I am developing a network monitor app that runs in background as a service. Is it possible to get a notification/call when the screen is turned on or off?
It exists in Android by using the following code:
private void registerScreenOnOffReceiver()
{
IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
registerReceiver(screenOnOffReceiver, filter);
}
screenOnOffReceiver is then called when screen is turned on/off. Is there a similar solution for iOS?
Edit:
The best I've found so far is UIApplicationProtectedDataWillBecomeUnavailable ( Detect if iPhone screen is on/off ) but it require the user to enable Data Protection (password protection) on the device.
You can use Darwin notifications, to listen for the events. I'm not 100% sure, but it looks to me, from running on a jailbroken iOS 5.0.1 iPhone 4, that one of these events might be what you need:
com.apple.iokit.hid.displayStatus
com.apple.springboard.hasBlankedScreen
com.apple.springboard.lockstate
Update: also, the following notification is posted when the phone locks (but not when it unlocks):
com.apple.springboard.lockcomplete
To use this, register for the event like this (this registers for just one event, but if that doesn't work for you, try the others):
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
NULL, // observer
displayStatusChanged, // callback
CFSTR("com.apple.iokit.hid.displayStatus"), // event name
NULL, // object
CFNotificationSuspensionBehaviorDeliverImmediately);
where displayStatusChanged is your event callback:
static void displayStatusChanged(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo) {
NSLog(#"event received!");
// you might try inspecting the `userInfo` dictionary, to see
// if it contains any useful info
if (userInfo != nil) {
CFShow(userInfo);
}
}
If you really want this code to run in the background as a service, and you're jailbroken, I would recommend looking into iOS Launch Daemons. As opposed to an app that you simply let run in the background, a launch daemon can start automatically after a reboot, and you don't have to worry about iOS rules for apps running tasks in the background.
Let us know how this works!
Using the lower-level notify API you can query the lockstate when a notification is received:
#import <notify.h>
int notify_token;
notify_register_dispatch("com.apple.springboard.lockstate", ¬ify_token, dispatch_get_main_queue(), ^(int token) {
uint64_t state = UINT64_MAX;
notify_get_state(token, &state);
NSLog(#"com.apple.springboard.lockstate = %llu", state);
});
Of course your app will have to start a UIBackgroundTask in order to get the notifications, which limits the usefulness of this technique due to the limited runtime allowed by iOS.
While iPhone screen is locked appdelegate method
"- (void)applicationWillResignActive:(UIApplication *)application"
will be called you can check that. Hope it may help you.
Related
I would like to implement background bluetooth scanning on IOS. When the application goes in background mode it calls TestCentralManagerDelegate which implements DiscoveredPeripheral function. It is triggered when a new bluetooth peripheral device is detected. If a new bluetooth device is detected the application read the manufacture data which is presented in Dictionary advertisementData (as argument of DiscoveredPeripheral function). The manufacture data are obtained by calling ManufactureData = advertisementData["kCBAdvDataManufacturerData"].ToString(). The discovering of the manufacture data was tested on two different iPhones 5s and 6 with the same iOS 12.1. When the application goes in background mode, I locked the screen.
In the case of iPhone 5s, I observed that ManufactureData was found each time
the DiscoveredPeripheral function is triggered. This fact is not true for iPhone 6, each time I got ManufactureData = null. It is worth mentioning that the manufacture data are received in both cases if the screen is not locked.
I do not understand why the iPhone 6 does not find ManufactureData, meanwhile the iPhone 5s does. I would accept the fact that phones have different operating systems and this implies different responses, but in my case this is not the case. I will appreciate any help for better understanding aforementioned problem.
Here is code I am using Xamarin.iOS.
public override void DiscoveredPeripheral(CBCentralManager central, CBPeripheral peripheral, NSDictionary advertisementData, NSNumber RSSI)
{
try
{
central.StopScan();
if (peripheral == null || advertisementData == null)
{
central.ScanForPeripherals(cbuuids);
return;
}
string ManufactureData;
if (advertisementData.ContainsKey(new NSString("kCBAdvDataManufacturerData")))
{
ManufactureData = advertisementData["kCBAdvDataManufacturerData"].ToString();
}
else
{
ManufactureData = null;
CrossLocalNotifications.Current.Show("no advertising data", "no advertising data", 10);
central.ScanForPeripherals(cbuuids);
return;
}
central.ScanForPeripherals(cbuuids);
}
catch
{
central.ScanForPeripherals(cbuuids);
}
}
I'm working on an OS X application that displays custom windows on all available spaces of all the connected displays.
I can get an array of the available display objects by calling [NSScreen screens].
What I'm currently missing is a way of telling if the user connects a display to or disconnects a screen from their system.
I have searched the Cocoa documentation for notifications that deal with a scenario like that without much luck, and I refuse to believe that there isn't some sort of system notification that gets posted when changing the number of displays connected to the system.
Any suggestions on how to solve this problem?
There are several ways to achieve that:
You could implement applicationDidChangeScreenParameters: in your app delegate (the method is part of the NSApplicationDelegateProtocol).
Another way is to listen for the NSApplicationDidChangeScreenParametersNotification sent by the default notification center [NSNotificationCenter defaultCenter].
Whenever your delegate method is called or you receive the notification, you can iterate over [NSScreen screens] and see if a display got connected or removed (you have to maintain a display list you can check against at program launch).
A non-Cocoa approach would be via Core Graphics Display services:
You have to implement a reconfiguration function and register it with CGDisplayRegisterReconfigurationCallback(CGDisplayReconfigurationCallBack cb, void* obj);
In your reconfiguration function you can query the state of the affected display. E.g.:
void DisplayReconfigurationCallBack(CGDirectDisplayID display, CGDisplayChangeSummaryFlags flags, void* userInfo)
{
if(display == someDisplayYouAreInterestedIn)
{
if(flags & kCGDisplaySetModeFlag)
{
...
}
if(flags & kCGDisplayRemoveFlag)
{
...
}
if(flags & kCGDisplayDisabledFlag)
{
...
}
}
if(flags & kCGDisplaySetModeFlag || flags & kCGDisplayDisabledFlag || flags & kCGDisplayRemoveFlag)
{
...
}
}
in swift 3.0:
let nc = NotificationCenter.default
nc.addObserver(self,
selector: #selector(screenDidChange),
name: NSNotification.Name.NSApplicationDidChangeScreenParameters,
object: nil)
NC call back:
final func screenDidChange(notification: NSNotification){
let userInfo = notification.userInfo
print(userInfo)
}
I'm playing game sounds using OpenAL, and bg music using standard AV. Recently i've found that after the
incoming call all openal sounds don't work while bg music is still playing. If I force stop app and start again
sounds appear again. Do smbd happen to know what's happening to openal during/after the incoming call?
Ok, it seems I've found a solution.
I'm using obj-c sound manager, so I just added beginInterruption and endInterruption delegate methods of AVAudioSession (and AVAudioPlayer) to my class.
beginInterruption looks like:
alcMakeContextCurrent(NULL);
and endInterruption looks something like:
NSError * audioSessionError = NULL;
[audioSession setCategory:soundCategory error:&audioSessionError];
if (audioSessionError)
{
Log(#"ERROR - SoundManager: Unable to set the audio session category");
return;
}
// Set the audio session state to true and report any errors
audioSessionError = NULL;
[audioSession setActive:YES error:&audioSessionError];
if (audioSessionError)
{
Log(#"ERROR - SoundManager: Unable to set the audio session state to YES with error %d.", (int) result);
return;
}
//music players handling
bool plays = false;
if (musicPlayer[currentPlayer] != nil)
plays = [musicPlayer[currentPlayer] isPlaying];
if (musicPlayer[currentPlayer] != nil && !plays)
[musicPlayer[currentPlayer] play];
alcMakeContextCurrent(context);
Yes, this works if you're using only openAL sounds. But to play long tracks you should use AVAudioPlayer.
But here's the Apple magic again! If you play music along with OpenAL sounds something odd happens.
Cancel the incoming call and AVAudioSessionDelegate::endInterruption with AVAudioPlayerDelegate::audioPlayerEndInterruption will never called. Only beginInterruption, not the end.
Even AppDelegate::applicationWillEnterForeground will not be called, and app just don't know that we've returned.
But the good news is that you can call your endInterruption in AppDelegate::applicationDidBecomeActive method, and openAL context will be restored. And this works!
- (void)applicationDidBecomeActive:(UIApplication *)application
{
if (MySoundMngr != nil)
{
[MySoundMngr endInterruption];
}
// Restart any tasks that were paused and so on....
}
I had a hard time figuring this out so wanted to add my answer here. This is all specifically in Xamarin, but I suspect it applies generally and is similar to #Tertium's answer
You can prevent iOS from interrupting your audio in some situations (e.g., getting a phone call but declining it), using AVAudioSession.SharedInstance().SetPrefersNoInterruptionsFromSystemAlerts(true, out NSError err);
You will still be interrupted in some situations (e.g., you accept a phone call). To catch these you must AVAudioSession.Notifications.ObserveInteruption(myAudioInterruptionHandler); when you launch your app.
Inside this handler, you can determine if you're shutting down or coming back like so:
void myAudioInterruptionHandler(object sender, AVAudioSessionInterruptionEventArgs args) {
args.Notification.UserInfo.TryGetValue(
new NSString("AVAudioSessionInterruptionTypeKey"),
out NSObject typeKey
);
bool isBeginningInterruption = (typeKey.ToString() == "1");
// ...
}
Interruption Begins
When the interruption begins, stop whatever audio is playing (you'll need to handle this on your own based on your app, but probably by calling AL.SourceStop on everything).
Then, critically,
ContextHandle audioContextHandle = Alc.GetCurrentContext();
Alc.MakeContextCurrent(ContextHandle.Zero);
If you don't do this right away, iOS will fry your ALC context and you are doomed. Note that if you have a handler for AudioRouteChanged this is too late, you must do it in the AudioInterruption handler.
Interruption Ends
When you're coming back from the interruption, first reboot your iOS audio session:
AVAudioSession.SharedInstance().SetActive(true);
You may also need to reset your preferred input (I think this step is optional if you always use the default input) AVAudioSession.SharedInstance().SetPreferredInput(Input, out NSError err)
Then restore your context
Alc.MakeContextCurrent(audioContextHandle);
I'm currently developing a camera application for Android on which some problems have occurred. I need it to work on all Android devices and since all of these works in different ways specially with the camera hardware, I'm having a hard time finding a solution that works for every device.
My application main goal is to launch the camera on a button click, take a photo and upload it to a server. So I don't really need the functionality of saving the image on the device, but if that's needed for further image use I might as well allow it.
For example I'm testing my application on a Samsung Galaxy SII and a Motorola Pad. I got working code that launches the camera, which is by the way C# code since I'm using Monodroid:
Intent cameraIntent = new Intent(Android.Provider.MediaStore.ActionImageCapture);
StartActivityForResult(cameraIntent, PHOTO_CAPTURE);
And I fetch the result, similar to this guide I followed:
http://kevinpotgieter.wordpress.com/2011/03/30/null-intent-passed-back-on-samsung-galaxy-tab/
Why I followed this guide is because the activity returns null on my galaxy device (Another device oriented problem).
This code works fine on the Galaxy device. It takes a photo and saves the photo in the gallery from which i can upload to a server. By further research this is apparently galaxy standard behaviour, so this doesn't work on my Motorola pad. The camera works fine, but no image is saved to gallery.
So with this background my question is, am I on the right path here? Do I need to save the image to gallery in order for further use in my application? Is there any solution that works for every Android device, cause that's the solution i need.
Thanks for any feedback!
After reading the linked article, the approach taken in that article is geared toward the Galaxy line, since they appear to write to the gallery automatically.
This article discusses some other scenarios in detail:
Android ACTION_IMAGE_CAPTURE Intent
So, I don't necessarily think that following the linked article that you provided is the right path. Not all devices automatically write to the gallery as described in that article, afaik. The article I linked to points to the issues being related to security and suggests writing the image to a /sdcard/tmp folder for storing the original image. Going down a similar path would more than likely lead to code that is going to work reliably across many devices.
Here are some other links for reference:
Google discussion regarding this subject: http://code.google.com/p/android/issues/detail?id=1480
Project with potential a solution to the problem: https://github.com/johnyma22/classdroid
While that discussion/project are in Java/Android SDK, the same concepts should apply to Monodroid. I'd be happy to help you adapt the code to a working Mono for Android solution if you need help.
To long2know:
Yes the same concepts applies to Monodroid. I've already read the stack article you linked among with some other similar. However i don't like the approach in that particular post since it checks for bugs for some devices that are hardcoded into a collection. Meaning it might fail to detect bugs in future devices. Since i won't be doing maintenance on this application, i can't allow this. I found a solution elsewhere and adapted it to my case and i'll post it below if someone would need it. It works on both my devices, guessing it would work for the majority of other devices. Thanks for your post!
Solution that allows you to snap a picture and use, also with the option of using a image from gallery. Solution uses option menu for these purposes, just for testing. (Monodroid code).
Camera code is inspired by:
access to full resolution pictures from camera with MonoDroid
namespace StackOverFlow.UsingCameraWithMonodroid
{
[Activity(Label = "ImageActivity")]
public class ImageActivity
private readonly static int TakePicture = 1;
private readonly static int SelectPicture = 2;
private string imageUriString;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
this.SetContentView(Resource.Layout.ImageActivity);
}
public override bool OnCreateOptionsMenu(IMenu menu)
{
MenuInflater flate = this.MenuInflater;
flate.Inflate(Resource.Menu.ImageMenues, menu);
return base.OnCreateOptionsMenu(menu);
}
public override bool OnOptionsItemSelected(IMenuItem item)
{
switch (item.ItemId)
{
case Resource.Id.UseExisting:
this.SelectImageFromStorage();
return true;
case Resource.Id.AddNew:
this.StartCamera();
return true;
default:
return base.OnOptionsItemSelected(item);
}
}
private Boolean isMounted
{
get
{
return Android.OS.Environment.ExternalStorageState.Equals(Android.OS.Environment.MediaMounted);
}
}
private void StartCamera()
{
var imageUri = ContentResolver.Insert(isMounted ? MediaStore.Images.Media.ExternalContentUri
: MediaStore.Images.Media.InternalContentUri, new ContentValues());
this.imageUriString = imageUri.ToString();
var cameraIntent = new Intent(MediaStore.ActionImageCapture);
cameraIntent.PutExtra(MediaStore.ExtraOutput, imageUri);
this.StartActivityForResult(cameraIntent, TakePicture);
}
private void SelectImageFromStorage()
{
Intent intent = new Intent();
intent.SetType("image/*");
intent.SetAction(Intent.ActionGetContent);
this.StartActivityForResult(Intent.CreateChooser(intent,
"Select Picture"), SelectPicture);
}
// Example code of using the result, in my case i want to upload in another activity
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
// If a picture was taken
if (resultCode == Result.Ok && requestCode == TakePicture)
{
// For some devices data can become null when using the camera activity.
// For this reason we save pass the already saved imageUriString to the upload activity
// in order to adapt to every device. Instead we would want to use the data intent
// like in the SelectPicture option.
var uploadIntent = new Intent(this.BaseContext, typeof(UploadActivity));
uploadIntent.PutExtra("ImageUri", this.imageUriString);
this.StartActivity(uploadIntent);
}
// User has selected a image from storage
else if (requestCode == SelectPicture)
{
var uploadIntent = new Intent(this.BaseContext, typeof(UploadActivity));
uploadIntent.PutExtra("ImageUri", data.DataString);
this.StartActivity(uploadIntent);
}
}
}
}
My cocoa app runs background tasks, which I would like to stop when the user becomes idle (no keyboard/mouse input) and then resume when the user becomes active again. Is there a way to register for idle-state notifications?
In case you can't link to Carbon (ie. you want to compile x86_64 bit binary) you can wrap this function (which returns current idle time in seconds resolution as double - CFTimeInterval) in a timer:
#include <IOKit/IOKitLib.h>
CFTimeInterval CFDateGetIdleTimeInterval() {
mach_port_t port;
io_iterator_t iter;
CFTypeRef value = kCFNull;
uint64_t idle = 0;
CFMutableDictionaryRef properties = NULL;
io_registry_entry_t entry;
IOMasterPort(MACH_PORT_NULL, &port);
IOServiceGetMatchingServices(port, IOServiceMatching("IOHIDSystem"), &iter);
if (iter) {
if ((entry = IOIteratorNext(iter))) {
if (IORegistryEntryCreateCFProperties(entry, &properties, kCFAllocatorDefault, 0) == KERN_SUCCESS && properties) {
if (CFDictionaryGetValueIfPresent(properties, CFSTR("HIDIdleTime"), &value)) {
if (CFGetTypeID(value) == CFDataGetTypeID()) {
CFDataGetBytes(value, CFRangeMake(0, sizeof(idle)), (UInt8 *) &idle);
} else if (CFGetTypeID(value) == CFNumberGetTypeID()) {
CFNumberGetValue(value, kCFNumberSInt64Type, &idle);
}
}
CFRelease(properties);
}
IOObjectRelease(entry);
}
IOObjectRelease(iter);
}
return idle / 1000000000.0;
}
You'll need to link your code to IOKit.framework
There's a Carbon API that will send a notification when there hasn't been a user event after a certain duration called EventLoopIdleTimer. Uli Kusterer has written a Cocoa wrapper for here (look for UKIdleTimer).
If you want something lower level, you may be able to implement the behavior you want with a combination of timers and the CoreGraphics function CGEventSourceSecondsSinceLastEventType (available in <CoreGraphics/CGEventSource.h>).
Apple's Technical Q&A QA1340 Registering and unregistering for sleep and wake notifications may be what you are looking for.
If you need more control than NSWorkspaceWillSleepNotification (Listing 1), use I/O Kit and register to receive power notifications (Listing 3).
I used a different approach.
Subclassing UIApplication I override the sendEvent method filtering touches (actually you can filter any kind of event, acceleration, touches, etc.).
Using a shared variable and a background timer I managed the "idle".
Every time the user touch the screen the variable is set with current timeInterval (current time).
The timer fire method checks for the elapsed time since last touch, if greater than the threshold (in my case was around 90seconds) you can POST your own notification.
I used this simple approach to create a custom set of apps that after some idle time automatically call the "screensaver" app.
Nothing clever, it just do the job.
Hope that helps.