delegates

问题 I'm having trouble with mutli threading programming in my application. Actually, the code looks something like this: Private Delegate Sub IniciarDiscagemDelegate() Private Sub CallBack() 'do some stuff.... ThreadDiscagem = New Threading.Thread(AddressOf IniciarDiscagem) ThreadDiscagem.IsBackground = True ThreadDiscagem.Start() End Sub Private Sub IniciarDiscagem() If Me.InvokeRequired() Then Me.BeginInvoke(New IniciarDiscagemDelegate(AddressOf IniciarDiscagem)) Exit Sub End If Do While True

问题 I'm having trouble with mutli threading programming in my application. Actually, the code looks something like this: Private Delegate Sub IniciarDiscagemDelegate() Private Sub CallBack() 'do some stuff.... ThreadDiscagem = New Threading.Thread(AddressOf IniciarDiscagem) ThreadDiscagem.IsBackground = True ThreadDiscagem.Start() End Sub Private Sub IniciarDiscagem() If Me.InvokeRequired() Then Me.BeginInvoke(New IniciarDiscagemDelegate(AddressOf IniciarDiscagem)) Exit Sub End If Do While True

问题 Suppose , We have 3 ViewControllers called ViewControllerA , ViewControllerB , ViewControllerC in our UINavigationController . To be specific , ViewControllerA is the RootViewController and ViewControllerB and ViewControllerC are pushed on it. So, Currently ViewControllerC is on the Top and visible to user. I want to return to ViewControllerA by calling [self.navigationController popToRootViewControllerAnimated:YES]; method and pass some data to ViewControllerA from here. I have to update

问题 I'm probably doing something silly, but here it goes. I'm trying to get the FieldInfo from a public event via reflection. Check this function: public void PlotAllFields(Type type) { BindingFlags all = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public; FieldInfo[] fields = type.GetFields(all); Console.WriteLine(type + "-------------------------"); foreach (var fieldInfo in fields) { Console.WriteLine(fieldInfo.Name); } } public class Bar : Foo {} public class Foo { public

问题 I have a ViewController that is set as delegate of MKMapView and CLLocationManager . This ViewController also receives actions from UI buttons. I have a state machine that needs to be updated whenever some UI action happens or when a new location is available (whether it comes from MKMapView or CLLocationManager ) Obviously, the state machine update must be atomic, but I can't seem to find a good mechanism to do so. Here's a snippet of the code: m_locationSerialQueue = dispatch_queue_create(

问题 I'm having trouble changing the index of my UITabBar. I am attempting to change it from the UITabBarController subclass. This is what I'm trying: [self.tabBarController setSelectedIndex:1]; This is what my .h looks like #import <UIKit/UIKit.h> @interface CustomTab : UITabBarController <UITabBarControllerDelegate>{ IBOutlet CustomTab *bar; } @end I am trying to set the index with an IBAction, the method is being called, but the index doesn't change. Any ideas? 回答1: Because you are calling

问题 I have a custom view (settingview) with nib and protocol. i want to add this view on a viewcontoller with delegate. When i set its delegate my app crashes and i don't know what i have done wrong. i don't have NIB for ViewController. i am attaching few images of my code and View's NIB. .h @protocol SettingViewDelegate @required -(void)CornerSlider:(id)sender; -(void)MarginSlider:(id)sender; -(void)BorderSlider:(id)sender; -(void)ShadowSlider:(id)sender; -(void)BorderColor:(id)sender; -(void

问题 I noticed that when I do this : [myParser setDelegate:self]; it works :D (even if I didn't add the code in the header file ... you know, the <delegateStuff, delegateOtherStuff> in the interface declaration) When are you supposed to modify the header file to make your delegate work ? Is the setDelegate method enough to make it work ? Cheers for any help ;) Gauthier 回答1: In short, the <NSXMLParserDelegate> in your interface declaration is not required, it's there for error checking at compile

问题 Im using AudioServicesPlaySystemSound(soundID); to play a sound, but I need to know when the sound has stopped playing, so what is the delegate for this? Thanks! 回答1: Have you read the documentation? AudioServicesPlaySystemSound Plays a system sound object. void AudioServicesPlaySystemSound ( SystemSoundID inSystemSoundID ); Discussion This function plays a short sound (30 seconds or less in duration). Because sound might play for several seconds, this function is executed asynchronously. To

问题 I am making an OpenSource (github) helper class for downloading images asynchronously (I had major trouble with). However, I have delegate methods set up to alert the delegate that a image has finished downloading. The problem is that the delegate method is not getting called. I am setting the delegate and everything, but I don't have a clue why the problem is occurring. Please take a look at my code! I have only posted the relevant code. MKAsyncImageDownloader.h @protocol