I have an XPC service that is using Metal to perform some basic blit operations between textures. I'd like to debug this using Xcode's GPU Frame Capture support but I can't find a way to target my XPC service for capture. I appear to only be able to target the host application.
If I launch my app and XPC service outside of Xcode and then attach to the service using Xcode's debugger, the button to initiate a GPU frame capture is not present.
Is there anyway to debug Metal textures within an XPC service? Even using Xcode's built-in QuickLook support for textures in an XPC service only yields a basic pop-up with addressing info for me.
Related
I have a Xamarin Forms app running in AVAudioSessionCategory = Playback mode and it works very nice, background audio is playing and even my timers keep running in the background, which is fine during playback.
How can I ensure that after a user has decided to stop playing audio (either by pressing a button inside of the app or by pressing the pause button on the lock screen) my app will go into a Suspended state and it won't drain the battery?
Is there a way to either force my app to go suspended or a way to verify whether it has?
As a side-note: Hooking the OnSleep method in App.xaml.cs is NOT sufficient because it is being called every time the app goes to the background even if it's playing audio, my timers are running, HTTP calls working, etc.
UPDATE:
Made an interesting discovery today:
Timers keep running running in the background when the app is started from Visual Studio in debug mode (over WiFi).
Timers seem to get suspended automatically by the OS (iOS) when the app enters background in Release mode.
My conclusion is: maybe the entire problem lies somewhere in the 'framework' that is added to the app by Xamarin to ensure communication between Visual Studio and the app? (Console, breakpoints, etc.) It would be a logical explanation.
I know iOS allows background tasks to run and, for example, continue to receive location updates, but is it possible to do this in a watch app?
In Xcode 9.3, I have configured my app for "background modes" and selected location, and that has created for the WatchKitExtension's an Info.plist, an entry for "Required background modes" of "App registers for location updates".
But my watch app still suspends when the screen turns off, and when it is in the dock.
The App Programming Guide for watchOS, however seems to exclude the possibility of running in the background to receive location updates as it only allows background processing for four classes of activity:
Background App Refresh Tasks. Use a WKApplicationRefreshBackgroundTask object to ...
Background Snapshot Refresh Tasks. Use a WKSnapshotRefreshBackgroundTask object to update ...
Background Watch Connectivity Tasks. Use a WKWatchConnectivityRefreshBackgroundTask object to receive data sent by your iOS app ...
Background NSURLSession Tasks. ...
Other posts to SO indicate it's not possible, but proving a negative is difficult, so I'm asking again:
Am I "flogging a dead horse" by trying to keep the watch App operating in the background for receiving location updates, or is Xcode is making promises that WatchOS won't deliver.
I'm delighted to be able to report that the horse I have been flogging for the past two weeks was not dead after all!
I have discovered an additional state in which my watch app will continue to run in the Background which does not require HKWorkoutSession.
These settings did the trick:
locationManager.allowsBackgroundLocationUpdates = true
and in watchKitExtension info.plist:
set UIBackgroundModes (Required background modes) to location (App registers for location updates)
And I repeat: I am NOT using healthKit
Now my app continues to run even when the screen is off and when the app is out of the Dock.
No, it is not possible.
As the WatchKit Programming Guide clearly states, WatchKit apps cannot use background execution except for 3 use cases:
Network operations using URLSession
Playing audio using WKAudioFilePlayer or WKAudioFileQueuePlayer
Run a workout using HKWorkoutSession
You cannot receive location updates in the background, according to the WatchKit Programming Guide, that should be done in the iOS app that is connected to your watchOS application.
This will be OS dependant so here goes:
Windows 7/8/10
I'd like to be able to access a desktop application UI from another application (that I've written).
I'd like to be able to simply pass some mouse and keyboard inputs from my application to the external one.
Is this possible and if so, where do I start? Is there some Windows API that I can do this with?
I know I can use the Microsoft detours API to hook into Direct3D applications/games, but not sure about regular desktop applications.
I have an app that needs to perform some actions based on a TTimer.
When the app becomes inactive (in background), the timer stops working.
I could not find any relevant options for UIBackgroundModes.
How can I make a timer keeps running?
iOS pauses your app automatically shortly after it goes into the background. You need to let iOS know that you are going to continue operating in the background.
In Project > Options > Version Info you can add to the array key UIBackgroundModes the string values for the services that require to continue running in the background. This gets added to the info.plist for your project on iOS.
You can consult Apple's documentation on what these values do . . .
Value - Description
audio - The app plays audible content in the
background.
location - The app provides location-based information to
the user and requires the use of the standard location services (as
opposed to the significant change location service) to implement this
feature.
voip - The app provides Voice-over-IP services. Apps with this
key are automatically launched after system boot so that the app can
reestablish VoIP services. Apps with this key are also allowed to
play background audio.
fetch - The app requires new content from the
network on a regular basis. When it is convenient to do so, the
system launches or resumes the app in the background and gives it a
small amount of time to download any new content. This value is
supported in iOS 7.0 and later.
remote-notification - The app uses
remote notifications as a signal that there is new content available
for download. When a remote notification arrives, the system launches
or resumes the app in the background and gives it a small amount of
time to download the new content. This value is supported in iOS 7.0
and later.
newsstand-content - The app processes content that was
recently downloaded in the background using the Newsstand Kit
framework, so that the content is ready when the user wants it. This
value is supported in iOS 5.0 and later.
external-accessory - The app
communicates with an accessory that delivers data at regular
intervals. This value is supported in iOS 5.0 and later.
bluetooth-central - The app uses the CoreBluetooth framework to
communicate with a Bluetooth accessory while in the background. This
value is supported in iOS 5.0 and later.
bluetooth-peripheral - The app
uses the CoreBluetooth framework to communicate in peripheral mode
with a Bluetooth accessory. The system will alert the user to the
potential privacy implications of apps with this key set. See Best
Practices for Maintaining User Privacy for more information on
privacy. This value is supported in iOS 6.0 and later.
Notice you need to actually select the mode that matches what you are doing. You can't just select fetch when really all you are doing is background processing.
Basically, I'm looking for any way to go about this at all, no matter how cumbersome or unintuitive, so long as it can be done on iOS 7 (which the third party SBSettings framework currently cannot), and can be done on a non-jailbroken device.
This is for an app which will be loaded into iPads in a physical enclosure so the power button is inaccessible. The device itself will be in single app mode, which cannot be enabled or disabled except through our network-accessed MDM solution. The issue I'm trying to find a way around is that every now and then, the network connection stops functioning and the only way to re-establish it is to restart the device, which can't be done without an internet connection other than to physically press the inaccessible buttons. The reboot action would be password-locked in a hidden event handler and so inaccessible to normal users. This is not an app that will ever see the app store, so Apple's user interface guidelines don't necessarily apply.
Alternatively, is there any way to enable/disable assistive touch programmatically or any other possible method that will enable rebooting the device while in single app mode without physically touching the power button?
This is not a real answer (just thinking aloud).
Obviously, you can't do this through public API.
I believe, API's like SBReset can't do this either, because they are protected by entitlement.
I believe your simplest option to find some reasonably low level API which crashes and use it to crash a device.
I had exactly the same question some time ago:A way to reboot iOS device or restart Springboard using private API?
P.S. I don't have a way to find these crashes. I would recommnd to talk to jailbreak community (people who come up with jailbreaks for iOS devices). They collect all kinds of crashes. Most of these crashes aren't exploitable. However, you don't need an exploit, you just need a OS crash.