I would appreciated some help please even if this is maybe a trivial question.
I've written a SwiftUI app that reads the media library from the device and plays it depending on user settings. That is all fine.
The problem I have is that if you install the app for the first time, the user needs to grant permission to access the media library. This appears to be a system generated dialog but I cannot see which step in the also triggers it. I tried to have the access request be triggered code generated but that doesn't seem to trigger the pop up but it still only appears at a later stage in the app load process. The code seems to recognise though that the user reacted to the access request pop up and does select the correct switch case.
What it does not seem to do though is that it still can't read the media library. The MPMediaQuery returns nil.
My suspicion is that it somehow connected to the fact that the access request doesn't run on the main thread but I am not experienced enough in Swift programming to know what the problem is. I would be most grateful for some helpful hints.
Here is my code:
import MediaPlayer
import SwiftUI
import Foundation
class Library {
var artists : [Artist] = []
#EnvironmentObject var settings : UserSettings
var counter : Float = 0
init() {
switch MPMediaLibrary.authorizationStatus() {
case .authorized:
print("authorized")
case .denied:
print("denied")
return
case .notDetermined:
print("not determined")
MPMediaLibrary.requestAuthorization() { granted in
if granted != .authorized {
return
}
}
case .restricted:
print("restricted")
#unknown default:
print("default")
}
if MPMediaLibrary.authorizationStatus() == .notDetermined { return }
let filter : Set<MPMediaPropertyPredicate> = [MPMediaPropertyPredicate(value: MPMediaType.music.rawValue, forProperty: MPMediaItemPropertyMediaType)]
let mediaQuery = MPMediaQuery(filterPredicates: filter )
var artistsInCollection : [Artist] = []
guard let _ = mediaQuery.items?.count else { return }
for item in mediaQuery.items! {
//here I do something but that's not relevant to my question
}
self.artists = artistsInCollection
}
}
I can't find any way to check if a text field exists without trying to get it which then fails the tests and shows an error if it can't be found. No matches found for TextField
Current code
XCUIElement *usernameTextField = app.textFields[#"username"];
Reason/detail
I've got a Objective C UITest in XCode which logs into my app in setUp and logs out in tearDown however sometimes my app is already logged in when the test starts (if the simulator has been used for anything else in the meantime). I'd like to be able to check to see if the username textfield exists in my setUp and then if it doesn't I can skip the login or call my logout function and continue as normal.
Not sure about Obj-C but here's how it would work in Swift.
let usernameTextField = app.textFields["username"]
if usernameTextField.exists {
do something
} else {
do something else
}
Here is the code in Swift, which can easily be converted to Obj-C:
// given:
// usernameTextField exists
// The username that is possibly entered there is "username".
// then:
if usernameTextField.value as! String == "username" {
// logged in
} else {
// not logged in
}
In my OSX application I'm using code below to show preview from camera.
[[self session] beginConfiguration];
NSError *error = nil;
AVCaptureDeviceInput *newVideoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
if (captureDevice != nil) {
[[self session] removeInput: [self videoDeviceInput]];
if([[self session] canAddInput: newVideoDeviceInput]) {
[[self session] addInput:newVideoDeviceInput];
[self setVideoDeviceInput:newVideoDeviceInput];
} else {
DLog(#"WTF?");
}
}
[[self session] commitConfiguration];
Yet, I need to detect the exact time when the preview from the camera becomes available.
In other words I'm trying to detect the same moment like in Facetime under OSX, where animation starts once the camera provides the preview.
What is the best way to achieve this?
I know this question is really old, but I stumbled upon it too when I was looking for this same question, and I have found answers so here goes.
For starters, AVFoundation is too high level, you'll need to drop down to a lower level, CoreMediaIO. There's not a lot of documentation on this, but basically you need to perform a couple queries.
To do this, we'll use a combination of calls. First, CMIOObjectGetPropertyDataSize lets us get the size of the data we'll query for next, which we can then use when we call CMIOObjectGetPropertyData. To set up the get property data size call, we need to start at the top, using this property address:
var opa = CMIOObjectPropertyAddress(
mSelector: CMIOObjectPropertySelector(kCMIOHardwarePropertyDevices),
mScope: CMIOObjectPropertyScope(kCMIOObjectPropertyScopeGlobal),
mElement: CMIOObjectPropertyElement(kCMIOObjectPropertyElementMaster)
)
Next, we'll set up some variables to keep the data we'll need:
var (dataSize, dataUsed) = (UInt32(0), UInt32(0))
var result = CMIOObjectGetPropertyDataSize(CMIOObjectID(kCMIOObjectSystemObject), &opa, 0, nil, &dataSize)
var devices: UnsafeMutableRawPointer? = nil
From this point on, we'll need to wait until we get some data out, so let's busy loop:
repeat {
if devices != nil {
free(devices)
devices = nil
}
devices = malloc(Int(dataSize))
result = CMIOObjectGetPropertyData(CMIOObjectID(kCMIOObjectSystemObject), &opa, 0, nil, dataSize, &dataUsed, devices);
} while result == OSStatus(kCMIOHardwareBadPropertySizeError)
Once we get past this point in our execution, devices will point to potentially many devices. We need to loop through them, somewhat like this:
if let devices = devices {
for offset in stride(from: 0, to: dataSize, by: MemoryLayout<CMIOObjectID>.size) {
let current = devices.advanced(by: Int(offset)).assumingMemoryBound(to: CMIOObjectID.self)
// current.pointee is your object ID you will want to keep track of somehow
}
}
Finally, clean up devices
free(devices)
Now at this point, you'll want to use that object ID you saved above to make another query. We need a new property address:
var CMIOObjectPropertyAddress(
mSelector: CMIOObjectPropertySelector(kCMIODevicePropertyDeviceIsRunningSomewhere),
mScope: CMIOObjectPropertyScope(kCMIOObjectPropertyScopeWildcard),
mElement: CMIOObjectPropertyElement(kCMIOObjectPropertyElementWildcard)
)
This tells CoreMediaIO that we want to know if the device is currently running somewhere (read: in any app), wildcarding the rest of the fields. Next we get to the meat of the query, camera below corresponds to the ID you saved before:
var (dataSize, dataUsed) = (UInt32(0), UInt32(0))
var result = CMIOObjectGetPropertyDataSize(camera, &opa, 0, nil, &dataSize)
if result == OSStatus(kCMIOHardwareNoError) {
if let data = malloc(Int(dataSize)) {
result = CMIOObjectGetPropertyData(camera, &opa, 0, nil, dataSize, &dataUsed, data)
let on = data.assumingMemoryBound(to: UInt8.self)
// on.pointee != 0 means that it's in use somewhere, 0 means not in use anywhere
}
}
With the above code samples you should have enough to test whether or not the camera is in use. You only need to get the device once (the first part of the answer); the check for if it's in use however, you'll have to do at any time you want this information. As an extra exercise, consider playing with CMIOObjectAddPropertyListenerBlock to be notified on event changes for the in use property address we used above.
While this answer is nearly 3 years too late for the OP, I hope it helps someone in the future. Examples here are given with Swift 3.0.
The previous answer from the user jer is definitely the correct answer, but I just wanted to add one additional important information.
If a listener block is registered with CMIOObjectAddPropertyListenerBlock, the current run loop must be run, otherwise no event will be received and the listener block will never fire.
I'm setting up a very basic OSX app for an existing firebase with SimpleLogin and email/password authentication.
Here's the code I'm using.
- (void) applicationDidFinishLaunching:(NSNotification *)notification {
Firebase* ref = [[Firebase alloc] initWithUrl:#"https://myapp.firebaseio.com"];
FirebaseSimpleLogin* authClient = [[FirebaseSimpleLogin alloc] initWithRef:ref];
[authClient loginWithEmail:#"myemail#mydomain.com" andPassword:#"mypassword"
withCompletionBlock:^(NSError* error, FAUser* user) {
if (error != nil) {
// There was an error logging in to this account
NSLog(#"authClient login error: %#", error);
} else {
NSLog(#"Login success.");
}
}];
}
Login is successful, and I see the log output. However, "FAUser* user" is nil. How? Why?
Online search / existing SO questions haven't helped..
Any ideas?
** UPDATE **
Same code in iOS works as expected. Is this just an OSX issue?
** UPDATE 2 **
I compiled the source code from the Firebase/Objective-C Simple Login Service (which seems to only reference iOS) directly in my OSX project and found that there is a "duplicate item" error code when the login service tries to store Keychain data on OSX.
The source code after the keychain save operation then proceeds to return a null user. I believe there is a logic error here because the if statement evaluates to true whenever it is not a success code (skipping the special case for duplicate item):
if (status != noErr) {
user = nil;
}
else if (status == errSecDuplicateItem) {
// TODO: log an error?
user = nil;
}
Anyway, I am able to continue working by modifying this small chunk of code to fit my needs.
Yeah, you're right. It's an error with accessing Keychain.
To clear the error on your own machine, you can go to Keychain Access, search for 'firebase' in the upper right. You should get an item with the name https://auth.firebase.com. Click it. Check that it says Firebase_<YOUR_FIREBASE_NAME> for the Account field, and go ahead and delete it. The next time you spin up your app, you'll have to log in again.
This seems to show up when you try to hit the same keychain item many times at once. Accessing the keychain slowly multiple times seems to be fine, so unless someone is authenticating many of the same app on the same machine, you shouldn't get the error. (If you can hit it some other way, please share!)
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)
}