2014/10/15 下午 10:12:16

iphone Programming Glossary: observe

Get notification when NSOperationQueue finishes all tasks

http://stackoverflow.com/questions/1049001/get-notification-when-nsoperationqueue-finishes-all-tasks

is received. iphone asynchronous queue notifications nsoperation share improve this question Use KVO to observe the operations property of your queue then you can tell if your queue has completed by checking for queue.operations count.. your queue do this self.queue addObserver self forKeyPath @ operations options 0 context NULL Then do this in your observeValueForKeyPath void observeValueForKeyPath NSString keyPath ofObject id object change NSDictionary change context void.. addObserver self forKeyPath @ operations options 0 context NULL Then do this in your observeValueForKeyPath void observeValueForKeyPath NSString keyPath ofObject id object change NSDictionary change context void context if object self.queue..

What's the nicest way to do observer/observable in objective-c (iphone version)

http://stackoverflow.com/questions/165790/whats-the-nicest-way-to-do-observer-observable-in-objective-c-iphone-version

the nicest way to do observer observable in objective c iphone version I'm used to coding Java Swing UIs and in those if you have some properties that.. Swing UIs and in those if you have some properties that change and you want your UI to update you would implement the observer observable pattern. In Java you do this normally by having your class maintain a list of listeners that it notifies of.. in Cocoa Key Value Observing and notifications. In neither system do you need to maintain or notify a collection of observers yourself the framework will handle that for you. Key Value Observing KVO lets you observe a property of an object including..

Display keyboard without animation

http://stackoverflow.com/questions/1851566/display-keyboard-without-animation

duration so there is now way to change it easily. One way to make the keyboard appear without animation is to observe the keyboard notifications and disable animation when it's about to appear and then reenable them. This of course disables..

Help debugging iPhone app - EXC_BAD_ACCESS

http://stackoverflow.com/questions/2024266/help-debugging-iphone-app-exc-bad-access

after a memory error suggests that a UIViewController has released its view. Do you have any UIViewControllers that observe NSNotifications or otherwise might change their IBOutlets while they are off screen This is a common cause of this kind..

Delegates Vs. Notifications in iPhoneOS

http://stackoverflow.com/questions/2232694/delegates-vs-notifications-in-iphoneos

is a good thing. Notifications might be a little easier to code and offer the advantage that multiple objects can observe one notification. With delegates such a thing cannot be done without modifying the delegating object and is unusual . Some.. you can use multiple notification names but all notifications end up in the same method on the side of the observer possibly requiring a nasty switch statement . Only you can decide what pattern is more appropriate for you. In any case.. the delegate message. In many cases the view controller should change the model and then the model should inform its observers or its delegate that it has been changed. Implementing a delegate pattern is simple In your ChildViewController.h declare..

How does undo/redo basically work on iPhone OS?

http://stackoverflow.com/questions/2449268/how-does-undo-redo-basically-work-on-iphone-os

a stack of NSInvocations which are the opposite actions to any edits or other changes you make. For example void observeValueForKeyPath NSString keyPath ofObject id object change NSDictionary change context void context NSUndoManager undo.. ofObject object toValue oldValue Set the undo action name in the menu undo setActionName @ Edit can be used to observe changes in properties creating inverse NSInvocations that will undo edits to those properties. Core Data is not needed for..

Problem dealloc'ing memory used by UIImageViews with fairly large image in an UIScrollView

http://stackoverflow.com/questions/289360/problem-deallocing-memory-used-by-uiimageviews-with-fairly-large-image-in-an-ui

is to the UIScrollView. I'm using a property nonatomic retain for this and sythesizing it. My question is this When I observe this in Memory Monitor I can see that the memory used goes up quite a bit when the view with all these images is loaded..

Key Value Observing with an NSArray

http://stackoverflow.com/questions/3478451/key-value-observing-with-an-nsarray

if I have a GameModel which represents its player names with an NSArray playerNameArray of NSStrings . I want to observe those strings the view controller observes the model's data to update various things in the view. How do I get notification.. its player names with an NSArray playerNameArray of NSStrings . I want to observe those strings the view controller observes the model's data to update various things in the view. How do I get notification that the player name array has changed.. c nsarray key value observing nsarraycontroller share improve this question You don't need an NSArrayController to observe changes to an NSArray . However you cannot directly observe these changes i.e. you can't call addObserver forKeyPath options..

Pre-buffering for AVQueuePlayer

http://stackoverflow.com/questions/4218090/pre-buffering-for-avqueueplayer

item is about to finish playing I know there's nothing in the docs to suggest this I'm asking mostly if anyone has observed this kind of behavior or not. iphone objective c avfoundation avplayer share improve this question Ok I've looked.. written some code to check out AVQueuePlayer . jollyCocoa's answer pointed me in the right direction by suggesting to observe the status property on AVPlayerItem . However the documentation doesn't seem to point out that this property and it's AVPlayerItemStatusReadyToPlay..

Use Key Value Observing to get a KVO callback on a UIView's frame

http://stackoverflow.com/questions/4874288/use-key-value-observing-to-get-a-kvo-callback-on-a-uiviews-frame

ios objective c uiview key value observing share improve this question Currently it's not possible to use KVO to observe a view's frame. Properties have to be KVO compliant to be observable. Sadly properties of the UIKit framework are generally..

Customize the Airplay button's appearance

http://stackoverflow.com/questions/5174204/customize-the-airplay-buttons-appearance

addObserver self forKeyPath @ alpha options NSKeyValueObservingOptionNew context nil volumeView sizeToFit Then I observe the changed value of the buttons alpha . void observeValueForKeyPath NSString keyPath ofObject id object change NSDictionary.. context nil volumeView sizeToFit Then I observe the changed value of the buttons alpha . void observeValueForKeyPath NSString keyPath ofObject id object change NSDictionary change context void context if object isKindOfClass.. UIButton object setBounds CGRectMake 0 0 kDefaultIconSize kDefaultIconSize Don't forget to remove the observer if you destroy the button void dealloc self.airplayButton removeObserver self forKeyPath @ alpha Based on code observation..

Calling method in current view controller from App Delegate in iOS

http://stackoverflow.com/questions/5873450/calling-method-in-current-view-controller-from-app-delegate-in-ios

a notification NSNotificationCenter defaultCenter postNotificationName @ refreshView object nil In your viewController observe for this notification. You do it by adding this code to your init or viewDidLoad method NSNotificationCenter defaultCenter..

Unhiding a view is very slow in CTCallCenter callEventHandler

http://stackoverflow.com/questions/6274642/unhiding-a-view-is-very-slow-in-ctcallcenter-calleventhandler

that when a callState changes I post a notification with a userInfo dict containing the call.callState. In my view I observe this notification and when the userInfo dict contains a value of CTCallDisconnected I want to unhide a view. The problem..

Need an API that detects when an iPhone is plugged in

http://stackoverflow.com/questions/7301680/need-an-api-that-detects-when-an-iphone-is-plugged-in

Incorrect number of objects getting added to mutable array

http://stackoverflow.com/questions/9091647/incorrect-number-of-objects-getting-added-to-mutable-array

return cell Now when I am trying to print the array using the following statement NSLog @ Fields @ fields I could observe the following in console window Fields UITextField 0x9d043a0 frame 15 12 300 24 clipsToBounds YES opaque NO tag 101 layer.. 0x5c7c920 UITextField 0x9d08b20 frame 15 12 300 24 clipsToBounds YES opaque NO layer CALayer 0x9d08af0 Now as we can observe from the above o p that number of fields that are getting printed is 5 i.e the 4 textfields and the cell with button But.. null values in 5th and 7th locations of table view when printing in console.In the above implementation snippet we can observe that I have inserted using the index location to that of table view section values indices . When I save according to section..

Load all cells in UITableView before scrolling

http://stackoverflow.com/questions/9414746/load-all-cells-in-uitableview-before-scrolling

displayed it through logging in console i.e. there are 4 objects in the array Now after scrolling the table view I can observe the following there are 6 objects in the array So what's happening is If I am to save the data entered in the table view..