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The following code is shown on apples documentation page for SwiftUI MagnificationGesture:
struct MagnificationGestureView: View {
@GestureState var magnifyBy = CGFloat(1.0)
var magnification: some Gesture {
MagnificationGesture()
.updating($magnifyBy) { currentState, gestureState, transaction in
gestureState = currentState
}
}
var body: some View {
Circle()
.frame(width: 100 * magnifyBy,
height: 100 * magnifyBy,
alignment: .center)
.gesture(magnification)
}
}
Try it (on device) in the Swift Playgrounds App by prepending
import SwiftUI
import PlaygroundSupport
PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.setLiveView(MagnificationGestureView())
or as a compiled app using the app template in Xcode and try to scale the circle to different sizes in succession.
On iPadOS 14 everything works as expected, but since iPadOS 15 Beta 2 it hangs after a few movements of the fingers.
Does it work for you?
What am I doing wrong? I already filed feedback, but the problem remains till the current beta version and I don't know how to get the gestures working again?
Create a new App project in Playgrounds 4 and paste the following code into a new swift file or inside the MyApp file:
import CoreBluetooth
class BTDelegate:NSObject, CBPeripheralDelegate{
public func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor descriptor: CBDescriptor, error: Error?){
}
public func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?){
}
}
This causes the following error to appear:
Method 'preview__peripheral(:didUpdateValueFor:error:)' withObjective-C selector '_preview__peripheral:didUpdateValueFor:error:' conflicts with previous declaration with the same Objective-C selector
Obviously some Playgrounds preview magic can't handle methods with the same name, but different type signature.
Unfortunately I can't rename the methods because they are part of the CBPeripheralDelegate protocol.
Does anyone know a way to solve this problem?
Post not yet marked as solved
Hi,
I tried to create a swift package using xCode's „Swift Package“ template and tried to write some tests.
Unfortunately because my package is all about Bluetooth, the test binary fails with the following message;
xctest[9145:288236] [access] This app has crashed because it attempted to access privacy-sensitive data without a usage description. The app's Info.plist must contain an NSBluetoothAlwaysUsageDescription key with a string value explaining to the user how the app uses this data.
But how to add this key in a Swift Package?
Is it really impossible to write and run test cases for a Swift Package containing Bluetooth? I must miss something...
Post not yet marked as solved
I'm using Swift Playgrounds 4 to develop a test app containing some network code. Unfortunately Playgrounds runs the whole app code multiple times, at least two times: Once for the preview and once when you press "play".
This causes multiple instances of the network code to be running and makes testing very hard.
Is there a way to check if the code is running in preview?
Unfortunately the usual suggested solution using ProcessInfo.processInfo.environment["XCODE_RUNNING_FOR_PREVIEWS"] does not work, because this results in "1" in both cases.
Post not yet marked as solved
I have enabled runtime concurrency warnings to check for future problems concerning concurrency: Build Setting / Other Swift Flags:
-Xfrontend -warn-concurrency -Xfrontend -enable-actor-data-race-checks
When trying to call the async form of PHPhotoLibrary.shared().performChanges{} I get the following runtime warning: warning: data race detected: @MainActor function at ... was not called on the main thread in the line containing performChanges.
My sample code inside a default Xcode multi platform app template is as follows:
import SwiftUI
import Photos
@MainActor
class FotoChanger{
func addFotos() async throws{
await PHPhotoLibrary.requestAuthorization(for: .addOnly)
try! await PHPhotoLibrary.shared().performChanges{
let data = NSDataAsset(name: "Swift")!.data
let creationRequest = PHAssetCreationRequest.forAsset()
creationRequest.addResource(with: .photo, data: data, options: PHAssetResourceCreationOptions())
}
}
}
struct ContentView: View {
var body: some View {
ProgressView()
.task{
try! await FotoChanger().addFotos()
}
}
}
You would have to have a Swift data asset inside the asset catalog to run the above code, but the error can even be recreated if the data is invalid.
But what am I doing wrong? I have not found a way to run perform changes, the block or whatever causes the error on the main thread.
PS: This is only test code to show the problem, don't mind the forced unwraps.
The Archive Framework implements compression algorithms and supports for example the LZMA compression format.
Unfortunately I was not able to find a way to generate a ZIP-kompatible archive using the Archive Framework though iOS / iPadOS seems to be able to do that, because the Files app and the Shortcuts app support this kind of compression.
Is there a way on iOS/iPadOS to generate an LZMA compressed archive with ZIP container using only apple provided APIs or other system services?
PS: I don't need full support for all possible ZIP features. I only need to create a simple archive containing some files which can be opened using any zip decompression program.
https://developer.apple.com/documentation/accelerate/compressing_file_system_directories
Post not yet marked as solved
Hi,is there any way to detect if a key was pressed in SwiftUI on iOS?.onCommand does only exist for macOSand I even tried subclassing UIHostingController to redefine the keyCommands-property but even that did not work.Any way to handly keyboard input in SwiftUI appart from TextField?
Dirk-FU.