In the new Elmish.WPF 4.0 beta version, where is runWindowWithConfig? - f#

I've been playing with the new beta version of Elmish.WPF 4.0 and can't seem to find
Program.runWindowWithConfig. Has it been replaced?
let entryPoint (_: string[], mainWindow: Window) =
Program.mkProgram init update bindings
|> Program.runWindowWithConfig
{ ElmConfig.Default with LogTrace = true; Measure = true; MeasureLimitMs = 1 }
mainWindow
TIA

Yes, it has been replaced. I replaced it with a setting function on WpfProgram for each field of the config. This design allows adding a new value to configure in a backwards compatible manner. See a sample.

Related

MvvmCross Xamarin.Forms Modal Dialogs

I'm just trying to make my first app with MvvmCross but I already encounter a problem for my app and can't find anything on the web for that. I want to open a specific page as a modal dialog on supported devices (eg. iPads). For my non MvvmCross applications I do this with Rg.Plugin.Popup but I do not want it this way this time. I found a few solutions on how it can be done with native and MvvmCross but nothing about how it is done with Xamarin.Forms in combination to MvvmCross. Did I need to implement a own presenter and filter on the type of my page (because this page should always be modal on supported devices)? And if I do so, is there any example for this?
Using MvvmCross 5.2.0, the following worked for me (on iOS at least; haven't tested on Android):
var bundle = new MvxBundle(new Dictionary<string, string>{ { MvxFormsPagePresenter.ModalPresentationParameter, "true" } });
await _navService.Navigate<MyViewModel>(bundle);
This uses the stock-standard MvxFormsPagePresenter, so you don't have to create your own presenter.
I'm using MVVMCross 7.1.2 here, this was tested on Android only.
In your Views code behind implement IMvxOverridePresentationAttribute with code similar to this.
public MvxBasePresentationAttribute PresentationAttribute(MvxViewModelRequest request)
{
if (request.PresentationValues == null) return null;
if (request.PresentationValues.ContainsKey("NavigationMode") &&
request.PresentationValues["NavigationMode"] == "Modal")
{
return new MvxModalPresentationAttribute
{
WrapInNavigationPage = true,
Animated = false,
NoHistory = true
};
}
return null;
}
All you need to do now, is when Navigating to the view model is just pass a key value pair as the parameter like this
await NavigationService.Navigate<MainViewModel>(new MvxBundle(new Dictionary<string, string> { { "NavigationMode", "Modal" } }));
That's it... easy as that !

Xamarin forms zxing ZXingScannerView on ios

I am writing a mobile app in xamarin forms and I have half the screen continuously scanning barcodes using ZXingScannerView. This works great in android however in ios it will not pick up any barcodes using ZXingScannerView. However ios does pick up barcodes using the full page ZXingScannerPage. In my example code below the method Scanner_OnScanResult is never getting hit. How can I get this to work in ios am i missing something?
ZXingScannerView scanner = new ZXingScannerView
{
HorizontalOptions = LayoutOptions.FillAndExpand,
VerticalOptions = LayoutOptions.FillAndExpand,
AutomationId = "zxingScannerView",
IsScanning = true,
Options = new ZXing.Mobile.MobileBarcodeScanningOptions
{
UseFrontCameraIfAvailable = false,//update later to come from settings
PossibleFormats = new List<ZXing.BarcodeFormat>(),
TryHarder = true
}
};
ZXingDefaultOverlay overlay = new ZXingDefaultOverlay();
scanner.Options.PossibleFormats.Add(ZXing.BarcodeFormat.QR_CODE);.
scanner.OnScanResult += Scanner_OnScanResult;
private void Scanner_OnScanResult(ZXing.Result result)
{
DisplayAlert("Exit", "TEST", "Yes", "No");
}
I eventually got this working however i'm not sure if its a bug or just inconsistent design but in iOS IsAnalyzing must be set to true manually when working in a view

How do I debug a command-line Dart app that uses async? (breakpoints not working)

The debugger in IntelliJ or the Dart Editor won't stop at the breakpoint for this code:
main() async {
var x = 1;
bool stop = true; // breakpoint here
}
... but does for this code:
main() {
var x = 1;
bool stop = true; // breakpoint here
}
Dart SDK 1.8.3 and latest stable releases on both IDEs.
This is a known issue that is fixed in the dev channel and will be released in the 1.9 stable channel. See Breakpoint set inside of async function does not trigger.

Check if a function is available in Swift?

I would like to detect if the user has enabled Reduce Transparency. It's simple you just call the func UIAccessibilityIsReduceMotionEnabled() and it returns a Bool. But my app targets iOS 7 and 8 and this function isn't available on iOS 7.
In Objective-C, this is how I checked to see if that function exists:
if (UIAccessibilityIsReduceMotionEnabled != NULL) { }
In Swift, I can't figure out how to check if it exists or not. According to this answer, you can simply use optional chaining and if it's nil then it doesn't exist, but that is restricted to Obj-C protocols apparently. Xcode 6.1 doesn't like this:
let reduceMotionDetectionIsAvailable = UIAccessibilityIsReduceMotionEnabled?()
It wants you to remove the ?. And of course if you do so it will crash on iOS 7 because that function doesn't exist.
What is the proper way to check if these types of functions exist?
A proper check for availability has been added in Swift 2. This is recommended over other options mentioned here.
var shouldApplyMotionEffects = true
if #available(iOS 8.0, *) {
shouldApplyMotionEffects = !UIAccessibilityIsReduceMotionEnabled()
}
If you're okay with being a little bit cheeky, you can always open the UIKit binary using the library loader and see if it can resolve the symbol:
let uikitbundle = NSBundle(forClass: UIView.self)
let uikit = dlopen(uikitbundle.executablePath!, RTLD_LAZY)
let handle = dlsym(uikit, "UIAccessibilityIsReduceMotionEnabled")
if handle == nil {
println("Not available!")
} else {
println("Available!")
}
The dlopen and dlsym calls can be kinda expensive though so I would recommend keeping the dlopen handle open for the life of the application and storing somewhere the result of trying to dlsym. If you don't, make sure you dlclose it.
As far as I know this is AppStore safe, since UIAccessibilityIsReduceMotionEnabled is a public API.
You could check to see if you're running in iOS 8 or higher --
var reduceMotionEnabled = false
if NSProcessInfo().isOperatingSystemAtLeastVersion(NSOperatingSystemVersion(majorVersion: 8, minorVersion: 0, patchVersion: 0)) {
reduceMotionEnabled = UIAccessibilityIsReduceMotionEnabled()
}
I don't think there's another way to tell. So in theory, if you were able to check, trying to access the function name without the () would give you nil in iOS 7 and the () -> Bool function in iOS 8. However, in order for that to happen, UIAccessibilityIsReduceMotionEnabled would need to be defined as (() -> Bool)?, which it isn't. Testing it out yields a function instance in both versions of iOS that crashes if called in iOS 7:
let reduceMotionDetectionIsAvailable = UIAccessibilityIsReduceMotionEnabled
// reduceMotionDetectionIsAvailable is now a () -> Bool
reduceMotionDetectionIsAvailable()
// crashes in iOS7, fine in iOS8
The only way I can see to do it without testing the version is simply to define your own C function to check in your bridging header file, and call that:
// ObjC
static inline BOOL reduceMotionDetectionIsAvailable() {
return (UIAccessibilityIsReduceMotionEnabled != NULL);
}
// Swift
var reduceMotionEnabled = false
if reduceMotionDetectionIsAvailable() {
reduceMotionEnabled = UIAccessibilityIsReduceMotionEnabled()
}
From the Apple Developer docs (Using Swift with Cocoa and Objective-C (Swift 3) > Interoperability > Adopting Cocoa Design Patterns > API Availability):
Swift code can use the availability of APIs as a condition at
run-time. Availability checks can be used in place of a condition in a
control flow statement, such as an if, guard, or while
statement.
Taking the previous example, you can check availability in an if
statement to call requestWhenInUseAuthorization() only if the method
is available at runtime:
let locationManager = CLLocationManager()
if #available(iOS 8.0, macOS 10.10, *) {
locationManager.requestWhenInUseAuthorization()
}
Alternatively, you can check availability in a guard statement,
which exits out of scope unless the current target satisfies the
specified requirements. This approach simplifies the logic of handling
different platform capabilities.
let locationManager = CLLocationManager()
guard #available(iOS 8.0, macOS 10.10, *) else { return }
locationManager.requestWhenInUseAuthorization()
Each platform argument consists of one of platform names listed below,
followed by corresponding version number. The last argument is an
asterisk (*), which is used to handle potential future platforms.
Platform Names:
iOS
iOSApplicationExtension
macOS
macOSApplicationExtension
watchOS
watchOSApplicationExtension
tvOS
tvOSApplicationExtension

Xamarin Forms WebView Check When Website Address Changed

I have the following code that sets up a WebView inside my Xamarin.Forms Cross Platform application:
ReportsListWebView = new WebView()
{
VerticalOptions = LayoutOptions.FillAndExpand,
HorizontalOptions = LayoutOptions.FillAndExpand,
BackgroundColor = Xamarin.Forms.Color.Transparent
};
URLReportsListWebView = new UrlWebViewSource
{
Url = "http://192.168.0.96/MyWebsite/App/MiniMyWebsite?ActionType=Listing&Params=Reports"
};
ReportsListWebView.Source = URLReportsListWebView;
grid.Children.Add(ReportsListWebView, 0, 4, 0, 1);
The situation is that there is listing within the website that I am referencing in the WebView. When the user selects an item in the listing on the webpage it has javascript that changes the url of the website (appends #SelectedItem=1 to the url). I just want to be able to recognize this change from within the application.
I've checked the URLReportsListWebView.Url but it doesn't seem to update with the latest changes. Any ideas on how to achieve this?
Thanks
This ended up being a limitation on the xamarin forms webview control. The work around was to create a custom renderer which the Xamarin support provided me a great same showing how to accomplish this at github.com/jgold6/XFormsWebViewCustomRenderer/tree/master
When I've done a few tests against http://www.yahoo.com it appears to be updating the WebView.Source property ok, even with query string attribues.
Are you just updating the location of the current webpage rather than navigating to a new page?
Maybe this could be the reason why its not working for you?
If so, after the change, you will then be able to monitor the .Source property for the newly navigated webpage as there is no event handler or anything to hook into to get notified when a page has been navigated to / fully loaded.
Update 1:-
Try the following that is working for me.
It should produce updates similar to the following:-
http://www.yahoo.com
https://fr.yahoo.com/?p=us
https://fr.news.yahoo.com/syrie-jihadistes-exécutent-160-soldats-43-casques-bleus-050134941.html
http://www.tv3g.bouquettv.mobi/wap/landing/landing2.asp?c=LFYAH_TVGREEN_AAAMMM&IDLanding=16972&tag=0&Alea=7.906741E-02&Al=MM201408290946299694
Code:-
StackLayout objStackLayout = new StackLayout()
{
};
//
WebView objWebView1 = new WebView();
objWebView1.HeightRequest = 300;
objStackLayout.Children.Add(objWebView1);
//
UrlWebViewSource objUrlToNavigateTo = new UrlWebViewSource()
{
Url = "http://www.yahoo.com"
};
objWebView1.Source = objUrlToNavigateTo;
//
//
Button cmdButton1 = new Button();
cmdButton1.Text = "Show Me Current Url";
objStackLayout.Children.Add(cmdButton1);
//
cmdButton1.Clicked += ((o2, e2) =>
{
System.Diagnostics.Debug.WriteLine((objWebView1.Source as UrlWebViewSource).Url);
});
//
//
this.Content = objStackLayout;
If you don't yet have a custom renderer, you'll need to refer to Xamarin documentation to learn how to custom render Xamarin.Forms WebView.
If you already have the custom renderer, inside the CustomRenderer object, you should access the NativeWebview object and assign HandleShouldStartLoad to its ShouldStartLoad event handler. My mistake was that I assigned HandleShouldStartLoad to the event handler of the renderer itself, which won't work.

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