I use the following codes for printing in the app:
init() {
self.printInfo.outputType = UIPrintInfoOutputType.photo
self.printInfo.orientation = UIPrintInfoOrientation.landscape
self.printController.printInfo = self.printInfo
self.printer = UIPrinter(url: URL(string: printIP)!)
// where printIP is a string that give the internal IP of the printer
debugPrint(printIP)
}
func print(image: UIImage) -> Bool {
self.printController.printingItem = image
printController.print(to: printer, completionHandler: {(controller, success, error) -> Void in
if success {
debugPrint("Printing Completed.")
} else {
debugPrint("Printing Failed.")
}
})
return true
}
It can print successfully. However, when the function is triggered, there is an alert box indicating that it is contacting to the Printer, and printing. Is there any method to avoid the pop up of this alert box? I want the printing done at the back without showing anything on the screen that interfere the user experience (I want to play a movie when the printer is working at the back).
Thanks.
From iOS 8 there is a way to print without any presentation of the
printing UI. Instead of presenting the UI each time the user presses a
print button, you can provide a way for your users to select a printer
somewhere in your app with the easy-to-use UIPrinterPickerController.
It accepts an optional UIPrinter instance in its constructor for a
pre-selection, uses the same presentation options as explained above,
and has a completion handler for when the user has selected her
printer:
Swift 3
let printerPicker = UIPrinterPickerController(initiallySelectedPrinter: savedPrinter)
printerPicker.present(animated: true) {
(printerPicker, userDidSelect, error) in
if userDidSelect {
self.savedPrinter = printerPicker.selectedPrinter
}
}
Now you can tell your UIPrintInteractionController to print directly by calling printToPrinter(:completionHandler:) with the saved printer instead of using one of the present... methods.
Source:- http://nshipster.com/uiprintinteractioncontroller/
Related
I have weather app. It fetches the data from API. I enter needed city, then next screen opens and shows me the name of the city and temperature. I am writing UI test, which should open the app, handle an alert which asks to use location, then test should write the city name and check if this city exists in the screen. All works except checking the city name at the end. I thought maybe the problem is because it needs some time to get the answer from API, and tests doesn’t wait for it. Maybe I need to set timer to wait for answer. Or the problem is in smth else?
Here is my code and it fails at the last line.
func testExample() throws {
let app = XCUIApplication()
app.launchArguments = ["enable-testing"]
app.launch()
app/*#START_MENU_TOKEN#*/.staticTexts["My location"]/*[[".buttons[\"My location\"].staticTexts[\"My location\"]",".staticTexts[\"My location\"]"],[[[-1,1],[-1,0]]],[0]]#END_MENU_TOKEN#*/.tap()
addUIInterruptionMonitor(withDescription: "Allow “APP” to access your location?") { (alert) -> Bool in
let button = alert.buttons["Only While Using the App"]
if button.exists {
button.tap()
return true // The alert was handled
}
return false // The alert was not handled
}
app.textFields["Enter your city"].tap()
app.textFields["Enter your city"].typeText("Barcelona")
app.buttons["Check weather"].tap()
XCTAssertTrue(app.staticTexts["Barcelona"].exists)
}
XCTest comes with a built-in function you need
Documentation: https://developer.apple.com/documentation/xctest/xcuielement/2879412-waitforexistence/
Example:
XCTAssertTrue(myButton.waitForExistence(timeout: 3), "Button did not appear")
I found the function and used it to wait before the result.
Here is the function and its usage in my code.
func waitForElementToAppear(_ element: XCUIElement) -> Bool {
let predicate = NSPredicate(format: "exists == true")
let expectation = expectation(for: predicate, evaluatedWith: element,
handler: nil)
let result = XCTWaiter().wait(for: [expectation], timeout: 5)
return result == .completed
}
app.textFields["Enter your city"].tap()
app.textFields["Enter your city"].typeText("Barcelona")
app.buttons["Check weather"].tap()
let result = app.staticTexts["Barcelona"]
waitForElementToAppear(result)
XCTAssertTrue(result.exists)
I'm developing a photo editing extension for iOS, bundled in a container app that provides the same photo editing functionality.
In order to reuse code, I have a view controller class that adopts the required PHContentEditingController protocol, and I subclassed it for use both as the main interface of the app extension, and as the "working screen" of the container app.
On the editing extension, the controller's methods are called by the Photos app's editing session as described in Apple's documentation and various tutorials you can find around the web.
On the container app, on the other hand, I first obtain a PHAsset instance by means of the UIImagePickerController class, and directly start the editing session manually on my "work" view controller like this:
// 'work' is my view controller which adopts
// `PHContentEditingController`. 'workNavigation'
// embeds it.
let options = PHContentEditingInputRequestOptions()
options.canHandleAdjustmentData = { (adjustmentData) in
return work.canHandle(adjustmentData)
}
asset.requestContentEditingInput(with: options, completionHandler: { [weak self] (input, options) in
// (Called on the Main thread on iOS 10.0 and above)
guard let this = self else {
return
}
guard let editingInput = input else {
return
}
work.asset = asset
work.startContentEditing(with: editingInput, placeholderImage: editingInput.displaySizeImage!)
this.present(workNavigation, animated: true, completion: nil)
})
When the user finishes editing, the work view controller calls finishContentEditing(completionHandler: on itself to finish the session:
self.finishContentEditing(completionHandler: {(output) in
// nil output results in "Revert" prompt.
// non-nil output results in "Modify" prompt.
let library = PHPhotoLibrary.shared()
library.performChanges({
let request = PHAssetChangeRequest(for: self.asset)
request.contentEditingOutput = output
}, completionHandler: {(didSave, error) in
if let error = error {
// handle error...
} else if didSave {
// proceed after saving...
} else {
// proceed after cancellation...
}
})
})
Within the editing session, the user can 'clear' the previous edits passed as adjustment data, effectively reverting the image to its original state.
I've noticed that, if I finish the editing by calling the completion handler passed to finishContentEditing(completionHandler:) with nil as its argument (instead of a valid PHContentEditingOutput object), the Photos framework will prompt the user to "revert" the image instead of "modifying" it:
func finishContentEditing(completionHandler: #escaping (PHContentEditingOutput?) -> Void) {
guard let editingInput = self.editingInput, let inputURL = editingInput.fullSizeImageURL else {
return completionHandler(nil)
}
if editingInput.adjustmentData != nil && hasUnsavedEdits == false {
// We began with non-nil adjustment data but now have
// no outstanding edits - means REVERT:
return completionHandler(nil)
}
// (...proceed with writing output to url...)
However, this only works when running from the container app. If I try the same trick from the extension (i.e., load an image that contains previous edits, reset them, and tap 'Done') I get the dreaded "Unable to Save Changes" message...
What is the correct way to revert previous edits to an image from within a photo editing extension?
Months later, still no answer, so I begrudgingly adopted this workaround (which is still preferable to an error alert):
When the user taps "Done" from the Photos extension UI and the image has no edits applied to it (either because the user reset previous edits, or didn't apply any changes to a brand new image), perform the following actions from within finishContentEditing(completionHandler:):
Create adjustment data that amounts to no visible changes at all ("null effect") and archive it as Data.
Create a PHAdjustmentData instance with the "null effect" data from above, with the formatVersion and formatIdentifier properly set.
Create a PHContentEditingOutput instance from the editing input passed at the beginning of the session (as usual), and set the adjustment data created above.
Read the unmodified image from the inputURL property of the editing input, and write it unmodified to the url specified by the PHContentEditingOutput instance's renderedContentURL property.
Call the completionHandler block, passing the editing output instance (as normal).
The result: The image is saved in its original state (no effects applied), and no alerts or errors occur.
The drawback: The library asset remains in the 'edited' state (because we passed non-nil editing output and adjustment data, there was no other choice), so the next time the user tries to edit it from Photos.app, the red 'Revert' button will be present:
However, choosing 'revert' results in no visible changes to the image data (duh!), which can be confusing to the user.
—-
Update
I checked what the built-in “Markup” extension does:
...and it is consistent with my workaround above, so I guess this is the best that can be done.
I have been working on an enterprise iOS/Swift (iOS 11.3, Xcode 9.3.1) app in which I want to be notified if the screen changes (goes blank or becomes active) and capture the events in a Realm databse. I am using the answer from tbaranes in detect screen unlock events in IOS Swift and it works, but I find added repeats as the screen goes blank and becomes active:
Initial Blank: a single event recorded
Initial Re-activiation: two events are recorded
Second Blank: two events are recorded
Second Re-act: three events are recorded
and this cycle of adding an additional event recording each cycle.
This must be something in the code (or missing from the code) that is causing an additive effect but I can’t find it. And, yes, the print statements show the issue is not within the Realm database, but are actual repeated statements.
My code is below. Any suggestions are appreciated.
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(), //center
Unmanaged.passUnretained(self).toOpaque(), // observer
displayStatusChangedCallback, // callback
"com.apple.springboard.hasBlankedScreen" as CFString, // event name
nil, // object
.deliverImmediately)
}
private let displayStatusChangedCallback: CFNotificationCallback = { _, cfObserver, cfName, _, _ in
guard let lockState = cfName?.rawValue as String? else {
return
}
let catcher = Unmanaged<AppDelegate>.fromOpaque(UnsafeRawPointer(OpaquePointer(cfObserver)!)).takeUnretainedValue()
catcher.displayStatusChanged(lockState)
print("how many times?")
}
private func displayStatusChanged(_ lockState: String) {
// the "com.apple.springboard.lockcomplete" notification will always come after the "com.apple.springboard.lockstate" notification
print("Darwin notification NAME = \(lockState)")
if lockState == "com.apple.springboard.hasBlankedScreen" {
print("A single Blank Screen")
let statusString = dbSource() // Realm database
statusString.infoString = "blanked screen"
print("statusString: \(statusString)")
statusString.save()
return
}
I am using iOs default PrinterToPrint in Xamarin to print without showing dialog to choose printer but then also it's showing one dialog which says printing to [PRINTER NAME]. Is there anyway to hide the dialog as well. Like complete silent print functionality?
I am not its possible but I have seen some apps which do that and I am not sure whether they are using the same function or not.
Thanks in advance.
Update:
UIPrinterPickerController comes from UIKit and as such there is no way to push the "printing" process to the background and off the main UI thread.
In the current UIPrintInteractionController.PrintToPrinter implementation (currently up to iOS 10.3 B4) there is no exposed way to disable the print progress (Connecting, Preparing, etc...) alart/dialog (w/ Cancel button) or to modify its appearance.
This interface is high level wrapper using AirPrint and thus Internet Print Protocol (IPP) at a lower level to preform the actual printing, job queue monitoring on the printer, etc... IPP is not currently exposed as a publicly available framework within iOS...
Programs that allow background printing are not using UIPrintInteractionController to do the printing. Most do use UIPrinterPickerController to obtain a UIPrinter selection from the user, but then use the UIPrinter.Url.AbsoluteUrl to "talk" directly to the printer via HTTP/HTTPS Post/Get. Depending upon the printers used, TCP-based sockets are also an option vs. IPP and even USB/serial for direct connected printers.
Re: https://en.wikipedia.org/wiki/Internet_Printing_Protocol
Original:
Pick a Printer:
if (allowUserToSelectDifferentPrinter || printerUrl == null)
{
UIPrinter uiPrinter = printerUrl != null ? null as UIPrinter : UIPrinter.FromUrl(new NSUrl(printerUrl));
var uiPrinterPickerController = UIPrinterPickerController.FromPrinter(uiPrinter);
uiPrinterPickerController.Present(true, (printerPickerController, userDidSelect, error) =>
{
if (userDidSelect)
{
uiPrinter = uiPrinterPickerController?.SelectedPrinter;
printerUrl = uiPrinter.Url.AbsoluteUrl.ToString();
Console.WriteLine($"Save this UIPrinter's Url string for later use: {printerUrl}");
}
});
}
Print using UIPrintInteractionController with an existing UIPrinter:
if (printerUrl != null)
{
// re-create a UIPrinter from a saved NSUrl string
var uiPrinter = UIPrinter.FromUrl(new NSUrl(printerUrl));
var printer = UIPrintInteractionController.SharedPrintController;
printer.ShowsPageRange = false;
printer.ShowsNumberOfCopies = false;
printer.ShowsPaperSelectionForLoadedPapers = false;
var printInfo = UIPrintInfo.PrintInfo;
printInfo.OutputType = UIPrintInfoOutputType.General;
printInfo.JobName = "StackOverflow Print Job";
var textFormatter = new UISimpleTextPrintFormatter("StackOverflow Rocks")
{
StartPage = 0,
ContentInsets = new UIEdgeInsets(72, 72, 72, 72),
MaximumContentWidth = 6 * 72,
};
printer.Delegate = new PrintInteractionControllerDelegate();
printer.PrintFormatter = textFormatter;
printer.PrintToPrinter(uiPrinter, (printInteractionController, completed, error) =>
{
if ((completed && error != null))
{
Console.WriteLine($"Print Error: {error.Code}:{error.Description}");
PresentViewController(
UIAlertController.Create("Print Error", "Code: {error.Code} Description: {error.Description}", UIAlertControllerStyle.ActionSheet),
true, () => { });
}
printInfo?.Dispose();
uiPrinter?.Dispose();
uiPrinter.
});
}
else
{
Console.WriteLine("User has not selected a printer...printing disabled");
}
I know this is a somewhat old thread but I had been struggling with implementing a silent printing in iOS for one of my customers and I finally came across an acceptable solution that is very easy to implement.
As mentioned in the accepted answer there is no way to get rid of the popup that displays printing progress. Yet there is a way of hiding it. You can simply change the UIWindowLevel of your key window to UIWindowLevel.Alert + 100. This will guarantee your current window will display above ANY alert view.
Be careful though, as I mentioned, it will be displayed over ANY alert view after the level has been changed. Luckily you can just switch this level back to "Normal" to get the original behavior.
So to recap my solution. I use UIPrintInteractionController.PrintToPrinter in order to print directly to a printer object I created using UIPrinter.FromUrl (this is Xamarin.iOS code btw). Before doing so, I adjust my window level to alert + 100 and once printing is complete I reset my window level to "Normal". Now my printing happens without any visual feedback to my user.
Hope this helps somebody!
I'm using a button to populate a UIPickerView on a hidden UIVisualEffectView. The user clicks the button, the VisualEffectView blurs everything else, and the PickerView displays all the names in their contact list (I'm using SwiftAddressBook to do this.)
This works fine except when the user clicks the button, the UI locks up for about 5-10 seconds. I can't find any evidence of heavy CPU or memory usage. If I just print the sorted array to the console, it happens almost immediately. So something about showing the window is causing this bug.
#IBAction func getBffContacts(sender: AnyObject) {
swiftAddressBook?.requestAccessWithCompletion({ (success, error) -> Void in
if success {
if let people = swiftAddressBook?.allPeople {
self.pickerDataSource = [String]()
for person in people {
if (person.firstName != nil && person.lastName != nil) {
//println("\(person.firstName!) \(person.lastName!)")
self.pickerDataSource.append(person.firstName!)
}
}
//println(self.pickerDataSource)
println("done")
self.sortedNames = self.pickerDataSource.sorted { $0.localizedCaseInsensitiveCompare($1) == NSComparisonResult.OrderedAscending }
self.pickerView.reloadAllComponents()
self.blurView.hidden = false
}
}
else {
//no success, access denied. Optionally evaluate error
}
})
}
You have a threading issue. Read. The. Docs!
requestAccessWithCompletion is merely a wrapper for ABAddressBookRequestAccessWithCompletion. And what do we find there?
The completion handler is called on an arbitrary queue
So your code is running in the background. And you must never, never, never attempt to interact with the user interface on a background thread. All of your code is wrong. You need to step out to the main thread immediately at the start of the completion handler. If you don't, disaster awaits.