I'm currently trying to get NSNotification to work but I'm having some trouble.
I have two (2) ViewControllers: A. MainViewController & B. LoginViewController.
In my MainViewController I have a logout button that will send a url to my LoginViewController to load it (without showing my loginView). However, it's not working.
In my MainViewController this is what I have:
- (IBAction)logout:(id)sender {
NSURL *logoutURL = [NSURL URLWithString:#"https://myurl.com/logout"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"logoutInitiated" object:logoutURL];
}
This is what I have in my LoginViewController:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
WebView.delegate = self;
WebView.scalesPageToFit = YES;
WebView.multipleTouchEnabled = YES;
loadCount = 0;
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(submitLogout) name:#"logoutInitiated" object:nil];
}
- (IBAction)submitLogout:(NSNotification*)notification {
[WebView stopLoading];
NSURL * signOutUrl = (NSURL*)[notification object];
[self loadURL:nil withURL:signOutUrl];
}
My problem is that when I press the logoutButton nothing happens. (Using NSLogs, I see that it never triggers the next step) Thank you!!!!
This is because your method name you are passing in selector is wrong. You need to add colon : at submitLogout: suffix
Use
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(submitLogout:) name:#"logoutInitiated" object:nil];
in place of
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(submitLogout) name:#"logoutInitiated" object:nil];
Hope it helps you.
When you add self as an observer, you use the selector "submitLogout" without a semicolon! But your method has an argument, so the correct selector would be #selector(submitLogout:).
Note the SEMICOLON
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(**submitLogout:**) name:#"logoutInitiated" object:nil];
- (IBAction)logout:(id)sender
{
NSURL *logoutURL = [NSURL URLWithString:#"https://myurl.com/logout"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"logoutInitiated" object:nil userInfo:[NSDictionary dictionaryWithObjectsAndKeys:logoutURL,#"RECEIVED_URL", nil]];
}
- (IBAction)submitLogout:(NSNotification*)notification
{
[WebView stopLoading];
NSURL * signOutUrl = (NSURL*)[notification objectForKey:#"RECEIVED_URL"];
[self loadURL:nil withURL:signOutUrl];
}
Related
hello i assign nsnotifiaction in app delegate.m's method and this method call eprox every 30sec, and i wants its notifcation in viewcontroller adn execute method,
here is my code of appdelegate .m
- (void)layoutAnimated:(BOOL)animated{
BOOL yy= self.bannerView.bannerLoaded;
if (yy==1){
self.iAdString=[NSMutableString stringWithString:#"1"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"BannerViewActionWillBegin" object:self];
}
else{
self.iAdString=[NSMutableString stringWithString:#"0"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"BannerViewActionDidFinish" object:self];
}
}
and in viewcontroller.m
//i defined in viewdidload method
- (void)viewDidLoad{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(willBeginBannerViewActionNotification:) name:#"BannerViewActionWillBegin "object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(didFinishBannerViewActionNotification:) name:#"BannerViewActionDidFinish" object:nil];
}
its method are..
- (void)willBeginBannerViewActionNotification:(NSNotification *)notification{
[self.view addSubview:self.app.bannerView];
NSLog(#"come");
}
- (void)didFinishBannerViewActionNotification:(NSNotification *)notification {
NSLog(#"come");
[self.app.bannerView removeFromSuperview];
}
- (void)dealloc{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
I have not getting response of excessing method while method read in appdelegate file.
Please help me.
You have a typo error.
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(willBeginBannerViewActionNotification:) name:#"BannerViewActionWillBegin "object:nil];
//Your error here-------------------------------------------------------------------------------------------------------------------------------------^
You have put a space there.
SideNote: For all notification names, you should/can create a separate file and put all your notification names as constants strings.
const NSString *kBannerViewActionWillBegin=#"BannerViewActionWillBegin";
this will be easier to change the value and no such typo will happen.
From your code what I get is except for the notification name's all other stuff is fine, did you check whether the notification gets fired. Try keeping break points at the notification firing line.
I have a UISwitchcontroller in my setting page to change the image in main page. So I put a notification from setting page to main page. But only one notification I active every time, my setting page switch code look like this:
-(IBAction)_clickswitchlowlight:(id)sender
{
if(switchControll.on){
[switchControll setOn:YES animated:YES];
[[NSNotificationCenter defaultCenter] postNotificationName:NOTIF_lowlighton object:nil];
}
else{
[switchControll setOn:NO animated:YES];
[[NSNotificationCenter defaultCenter] postNotificationName:NOTIF_lowlightoff object:nil];
}
}
In my main page.h..I write this code:
extern NSString * const NOTIF_lowlighton;
extern NSString * const NOTIF_lowlightoff;
In .m above the implementation of main page I write this:
NSString * const NOTIF_lowlighton = #"lowlighton";
NSString * const NOTIF_lowlightoff = #"lowlightoff";
In viewwillappear I write this code:
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(clicklowlighton:) name:#"lowlighton" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(clicklowlightoff:) name:#"lowlightoff" object:nil];
}
Then this code for changing the image:
- (void)clicklowlighton:(NSNotification *)notif
{
[[self multiPageView] setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:#"bgipad"]]];
}
- (void)clicklowlightoff:(NSNotification *)notif
{
[[self multiPageView] setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:#"bglowlight#2x"]]];
}
I only get the clicklowlightoff notification, I didn't get the first notification...any missing in my code?
bind your function to event: UIControlEventValueChanged to this function
-(IBAction)_clickswitchlowlight:(id)sender
{
if(switchControll.on){
[[NSNotificationCenter defaultCenter] postNotificationName:NOTIF_lowlighton object:nil];
}
else{
[[NSNotificationCenter defaultCenter] postNotificationName:NOTIF_lowlightoff object:nil];
}
}
How do I find out if the keyboard is up?
I have a UISearchbar instance which becomes the first responder.
When the keyboard appears a notification is sent out as part of the API, however I don't want to respond to this right away. I could record this in a boolean state, but that seems clunky. I'd like to know if there is a "getter" some where I can call to find out.
This is how I do it:
KeyboardStateListener.h
#interface KeyboardStateListener : NSObject {
BOOL _isVisible;
}
+ (KeyboardStateListener *) sharedInstance;
#property (nonatomic, readonly, getter=isVisible) BOOL visible;
#end
KeyboardStateListener.m
#import "KeyboardStateListener.h"
static KeyboardStateListener *sharedObj;
#implementation KeyboardStateListener
+ (KeyboardStateListener *)sharedInstance
{
return sharedObj;
}
+ (void)load
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
sharedObj = [[self alloc] init];
[pool release];
}
- (BOOL)isVisible
{
return _isVisible;
}
- (void)didShow
{
_isVisible = YES;
}
- (void)didHide
{
_isVisible = NO;
}
- (id)init
{
if ((self = [super init])) {
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self selector:#selector(didShow) name:UIKeyboardDidShowNotification object:nil];
[center addObserver:self selector:#selector(didHide) name:UIKeyboardWillHideNotification object:nil];
}
return self;
}
-(void) dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
[super dealloc];
}
#end
Then use this to figure out the rest:
KeyboardStateListener *obj = [KeyboardStateListener sharedInstance];
if ([obj isVisible]) {
//Keyboard is up
}
The only sure way that I can think to do it as you said. using notifications like this:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
and then
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
Other than that, you may be able to iterate through your views subviews and look for the keyboard like:
UIView *keyboard = nil;
for (UIView *potentialKeyboard in [myWindow subviews]) {
// iOS 4
if ([[potentialKeyboard description] hasPrefix:#"<UIPeripheralHostView"]) {
potentialKeyboard = [[potentialKeyboard subviews] objectAtIndex:0];
}
if ([[potentialKeyboard description] hasPrefix:#"<UIKeyboard"]) {
keyboard = potentialKeyboard;
break;
}
}
But I am not sure if this will break when the SDK changes ...
Maybe use this method and add a category to the window so that you can just always ask the window for the keyboard ... just a thought.
How to implement to get UIAccessibilityVoiceOverStatusChanged Notification?
I tried like below but nothing happens :
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:#selector(notified:) name:UIAccessibilityVoiceOverStatusChanged object:self];
That looks reasonable, except maybe object:self should be object:nil?
The other thing is to be sure your signature is correct:
- (void)voiceOverStatusChanged: (NSNotification *)notification;
I think you might try adding the observer in the awakeFromNib method with the right selector signature.
Something like this will work
- (void)awakeFromNib {
[super awakeFromNib];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(voiceOverChanged)
name:UIAccessibilityVoiceOverStatusChanged
object:nil];
[self voiceOverChanged];
}
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIAccessibilityVoiceOverStatusChanged object:nil];
}
- (void)voiceOverChanged {
// Your actions here
}
you can get the UIAccessibilityVoiceOverStatusChanged Notification with the code
- (void)viewDidLoad {
[super viewDidLoad];
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:#selector(didChangeVoiceOverStatus:)
name:UIAccessibilityVoiceOverStatusChanged
object:nil];
}
- (void)didChangeVoiceOverStatus:(NSNotification *)notification {
if (UIAccessibilityIsVoiceOverRunning()) {
NSLog(#"VoiceOver is ON.");
} else {
NSLog(#"VoiceOver is OFF.");
}
}
Here's the code:
- (void)viewDidLoad
{
[super viewDidLoad];
NSURL *musicURL = [NSURL URLWithString:#"http://live-three2.dmd2.ch/buureradio/buureradio.m3u"];
if([musicURL scheme])
{
MPMoviePlayerController *mp = [[MPMoviePlayerController alloc] initWithContentURL:musicURL];
if (mp)
{
// save the music player object
self.musicPlayer = mp;
[mp release];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(popBack:) name:#"MPMoviePlayerDidExitFullscreenNotification" object:nil];
// Play the music!
[self.musicPlayer play];
}
}
}
-(void)popBack:(NSNotification *)note
{
[self.navigationController popToRootViewControllerAnimated:YES];
}
The selector method never gets called. I just want to pop back to the root menu when the "Done" button is pressed on the movie player. I put an NSLog in the selector to check if it was even being called, nothing. The music plays fine. Any thoughts?
This should work
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(popBack:) name:MPMoviePlayerPlaybackDidFinishNotification object:nil];