MakeTextWritingDirectionRightToLeft(null) in xamarin iOS - xamarin

I'm trying to achieve RightToLeft direction in my project. Other things working fine but label isn't moving to right in iOS for that purpose I have created a LabelRenderer in which I'm passing this method MakeTextWritingDirectionRightToLeft(null) but I'm getting exception
Objective-C exception thrown. Name: NSInvalidArgumentException Reason: -[UILabel makeTextWritingDirectionRightToLeft:]: unrecognized selector sent to instance 0x7fd2fb68b680
Can anyone tell me what to pass in the parameter of this function instead of null?

You can try to use following code to achieve RightToLeft direction in my project.
[assembly: ExportRenderer(typeof(Label), typeof(CustomLabel))]
public class CustomLabel: LabelRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
{
base.OnElementChanged(e);
Control.TextAlignment = UITextAlignment.Right;
}
}

Related

Resolution failed exception in Xamarin IOS prism

I have an iOS application written in Xamarin and I am getting a Unity Exceptions Resolution Failed exception when I try and run the application in iOS. However this error does not happen when I run the android version of the application. The exception is being thrown while the initalize function from prism is taking place.
Here is a snippet from my app.xaml.cs
protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
this.RegisterLocal(containerRegistry);
this.RegisterServices(containerRegistry);
this.RegisterPagesForNavigation(containerRegistry);
}
This code all executes and passes.
This is the iOS initialization
Register("AppDelegate")]
public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate
{
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
global::Xamarin.Forms.Forms.Init();
PullToRefreshLayoutRenderer.Init();
LoadApplication(new App(new IosInitializer()));
return base.FinishedLaunching(app, options);
}
public class IosInitializer : IPlatformInitializer
{
public void RegisterTypes(IContainerRegistry containerRegistry)
{
containerRegistry.Register<IUAirshipUpdate, UAirshipUpdate>();
}
}
This code also executes
The exception being thrown is an argument null exception indicating that IModuleCatelog is not present. I do not understand why it is looking for that module and can not find it. The source code on GitHub indicates that class was registered.
This issue was caused because linker behavior for IOS application was set to full and that causes issues with Unity IOC Container.

RegionManager not injecting properly

I'm trying to pass our application that was using the old Prism 4.0 to latest Prism 7.1.0.431
I'm almost done, everything compiles. Dependency injection has been updated to use latest Unity. So everything seems back on track as I see injection working somewhat.
Though I still have a problem with Module loading: region manager cannot be resolved. I think I'm missing something in my initialization code but cannot find any relevant documentation on that. Try to get into all Prism.Wpf samples but could find relevant code.
Injecting the region manager within module is probably not a good practice from the code I'm seeing while search an answer to my issue, but bear with me that right now it's a huge application and would want to avoid changing that as much as possible:
Here is the exception error I'm having:
EXCEPTION: Prism.Modularity.ModuleInitializeException: An exception occurred while initializing module 'AdvancedExportModule'.
- The exception message was: Resolution of the dependency failed, type = 'Codex.Modules.AdvancedExport.AdvancedExportModule', name = '(none)'.
Exception occurred while: while resolving.
Exception is: InvalidOperationException - The current type, Prism.Regions.IRegionManager, is an interface and cannot be constructed. Are you missing a type mapping?
Am I missing something initialization code for the RegionManager to be mapped and injected correctly by Unity?
Here are the code sample, I tried to simply the most of it and hopefully it's enough for you to understand what's wrong...
This my App.xaml:
<prism:PrismApplication x:Class="Codex.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:prism="http://prismlibrary.com/">
<Application.Resources>
<ResourceDictionary Source="Resources/Merged.xaml"/>
</Application.Resources>
</prism:PrismApplication>
And in my Code behind App.xaml.cs
namespace MyNamespace
{
using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Threading;
using Prism.Ioc;
using Prism.Logging;
using Prism.Modularity;
using Prism.Unity;
public partial class App : PrismApplication
{
private static ILoggerFacade Logger { get; set; }
public static void Main()
{
var application = new App();
application.InitializeComponent();
application.Run();
}
protected override void OnStartup(StartupEventArgs startupEventArgs)
{
base.OnStartup(startupEventArgs);
}
protected override void ConfigureModuleCatalog(IModuleCatalog moduleCatalog)
{
var modulesFilePaths = new Dictionary<string, string>();
modulesFilePaths.Add("Namespace.Modules.Module1.dll", "Namespace.Modules.AdvancedExport.Module1Module");
var pathToExecutingLibrary = Directory.GetParent(Assembly.GetExecutingAssembly().Location).FullName;
foreach (KeyValuePair<string, string> moduleFilePath in modulesFilePaths)
{
var referenceUri = Path.Combine(pathToExecutingLibrary, moduleFilePath.Key);
var assembly = Assembly.LoadFrom(referenceUri);
var type = assembly.GetType(moduleFilePath.Value);
moduleCatalog.AddModule(
new ModuleInfo(type)
{
ModuleName = type.Name,
Ref = referenceUri,
InitializationMode = InitializationMode.WhenAvailable
});
}
moduleCatalog.Initialize();
}
protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
ConfigureViewModelLocator();
var containerExtension = CreateContainerExtension();
containerRegistry.RegisterInstance(containerExtension);
// These methods have been commented out they are use to register all the types of the application.
//RegisterSettings(containerRegistry);
//RegisterServices(containerRegistry);
//RegisterHandlers(containerRegistry);
//RegisterWrappers(containerRegistry);
containerRegistry.RegisterInstance(Dispatcher.CurrentDispatcher);
}
protected override Window CreateShell()
{
Window mainShell = Container.Resolve<MainShell>();
return mainShell;
}
}
}
You're doing too much and the wrong things in your overrides. Example: RegisterTypes should just register types...
protected override void RegisterTypes(IContainerRegistry containerRegistry)
{
// this has already been called by the base class: ConfigureViewModelLocator();
// this has also been called by the base class: var containerExtension = CreateContainerExtension();
// containerRegistry.RegisterInstance(containerExtension);
// These methods have been commented out they are use to register all the types of the application.
//RegisterSettings(containerRegistry);
//RegisterServices(containerRegistry);
//RegisterHandlers(containerRegistry);
//RegisterWrappers(containerRegistry);
containerRegistry.RegisterInstance(Dispatcher.CurrentDispatcher);
}
You should review the source code to get an understanding of how the overrides are supposed to be called. Essentially, they should not call each other, just do their own work.

How to register service at UWP project

I am trying to register alert service ( message dialog) at setup.cs for this method
protected override void InitializePlatformServices() {
base.InitializePlatformServices();
Mvx.RegisterSingleton<IAlertService>(new AlertService());
}
but i also have this exception http://prntscr.com/krpbcw
For services which has implementation in native projects.
Go to Setup.cs
protected override IMvxApplication CreateApp(){
Mvx.RegisterType< IAlertService, AlertService >();
}
Know one thing, AlertService implements IAlertService

Getting Java.Lang.NullPointerException when trying to open GPS Settings page using Xamarin

I am getting the following error when trying to open GPS settings page if GPS is not enabled (within Xamarin):
Unknown identifier: StartActivity
Unhandled Exception:
Java.Lang.NullPointerException:
Can somebody please guide where am I getting wrong?
This My Interface
namespace MyApp
{
public interface GpsSettings
{
void showGpsSettings();
}
}
This the Implementation
[assembly: Xamarin.Forms.Dependency(typeof(GpsSettingsImplementation))]
namespace MyApp.Droid
{
public class GpsSettingsImplementation : Activity, GpsSettings
{
public GpsSettingsImplementation()
{
}
public void showGpsSettings()
{
var intent = new Intent(Android.Provider.Settings.ActionLocationSourceSettings);
StartActivity(intent);
}
}
}
This is how I call my function on button click
DependencyService.Get<GpsSettings>().showGpsSettings();
An existing Activity instance has a bit of work that goes on behind
the scenes when it's constructed; activities started through the
intent system (all activities) will have a Context reference added to
them when they are instantiated. This context reference is used in the
call-chain of StartActivity.
So, the Java.Lang.NullPointerException seen after invoking
StartActivity on your Test activity instance is because the Context
inside that instance has never been set. By using the new operator to
create an activity instance you've circumvented the normal way
activities are instantiated, leaving your instance in an invalid
state!
ref: https://stackoverflow.com/a/31330999/5145530
The above error can be resolved in the following manner:
[assembly: Xamarin.Forms.Dependency(typeof(GpsSettingsImplementation))]
namespace MyApp.Droid
{
public class GpsSettingsImplementation : Activity, GpsSettings
{
public GpsSettingsImplementation()
{
}
public void showGpsSettings()
{
var intent = new Intent(Android.Provider.Settings.ActionLocationSourceSettings);
intent.SetFlags(ActivityFlags.NewTask);
Android.App.Application.Context.StartActivity(intent);
}
}
}

Java.Lang.UnsatisfiedLinkError: Native method not found: onResume with Xamarin

This class definition causes an immediate runtime crash on Xamarin for Android.
public class BaseCompatActivity : Android.Support.V7.App.AppCompatActivity
{
protected override void OnResume()
{
base.OnResume();
}
}
The error message is:
Java.Lang.UnsatisfiedLinkError: Native method not found: md5e8727ee9d36911e204981187fd2b13a2.BaseCompatActivity.n_onResume:()V
I have an inheritance chain that goes like this
MainActivity > DrawerActivity > BaseCompatActivity > AppCompatActivity
If I override OnResume in MainActivity or DrawerActivity, there is no problem. It is only if I override it in BaseCompatActivity that I get that error message.
This happens when running API level 17 in the emulator. It does not happen when running on an API level 22 device.
What could be causing this mysterious behaviour?

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