what is wrong with this method?
- (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame {
[activityIndicator stopAnimation:self];
}
I want to stop the Circular Progress Indicator (activityIndicator). But there is something wrong with - (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame. I am coding for mac osx and not for iOS. I heard something from Delegates, what does that mean?
Check to be sure that your UIWebView has set its delegate. Setting a delegate is basically telling the program who you want to handle events (like taps, gestures, or, in this case, the loading of a webView). Thus when an event is fired, it will inform the delegate and the delegate can process it. Maybe if you post more of your code it would help, but I would check your declaration of the UIWebView in question. Be sure that after you allocate it and initialize it, you set its delegate to self (assuming that this method is in the same class), like so:
UIWebView *myWebView = [[UIWebView alloc] init];
[myWebView setDelegate:self];
If you have not set the delegate, it is firing off events and no one is receiving them to process them. The method you are using is waiting for the specific event sent by any webView. When it is sent an event message it passes, as a parameter, the webView that triggered. In any case, put in a log statement to be sure you are entering the method. That will tell you if it is receiving the event messages.
- (void)webView:(WebView *)sender didFinishLoadForFrame:(WebFrame *)frame {
NSLog(#"Did finish loading...");
[activityIndicator stopAnimation:self];
}
NOTE: This is as per iOS experience, but should work for Mac OS as well. Let me know what your log result is, if the method is getting called or not.
Related
This seems like it should be pretty straight-forward but I'm having trouble finding a working example, good documentation, or even many StackOverflow posts that are helpful.
I have a custom view which contains an AVPlayer, like so:
#implementation
{
#private
AVPlayerViewController *controller
}
- (id) init
{
self = [super init];
if (self)
{
controller = [[AVPlayerViewController alloc] init];
controller.view.frame = self.view.bounds;
[self.view addSubview:controller.view];
}
return self;
}
#end
(I have a few other views like a message that overlays the player, a poster that I display while swapping videos, etc - but this is the basic setup)
When I integrated the IMA SDK, I started to have issues. If you press the pause button on the remote control during an ad, it pauses the ad just fine. But if you press the pause button again it doesn't unpause the ad, but instead unpauses my content player behind the ad. I don't hear any audio, but I know the content player was unpaused because I have ID3 metadata in my video and an NSLog() statement when I hit it, and I begin to see these logs. If I press the pause button again, the logs pause. I press it a fourth time, the logs start up again.
To try and fix this I wanted to bind a listener to the remote's play/pause button and make sure that if I was playing an ad then the ad was resumed, not the content. So I tried adding the following to my init method on my view:
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self.view action:#selector(tapped:)];
[tapRecognizer setAllowedPressTypes:#[ [NSNumber numberWithInt:UIPressTypePlayPause] ]];
[self.view addGestureRecognizer:tapRecognizer];
I then created the following method:
- (void) tapped: (UITapGestureRecognizer *) sender
{
NSLog(#"Tapped");
}
This isn't being called. I'm pretty confident I made a simple mistake, but the documentation isn't very clear, so I'm not sure what I should be doing instead. The official documentation on detecting button presses uses Swift and says:
let tapRecognizer = UITapGestureRecognizer(target: self, action: "tapped:")
tapRecognizer.allowedPressTypes = [NSNumber(integer: UIPressType.PlayPause.rawValue)];
self.view.addGestureRecognizer(tapRecognizer)
I believe I translated those three lines well. The documentation then doesn't show what the tapped method should look like, but instead goes on a tangent about working with low-level event handling. So to get the appropriate method signature I looked at the documentation on UITagGestureRecognizer which had the following (Swift) example for writing a handler:
func handleTap(sender: UITapGestureRecognizer) {
if sender.state == .ended {
// handling code
}
}
This is why I went with - (void) tapped: (UITapGestureRecognizer *) sender
Still, after all of that, it's not working.
Quick Update
I tried replacing:
initWithTarget:self.view
With:
initWithTarget:controller.view
And:
self.view addGestureRecognizer
With:
controller.view addGestureRecognizer
And this time it looks like something actually happened when I pressed the play/pause button. The app crashed and Xcode gave me the following error:
2019-12-17 12:16:50.937007-0500 Example tvOS App[381:48776] -[_AVPlayerViewControllerContainerView tapped:]: unrecognized selector sent to instance 0x10194e060
So it seems like (correct me if I'm wrong):
The AVPlayerViewController has the focus, not my view
The gesture recognizer calls the selector on whatever class you register it to, rather than the class that did the registering
So I guess an alternative question to my original would be: How do I allow my class to handle a gesture on some other class (e.g. AVPlayerViewController)?
The target does not need to equal the view that the gesture recognizer is attached to. You can set the target to MyView but still attach the gesture recognizer to controller.view
To work around the unrecognized selector crash, you need to make sure you're providing the correct object as the target for your gesture recognizer. The way UIGestureRecognizer works is that when the gesture is recognized, it will invoke the given selector on the given target object. In other words, when gesture fires, it's going to perform the equivalent of:
[target selector:self];
(You seem to be treating the target as the view that the gesture will be attached to, which isn't how it works)
So if you implemented tapped: on your class MyView, then the target you pass to the gesture recognizer initializer should be an instance of MyView. You probably want to provide self, not self.view.
The WatchApp receives data from the iPhone.
I refresh the label text with the data received, nothing happens, the UI is not refreshing.
Other threads suggested pushing it to the main thread and that seems to do nothing either.
Any thoughts most welcome.
-(void)session:(nonnull WCSession *)session didReceiveApplicationContext:(nonnull NSDictionary *)applicationContext
{
dispatch_async(dispatch_get_main_queue(), ^{
[self.lblTitleBorH setText:#"test"];
});
}
Are you using
[*your session* updateApplicationContext:*your dictionary* error:nil];
correctly?
try putting a NSLog inside your above didReceiveApplicationContext code and see if it is printing anything out.
In my case, when I tried to refresh the UI, I found that the outlet references were nil. The problem was caused by two interfaces on the storyboard, belonging to the same WKInterfaceController class.
When I assigned the second screen interface to another WKInterfaceController class it worked fine.
remember to call the UI objects from the main thread by using
dispatch_async(dispatch_get_main_queue(), ^{
...
});
or by using methods like performSelectorOnMainThread: withObject: waitUntilDone:
I am about to implement a simple audio fader.
I subclassed NSSlider and NSSliderCell to be able to draw the graphics accordingly.
I want the slider to jump to a defined position whenever the handle is clicked with the Cmd key pressed. This is pretty common in most audio applications.
Setting the value to the slider is working flawlessly, but it does not invoke the action method to inform my target that the value changed.
This must be happening somewhere in the mouseDown event handling of "super", probably in NSControl. This is what I got so far :
- (void) mouseDown:(NSEvent *)theEvent
{
if ( ([theEvent modifierFlags] & NSCommandKeyMask) > 0)
[self setFloatValue:100.0f];
else
[super mouseDown:theEvent];
}
I found a method in the NSControl doc that looks promising:
-(BOOL)sendAction:(SEL)theAction to:(id)theTarget Parameters :
theAction : The selector to invoke on the target. If the selector is
NULL, no message is sent.
theTarget : The target object to receive the message. If the object is
nil, the application searches the responder chain for an object
capable of handling the message. For more information on dispatching
actions, see the class description for NSActionCell.
But I don't have a clue what the selector would be named like.
The target would probably be super?
Any help is much appreciated!!
Best,
Flo
The action could be the name of the action method that you already are using for your slider, and the target should be the class instance where that method is implemented. So, for example, if you had an IBAction in your app delegate that was connected to your slider called sliderReport: then do this:
[self sendAction:#selector(sliderReport:) to:[NSApp delegate]];
Additional Note: I assumed from your question that you wanted to invoke the same IBAction that you have connected to your slider, but you could send a different selector if you want -- if you need to distinguish between how the slider value was changed, having a different method would be the way to go. You can name it anything you want (with a colon on the end, so it can send itself as the sender argument if you need that).
I found an answer myself.
Although the answer of #rdelmar might also work, it won't anymore if you change the name of the action method.
I found a universal way of triggering the action method manually:
- (void) mouseDown:(NSEvent *)theEvent
{
if ( ([theEvent modifierFlags] & NSCommandKeyMask) != 0)
{
[self setFloatValue:100.0f];
[self.target performSelector:self.action withObject:self];
}
else
[super mouseDown:theEvent];
}
This is by far the weirdest problem I've been stuck with.
I have a UIViewController on a UINavigationController and I want to call a method at viewDidAppear using NSInvocationOperation so it can run on a back thread when the view becomes visible.
The problem is that if I pop the view controller BEFORE the operation (in this case the testMethod method) completes running, the app crashes.
Everything works fine if I pop the view controller AFTER the operation runs it's course.
When the app crashes, it stops at [super dealloc] with "EXC-BAD-ACCESS" and gives me the following error.
bool _WebTryThreadLock(bool), xxxxxxxxx: Tried to obtain the web lock
from a thread other than the main thread or the web thread. This may
be a result of calling to UIKit from a secondary thread. Crashing
now...
And this is my code (super simplified)..
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
NSInvocationOperation *theOperation = [[NSInvocationOperation alloc] initWithTarget:self selector:#selector(testMethod) object:nil];
[operationQueue addOperation:theOperation];
[theOperation release];
}
- (void)testMethod
{
NSLog(#"do some stuff that takes a few seconds to complete");
}
- (void)dealloc
{
[_tableView release];
[super dealloc];
}
The testMethod has some code that takes a few seconds to complete. I only have a few clues and I really don't know how and where to start debugging this.
Clue #1: The funniest thing is that if I remove the [_tableView release]; from dealloc then the app doesn't crash. But of course this would cause a leak and I can't remove it.
Clue #2: I've tested this code on a separate "clean" UIViewController with a UITableView and to my surprise it didn't crash.
Clue #3: The app doesn't crash is the UITableView's datasource is set to nil in viewDidLoad.
Clue #4: The app doesn't seem crash if I use the same code in viewDidAppear somewhere else like an IBAction.
Clue #5: I've tried looking over stack data with NSZombie but it gives me tons of data and it leads me nowhere.
I have some very complicated code within my UITableViewDelegate and UITableViewDataSource and I really don't know where to start debugging this. I really hope I don't have to go through line by line or rewrite the entire thing because of this.
Any pointers on where I should be looking?
The problem is likely that your view controller's last reference is the operation queue holding onto it, which means you are technically calling (or having the system call) some UIKit methods in a background thread (a big no-no) when the operation cleans up.
To prevent this from happening, you need to send a keep-alive message to your controller on the main thread at the end of your operation, by adding something like this to the last line in your testMethod:
[self performSelectorOnMainThread:#selector(description) withObject:nil waitUntilDone:NO];
There is still a chance that this message may get processed before the operation queue releases your view controller, but that chance is pretty remote. If it's still happening, you could do something like this:
[self performSelectorOnMainThread:#selector(keepAlive:)
withObject:[NSNumber numberWithBool:YES]
waitUntilDone:NO];
- (void)keepAlive:(NSNumber *)fromBackground
{
if (fromBackground)
[self performSelector:#selector(keepAlive:) withObject:nil afterDelay:1];
}
By sending a message to your view controller on the main thread, it will keep the object alive (NSObject retains your view controller until the main thread handles the message). It will also keep the view controller alive if you perform a selector after a delay.
You're crashing because the controller is still trying to use your tableView reference and since you poped the viewController, everything will go away in the dealloc and the tableView is still populating itself.
You can try asking in your dealloc method if your operation is still running, so you can cancel it and the everything should be fine.
Once you add an operation to a queue, the operation is out of your
hands. The queue takes over and handles the scheduling of that task.
However, if you decide later that you do not want to execute the
operation after all—because the user pressed a cancel button in a
progress panel or quit the application, for example—you can cancel the
operation to prevent it from consuming CPU time needlessly. You do
this by calling the cancel method of the operation object itself or by
calling the cancelAllOperations method of the NSOperationQueue class.
Cancelling an operation does not immediately force it to stop what it
is doing. Although respecting the value returned by the isCancelled is
expected of all operations, your code must explicitly check the value
returned by this method and abort as needed. The default
implementation of NSOperation does include checks for cancellation.
For example, if you cancel an operation before its start method is
called, the start method exits without starting the task.
I'm in the midst of debugging an extremely unusual problem, and I was wondering if anybody might have any insight into what might be going wrong:
In a controller class from a NIB, I take an NSPanel from that same NIB, and then show it app modally on a NSWindow (that was created by hand in code):
[[NSApplication sharedApplication] beginSheet: myPanel
modalForWindow: window
modalDelegate: self
didEndSelector: #selector(sheetDidEnd:returnCode:contextInfo:)
contextInfo: nil];
[[NSApplication sharedApplication] runModalForWindow: myPanel];
Now, when the "finish" button on that sheet is clicked, I run some code to disable some buttons and fire off a thread to make sure the user input is valid (I have to validate with a remote service). This thread is fired from a separate validator object I create:
// controller calls:
[validator validateCreds: creds
notify: #selector(validationComplete:)
onObject: self];
// validator object
validateInfo: (NSDictionary *)parms
notify: (SEL)notifySelector
onObject: (id)notifyObject
{
// build up data with parms and notify info
[[NSThread detachNewThreadSelector: #selector(remotevalidate:)
toTarget: self withObject: data];
}
Next, when the validation is finished, the validator notifies my controller object:
[notifyObject performSelectorOnMainThread: notifySelector
withObject: results waitUntilDone: NO];
And then my controller object, in the method that the validator object calls, kills the dialog:
- (void)validationComplete: (id)data
{
[[NSApplication sharedApplication] stopModal];
[createTwitterPanel orderOut: nil];
[[NSApplication sharedApplication] endSheet: createTwitterPanel
returnCode: NSOKButton];
}
- (void)sheetDidEnd:(NSWindow *)sheet
returnCode:(int)returnCode
contextInfo:(void *)contextInfo
{
m_returnCode = returnCode;
}
My problem: Although the panel is closed / disappears, the top NSApp runModalForWindow: does not exit until some system event is sent to the window that was showing the dialog. Trying to move, resize, or do anything to the window, or otherwise switching away from the application suddenly causes the method to exit and execution to continue. No amount of waiting seems to help, otherwise, however.
I have verified that all methods being invoked on the controller class are all being invoked on the main app thread.
An even more interesting clue is that the dialog has two controls, a WebView, and an NSTextField: Even if I force the exit of runModalForWindow: by clicking on the window, TABbing between the two controls remains screwed up — it simply never works again. It's like my event loop is horked.
I've tried changing validationComplete: to instead post a notification to the main thread, and I've also played with the waitUntilDone on the performSelectorOnMainThread method, all to no effect.
Any ideas? Things I should try looking at?
From the NSApplication documentation:
abortModal must be used instead of
stopModal or stopModalWithCode: when
you need to stop a modal event loop
from anywhere other than a callout
from that event loop. In other words,
if you want to stop the loop in
response to a user’s actions within
the modal window, use stopModal;
otherwise, use abortModal. For
example, use abortModal when running
in a different thread from the
Application Kit’s main thread or when
responding to an NSTimer that you have
added to the NSModalPanelRunLoopMode
mode of the default NSRunLoop.
So, I learned something today.