指示器。到这里为止一切都很好。
这是一些代码:
- (void)initSpinner {
activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
activityButton = [[UIBarButtonItem alloc] initWithCustomView: activityIndicator];
self.navigationItem.leftBarButtonItem = activityButton;
}
- (void)spinBegin {
[activityIndicator startAnimating];
}
- (void)spinEnd {
[activityIndicator stopAnimating];
}
- (void)viewDidLoad {
[self initSpinner];
[super viewDidLoad];
//more stuff going on here....
}
-(void) loadView{
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refreshFeeds:)];
}
现在我被要求稍微改变逻辑。
rightBarButtonItem 保持原样。leftBarButtonItem 仍然在那里显示活动指示器,但是当没有处理时,它应该显示另一个按钮,当按下时将显示一个新视图(用于某些信息)。
所以我做了这些改变:
- (void)initSpinner {
activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
activityButton = [[UIBarButtonItem alloc] initWithCustomView: activityIndicator];
}
- (void)spinBegin {
self.navigationItem.leftBarButtonItem = activityButton;
[activityIndicator startAnimating];
}
- (void)spinEnd {
[activityIndicator stopAnimating];
self.navigationItem.leftBarButtonItem =infoBarButton; //= [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refreshFeeds:)] autorelease];
}
-(void) loadView{
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(refreshFeeds:)];
if (infoBarButton == nil){
UIImage *buttonImage = [UIImage imageNamed:@"info.png"];
UIButton *aButton = [UIButton buttonWithType:UIButtonTypeCustom];
[aButton setImage:buttonImage forState:UIControlStateNormal];
aButton.frame = CGRectMake(0.0, 0.0, 25, 25);
// Initialize the UIBarButtonItem
infoBarButton = [[UIBarButtonItem alloc] initWithCustomView:aButton];
// Set the Target and Action for aButton
[aButton addTarget:self action:@selector(showInfo:) forControlEvents:UIControlEventTouchUpInside];
}
self.navigationItem.leftBarButtonItem = infoBarButton;
}
虽然它似乎正在工作(信息按钮在那里,当我按下“重新加载”时,activityIndicator 会占据它的位置,直到处理完成),我在调试器控制台中得到以下信息:
__NSAutoreleaseNoPool(): Object 0x15ef30 of class UINavigationItem autoreleased with no pool in place - just leaking
__NSAutoreleaseNoPool(): Object 0x1abd90 of class UIBarButtonItem autoreleased with no pool in place - just leaking
__NSAutoreleaseNoPool(): Object 0x1acb20 of class UIButton autoreleased with no pool in place - just leaking
__NSAutoreleaseNoPool(): Object 0x15ef30 of class UINavigationItem autoreleased with no pool in place - just leaking
__NSAutoreleaseNoPool(): Object 0x1ad030 of class UIActivityIndicatorView autoreleased with no pool in place - just leaking
__NSAutoreleaseNoPool(): Object 0x1ad030 of class UIActivityIndicatorView autoreleased with no pool in place - just leaking
__NSAutoreleaseNoPool(): Object 0x1a8c40 of class UINavigationButton autoreleased with no pool in place - just leaking
Object 0x941c of class NSCFString autoreleased with no pool in place - just leaking
//MORE similar messages following...
我究竟做错了什么?我希望有人可以提供帮助...
在此先感谢。