I created a simple application which uses UIActivityViewController as below.
let text = "Test Text"
let printData = UISimpleTextPrintFormatter(text: text)
let vc = UIActivityViewController(activityItems: [text, printData], applicationActivities: nil)
vc.completionWithItemsHandler = { (type,completed,items,error) in
print("completed. type=\(type) completed=\(completed) items=\(items) error=\(error)")
}
vc.modalPresentationStyle = .popover
vc.popoverPresentationController?.sourceView = self.openActivityButton
vc.popoverPresentationController?.sourceRect = self.openActivityButton.bounds
vc.popoverPresentationController?.permittedArrowDirections = .up
vc.popoverPresentationController?.delegate = self
self.present(vc, animated: true) { () in
}
and I run this application on iOS 10 (Xcode 8.0 beta 6).
When I close activity dialog, the completionWithItemsHandler is called.
When I select "Copy" activity, the completionWithItemsHandler is called.
When I select "Mail" activity and cancel it, the completionWithItemsHandler is called.
But, when I select "Print" activity and cancel it, the completionWithItemsHandler is not called.
This strange behavior occurred on iOS 10 but not occurred on iOS9 (the handler was called on iOS9)
Is this iOS 10's bug? If so, are there any workarounds to detect the UIActivityController is dismissed?
I pushed this sample app on https://github.com/kunichiko/ios10-activity-bug
I had a similar problem. In my case, I noticed that the completion handler was not called because the UIActivityController was already dismissed and deallocated. What I did was just add a property to hold a strong reference and set it to nil later. Then the completion handler was called properly.
Related
How do I create a timer in Godot which destroys the script's object after a given amount of time? I am looking to remove bullets from a game after a while to reduce lag.
There is a Timer node that you can use. You can add it as a child, set the wait time (in seconds) - you probably to set it as one shot and auto start - connect the "timeout" signal to your script, and on the method call queue_free to have the Node (and children, which includes the Timer) freed safely.
You can do that from code too, if that is what you prefer. So, let us go over what I just said, but instead of doing it from the editor, let us see the equivalent code:
Create a Timer, add it as a child:
var timer := Timer.new()
add_child(timer)
Set the wait time (in seconds):
timer.wait_time = 1.0
Set as oneshot:
timer.one_shot = true
Instead of setting it to auto start (which would be timer.autostart = true, let us start it:
timer.start()
Connect the "timeout" signal to a method. In this case, I'll call the method "_on_timer_timeout":
timer.connect("timeout", self, "_on_timer_timeout")
func _on_timer_timeout() -> void:
pass
Then in that method _on_timer_timeout, call queue_free:
timer.connect("timeout", self, "_on_timer_timeout")
func _on_timer_timeout() -> void:
queue_free()
You may want to use the SceneTreeTimer, like in the following code:
func die(delay: float):
yield(get_tree().create_timer(delay), "timeout")
queue_free()
Please refer to Godot Engine's documentation.
In Godot 4, there's an easier way to do this:
# Do some action
await get_tree().create_timer(1.0).timeout # waits for 1 second
# Do something afterwards
queue_free() # Deletes this node (self) at the end of the frame
However, if you do this in the _process() or _physics_process() functions, more timers get created every frame, which causes several runs to occur all at once before then running the following code. To handle this, simply track whether a timed event is happening.
Example in the _process() with simple attack logic:
var attack_started = false;
func _process(delta):
if attack_started:
print("Not attacking, attack code running in background")
return
else:
attack_started = true
prepare_attack()
await get_tree().create_timer(1.0).timeout # wait for 1 second
begin_attack()
attack_started = false
This await keyword works with everything that emits signals, including collision events!
FYI: yield was replaced with await in Godot 4, and await really just waits for a signal/callback to complete:
await object.signal
get_tree().create_timer(5.0) will create a timer that runs for 5 seconds, and then has a timeout callback/signal you can tap into.
I have a music app that uses the MPMusicPlayerController.
I originally wrote it using the systemMusicPlayer option under iOS 9.
I had some trouble with the player not shutting down correctly under certain circumstances so I switched to the appplicationMusicPlayer
(see Quitting app causes error "Message from debugger: Terminated due to signal 9")
However, as an application player, I can't get a lot of the benefits like control center handling, bluetooth data display, etc.
So, I switched back to the systemMusicPlayer.
I have also changed to Xcode 9.2 and a compile target of iOS 10.3.
Now when I run my app, it can take several seconds for it to respond to controls like play/pause or next/previous. My whole UI is painfully unresponsive.
I tried switching back to applicationMusicPlayer, recompiled, and sure enough - the UI is at normal speed.
So now I'm in a crappy position - with systemMusicPlayer, the app is barely usable, but with applicationMusicPlayer I lose a ton of capabilities.
This seems directly related to either iOS 11.2.2 on my iPhone, or something to do with targeting iOS 10.3+
Does anyone have any information about what is going on and how to fix it
EDIT:
I created a very basic player and it seems to work fine in either mode, so now I'm puzzled - I'll be testing other MP commands to see what the
issue is but since even my UI slows down I'm not sure.
EDIT 2:
I believe I've found the culprit to be NotificationCenter, and also getting States from the MPMusicPlayerController. I've updated my sample code below which shows the problem. Once running, clicking the 'next' button will be slow sometimes, but clicking 'previous' can cause delays of up to two seconds!!
Here is the basic code if you want to create a simple player.
Be sure to add three buttons in the storyboard and connect them accordingly.
//
// ViewController.swift
// junkplayer
//
import UIKit
import MediaPlayer
let notificationCenter = NotificationCenter.default
let myMP:MPMusicPlayerController = MPMusicPlayerController.systemMusicPlayer
//let myMP:MPMusicPlayerController = MPMusicPlayerController.applicationMusicPlayer()
class ViewController: UIViewController {
#IBOutlet weak var xxx: UIButton!
#IBOutlet weak var nextbut: UIButton!
#IBOutlet weak var prevbut: UIButton!
var qrySongs = MPMediaQuery()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
myMP.repeatMode = MPMusicRepeatMode.none
myMP.shuffleMode = MPMusicShuffleMode.off
myMP.prepareToPlay()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
stopMPNotifications()
startMPNotifications()
}
#IBAction func nextbut(_ sender: Any) {
myMP.skipToNextItem()
}
#IBAction func prevbut(_ sender: Any) {
myMP.skipToPreviousItem()
}
#IBAction func playbut(_ sender: UIButton) {
qrySongs = MPMediaQuery.songs()
myMP.setQueue(with: qrySongs)
myMP.play()
}
func startMPNotifications(){
notificationCenter.addObserver(self, selector: #selector(showNowPlaying), name: .MPMusicPlayerControllerNowPlayingItemDidChange, object: myMP)
notificationCenter.addObserver(self, selector: #selector(handlePlayState), name: .MPMusicPlayerControllerPlaybackStateDidChange, object: myMP)
myMP.beginGeneratingPlaybackNotifications()
}
func stopMPNotifications(){
notificationCenter.removeObserver(self, name: .MPMusicPlayerControllerPlaybackStateDidChange, object: myMP)
notificationCenter.removeObserver(self, name: .MPMusicPlayerControllerNowPlayingItemDidChange, object: myMP)
myMP.endGeneratingPlaybackNotifications()
}
#objc func handlePlayState(){
if myMP.playbackState == .playing {
print("handlePlayState playback state = playing")
}else{
print("handlePlayState playback state NOT playing")
}
print("handlePlayState going to shownowplaying")
showNowPlaying()
}
#objc func showNowPlaying(){
if myMP.nowPlayingItem != nil {
print("shownowplaying nowplaying not null")
}
}
}
The app seems to lock up once you start playing, but if you swipe up to show the Control Centre then dismiss it, the app starts working fine immediately.
I am having the same problem. I think it’s something wrong with the API. It's especially slow for large queries. But you can put a predicate on the quart, that allows no cloud music to go on it.
For anyone browsing this thread in the future, this was a known bug within all versions of iOS 11.2. It affected anyone using the systemMusicPlayer.
Apple sure does love to discourage us third party music app developers, eh? ;)
Regardless of my conspiracy theories (and I'm sure you have yours too), this bug was fixed in iOS 11.3.
We warn users on iOS 11.2 about the bug and recommend that they upgrade to iOS 11.3 for a (more or less) lag-free experience.
I ran into this problem today - working code just stopped running correctly, but I found a (partial) workaround:
\\Do anything that updates (like changing the song title in the UI) in the selector called by this notification
NotificationCenter.default.addObserver(self, selector: #selector(remoteMusicChange), name: NSNotification.Name.MPMusicPlayerControllerNowPlayingItemDidChange, object: nil)
The issue is that calls to say go to the next track for systemMusicPlayer are no longer (always) happening immediately. If you wait for the notification, at least you can be sure systemMusicPlayer has updated.
The problem with this is sometimes it can take a perceptibly long time for that notification to fire (and sometimes it's instant).
EDIT: https://forums.developer.apple.com/thread/96287 I am guessing this is related to these issues
EDIT2: Tested another related issue quickly in iOS12 and the problem no longer existed (changing playback speed) and the pauses when changing songs went away.
We have a WPF app that also runs on a tablet. We are targeting Windows 10, .Net 4.6.2.
We have an async event handler that calls MessageBox.Show. The user clicks Yes and the app continues on doing some stuff.
When the app runs on tablet hardware, the app locks up for 10-20 seconds after the event completes. I cannot duplicate this from the desktop or in the simulator, only when it actually runs on the tablet.
I have isolated it to the MessageBox. When I take it out the app behaves normally. I feel like maybe it has something to do with threading.
Any ideas?
using "async" will cause the MesssageBox.Show() method to be called on a separate thread. instead of putting the MesssageBox.Show() call in an async call consider putting it in a Thread, ensuring you declare it a background thread:
Thread messageBoxThread = new Thread(() => { yourMessageBoxCall(); );
messageBoxThread.IsBackground = true;
messageBoxThread.Start();
Based on #stuicidle's clue, I went down a better research path. Many people have tried to solve the async MessageBox problem.
I ultimately got my solution from how can i use Messagebox.Show in async method on Windows Phone 8?
My code looks like this:
private async Task HandleEvent()
{
var message = $"Continue?";
MessageBoxResult result = MessageBoxResult.None;
var dg = new Action(() => result = MessageBox.Show(message, "Warning", MessageBoxButton.YesNo));
await Dispatcher.BeginInvoke(dg);
if (result == MessageBoxResult.Yes)
await DoSomeStuff();
}
I am having a strange issue with MVVM Light messaging. I am using it through my application and it has worked fine. I am now having a problem where my message is received roughly 10% of the time I try to send it. I'm assuming it gets shot off in to oblivion the other 90% of the time and I receive no errors and my application goes on as if nothing happened.
What I have is a context menu in a view that has a collection of statuses. Each user has a status and you can change it via this context menu. Every time the status changes I need to broadcast a message to another view model. This is the message that fails. Here is some code, feel free to ask me more questions if this is not clear enough for you.
This is located in my constructor, fired from a context menu item click:
this.UpdateUserStatus = new RelayCommand<UserStatusVM>(x =>
DispatcherHelper.CheckBeginInvokeOnUI(() =>
{
UpdateStatus(x);
}));
UpdateStatus method from relay command:
private void UpdateStatus(UserStatusVM status)
{
var userStatusEventId = _userService.CreateUserEvent(status.Id, CurrentUser.Id);
//This returns a business object that I would like to send
//over the wire to the other view model
var userEvent = _userService.GetUserEvent(userStatusEventId);
if (userEvent != null)
{
Messenger.Default.Send<UserEvent>(userEvent, "Broadcast");
}
//These fire off a collection changed event
CurrentUser.StatusId = status.Id;
CurrentUser.Status = status.Name;
CurrentUser.UpdatedDate = DateTime.Now;
CurrentUser.IsOnDuty = UserStatuses.IsOnDuty(status.Id);
}
and the message reception in the other view model:
Messenger.Default.Register<UserEvent>(this, "Broadcast", (userEvent) =>
{
proxy.Invoke("NewUserEvent", userEvent);
});
I am developing a windows form application. Following is the code segment that is executed on a button click event.
var taskExecute= Task<Datatable>.Run(() =>
{
return = GetDt(); // time consuming method
})
.ContinueWith(task=>
{
this.datagridVal.Datasource = task.Result;
}, TaskScheduler.FromCurrentSynchronizationContext());
this works fine. But If I start the thread and then immediately click on the cross(x) button of the form then the following line of code throws NullReferenceException (most probably because the form has been already disposed and so is the datagrid control)
this.datagridVal.Datasource = task.Result;
How can I modify the code so that this block of code does not throw any exception if the form is closed when the thread is running? Also please suggest if there is any better way to handle the scenario using
If the problem indeed comes from the fact that the form is disposed, then you could handle that with this.IsDisposed:
var taskExecute= Task<Datatable>.Run(() =>
{
return = GetDt(); // time consuming method
})
.ContinueWith(task=>
{
if (!this.IsDisposed)
{
this.datagridVal.Datasource = task.Result;
}
}, TaskScheduler.FromCurrentSynchronizationContext());