I am getting the following exception when trying to build my Xamarin.Forms iOS project...
Target _CoreCompileImageAssets: Tool /Applications/Xcode.app/Contents/Developer/usr/bin/actool execution started with arguments: --errors --warnings --notices --output-format xml1 --output-partial-info-plist "/Volumes/MacBook Pro Backup/Xamarin/NSE/iOS/obj/iPhoneSimulator/Debug/device-builds/iphone7.1-11.3/actool/partial-info.plist" --app-icon AppIcons --launch-image LaunchImage --compress-pngs --filter-for-device-model iPhone7,1 --target-device iphone --minimum-deployment-target 7.1 --platform iphonesimulator --compile "/Volumes/MacBook Pro Backup/Xamarin/NSE/iOS/obj/iPhoneSimulator/Debug/device-builds/iphone7.1-11.3/actool/bundle" "/Volumes/MacBook Pro Backup/Xamarin/NSE/iOS/obj/iPhoneSimulator/Debug/device-builds/iphone7.1-11.3/actool/cloned-assets/Resources/Images.xcassets" /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error : actool exited with code 255 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: The "ACTool" task failed unexpectedly. /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: System.ArgumentException: Failed to parse PList data type: ---> System.ArgumentException: Must specify valid information for parsing in the string. /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at System.Enum+EnumResult.SetFailure (System.Enum+ParseFailureKind failure, System.String failureMessageID, System.Object failureMessageFormatArgument) [0x00024] in /Users/builder/jenkins/workspace/build-package-osx-mono/2017-12/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/enum.cs:318 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at System.Enum.TryParseEnum (System.Type enumType, System.String value, System.Boolean ignoreCase, System.Enum+EnumResult& parseResult) [0x00077] in /Users/builder/jenkins/workspace/build-package-osx-mono/2017-12/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/enum.cs:396 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at System.Enum.Parse (System.Type enumType, System.String value, System.Boolean ignoreCase) [0x00010] in /Users/builder/jenkins/workspace/build-package-osx-mono/2017-12/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/enum.cs:370 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at System.Enum.Parse (System.Type enumType, System.String value) [0x00000] in /Users/builder/jenkins/workspace/build-package-osx-mono/2017-12/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/enum.cs:362 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PropertyListFormat+XmlFormat+Context.ReadObjectHead () [0x00018] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: --- End of inner exception stack trace --- /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PropertyListFormat+XmlFormat+Context.ReadObjectHead () [0x00048] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PropertyListFormat+XmlFormat+Context..ctor (System.Xml.XmlReader reader) [0x0000f] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PropertyListFormat+XmlFormat.StartReading (System.IO.Stream input) [0x0008a] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PropertyListFormat.CreateReadContext (System.IO.Stream input) [0x00010] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PObject.FromFile (System.String fileName, System.Boolean& isBinary) [0x00024] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PDictionary.FromFile (System.String fileName, System.Boolean& isBinary) [0x00001] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.PDictionary.FromFile (System.String fileName) [0x00001] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.Tasks.XcodeCompilerToolTask.Compile (Microsoft.Build.Framework.ITaskItem[] items, System.String output, Microsoft.Build.Framework.ITaskItem manifest) [0x002d0] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Xamarin.MacDev.Tasks.ACToolTaskBase.Execute () [0x009ba] in <35965be2bb8347aa861de1a3bb9a5f2b>:0 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute () [0x00023] in /Users/builder/jenkins/workspace/build-package-osx-mono/2017-12/external/bockbuild/builds/msbuild-15/src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs:631 /Library/Frameworks/Mono.framework/External/xbuild/Xamarin/iOS/Xamarin.iOS.Common.targets(1211,3): error MSB4018: at Microsoft.Build.BackEnd.TaskBuilder+<ExecuteInstantiatedTask>d__26.MoveNext () [0x00212] in /Users/builder/jenkins/workspace/build-package-osx-mono/2017-12/external/bockbuild/builds/msbuild-15/src/Build/BackEnd/Components/RequestBuilder/TaskBuilder.cs:787 Done building target "_CoreCompileImageAssets" in project "NSE.iOS.csproj" -- FAILED.

Hello, I am working in xamarin forms for developing app from past few months, I need to implement push notifications in my app where user will be notified as any changes occurs in server database, but I am not getting proper reference anywhere for setting push notifications from web services to mobile in cross platform manner. Can anyone help me with reference links or any samples for implementing push notifications in xamarin.forms app?

I have implemented native Google sign-in into one of my Xamarin Forms project using page renderer for Android. Till now its working fine but now it isn't. I used GoogleSignInOptions class.

In Activity Result

GoogleSignInResult result = Auth.GoogleSignInApi.GetSignInResultFromIntent(e.Data);

result.IsSuccess always false. Prior it working fine. I have checked with my Google developer console and everything is just fine nothing changed there.

Please help.

When i am viewing xamarin form application in samsung tab with xamarin live player style sheet is not loading or working.

some times it gives the error like "Type StyleSheet not found in xmlns in xamarin" when I am running it in the android emulator then it is working properly

<ContentPage.Resources>

</ContentPage.Resources>
and I have created a file called home.cs inside the content folder and made build action "Embedded resource"

Can anyone tell what is issue??

Hi Everyone,

I have created a Xamarin.Forms application. In my application when I click on any button my app is crashing with exception Cannot access a disposed object.Object name: 'Xamarin.Forms.Platform.Android.Platform+DefaultRenderer'. Here is the crash log

            `  Message: Cannot access a disposed object.Object name: 'Xamarin.Forms.Platform.Android.Platform+DefaultRenderer'. StackTrace:   at Java.Interop.JniPeerMembers.AssertSelf (Java.Interop.IJavaPeerable self) [0x00029] in <3cb12bce834a498199b2be6cd3e00922>:0   at Java.Interop.JniPeerMembers+JniInstanceMethods.InvokeVirtualInt32Method (System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters) [0x00000] in <3cb12bce834a498199b2be6cd3e00922>:0   at Android.Views.View.get_Visibility () [0x0000a] in <ff199c98c3f84852925dd37a0ef6113a>:0   at Xamarin.Forms.Platform.Android.VisualElementTracker.UpdateIsVisible () [0x0001d] in <fb1b373bb41f422cab210b1850374a59>:0   at Xamarin.Forms.Platform.Android.VisualElementTracker.HandlePropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x002dc] in <fb1b373bb41f422cab210b1850374a59>:0   at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs)  at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x00012] in <42fe931976e64c199eddde45068a6c09>:0   at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in <42fe931976e64c199eddde45068a6c09>:0   at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.BindableObject+SetValueFlags attributes, System.Boolean silent) [0x000fb] in <42fe931976e64c199eddde45068a6c09>:0   at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.BindableObject+SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0014b] in <42fe931976e64c199eddde45068a6c09>:0   at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean fromTarget) [0x001f9] in <42fe931976e64c199eddde45068a6c09>:0   at Xamarin.Forms.BindingExpression.Apply (System.Boolean fromTarget) [0x0003e] in <42fe931976e64c199eddde45068a6c09>:0   at Xamarin.Forms.BindingExpression+BindingExpressionPart.<PropertyChanged>b__47_0 () [0x00000] in <42fe931976e64c199eddde45068a6c09>:0   at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in <ff199c98c3f84852925dd37a0ef6113a>:0   at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in <ff199c98c3f84852925dd37a0ef6113a>:0   at (wrapper dynamic-method) System.Object.ddb67896-6c72-437b-b11e-096da6069f88(intptr,intptr) Method: ; AssertSelf`

I am unable to figure out the exact reason. Is there any solution to fix it.

Hi Everyone,

I have created a Xamarin.Forms application. In my application when I click on any button my app is crashing with exception Cannot access a disposed object.Object name: 'Xamarin.Forms.Platform.Android.ImageRenderer'. Here is the crash log

Message: Cannot access a disposed object.Object name: 'Xamarin.Forms.Platform.Android.ImageRenderer'.StackTrace: at Java.Interop.JniPeerMembers.AssertSelf (Java.Interop.IJavaPeerable self) [0x00029] in <2adcca1486484b3b977b571b94c7903a>:0 at Java.Interop.JniPeerMembers+JniInstanceMethods.InvokeVirtualInt32Method (System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters) [0x00000] in <2adcca1486484b3b977b571b94c7903a>:0 at Android.Views.View.get_Visibility () [0x0000a] in <c38061fd62ab40a98586383f36964d81>:0 at Xamarin.Forms.Platform.Android.VisualElementTracker.UpdateIsVisible () [0x00035] in <fb1b373bb41f422cab210b1850374a59>:0 at Xamarin.Forms.Platform.Android.VisualElementTracker.HandlePropertyChanged (System.Object sender, System.ComponentModel.PropertyChangedEventArgs e) [0x002dc] in <fb1b373bb41f422cab210b1850374a59>:0 at (wrapper delegate-invoke) <Module>.invoke_void_object_PropertyChangedEventArgs(object,System.ComponentModel.PropertyChangedEventArgs) at Xamarin.Forms.BindableObject.OnPropertyChanged (System.String propertyName) [0x00012] in <42fe931976e64c199eddde45068a6c09>:0 at Xamarin.Forms.Element.OnPropertyChanged (System.String propertyName) [0x00000] in <42fe931976e64c199eddde45068a6c09>:0 at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.BindableObject+SetValueFlags attributes, System.Boolean silent) [0x000fb] in <42fe931976e64c199eddde45068a6c09>:0 at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.BindableObject+SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x0014b] in <42fe931976e64c199eddde45068a6c09>:0 at Xamarin.Forms.BindingExpression.ApplyCore (System.Object sourceObject, Xamarin.Forms.BindableObject target, Xamarin.Forms.BindableProperty property, System.Boolean fromTarget) [0x001f9] in <42fe931976e64c199eddde45068a6c09>:0 at Xamarin.Forms.BindingExpression.Apply (System.Boolean fromTarget) [0x0003e] in <42fe931976e64c199eddde45068a6c09>:0 at Xamarin.Forms.BindingExpression+BindingExpressionPart.<PropertyChanged>b__47_0 () [0x00000] in <42fe931976e64c199eddde45068a6c09>:0 at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in <c38061fd62ab40a98586383f36964d81>:0 at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in <c38061fd62ab40a98586383f36964d81>:0 at (wrapper dynamic-method) System.Object.835897aa-40b8-46da-a402-79a92ebbf907(intptr,intptr)Method: ; AssertSelf

I am unable to figure out the exact reason. Is there any solution to fix it.

I'm using MVVM, I'm finding that trying to detect a row being clicked to invoke a command painful to implement. It would seem that there's no ItemSelected that takes a Command, so I've tried to use the TapGestureRecognizer with no success..
my viewcell is in c# as its bit complex to convert into xaml.

InSide ViewCell---

TapGestureRecognizer taponimgcheckuncheck = new TapGestureRecognizer();
taponimgcheckuncheck.SetBinding(TapGestureRecognizer.CommandProperty,"TapOnLogo");
imgcheckuncheck.GestureRecognizers.Add(taponimgcheckuncheck);

And my viewmodel is like---
public ICommand TapOnLogo{

        get{
            return new Command(() =>
            {
                Application.Current.MainPage.DisplayAlert("TapOnLogo","TapOnLogo","ok");
            });
        }
    }

I am trying to get Visual Studio 2015 set up to do Xamarin Forms.
I have two issues (that I know of)

1) When in VS I navigate to: Tools->Android-> all the options are grayed

2) When I do an Install or Repair I get messages indicating that it had problems downloading Android SDK Setup (API Level 19 and 21). Same thing for 22 and 23.
I have what looks like an Android SDK at :
C:\Program Files (x86)\Android\android-sdk
And there is a link to it in Tools->Options->Xamarin->Android Settings.

Any insight is appreciated.

Hi,

I have been having issues with using the ScrollToAsync function of a ScrollView when running on Android, not tested on iOS yet.
I'm using Xamarin.Forms version 2.5.1.444934 using .Net Standard
Testing on the Android Emulator (8.0, API26) and a Google Pixel (8.1 API27), both have the same issue.

I use NavigationPage and Navigation.PushAsync to move between pages (therefore have navigation bars on every page).

I want to create an auto populate field control, the user types in the first few letters and I look up the results in a database / static list of string and display the results below for the user to click/tap.
I have this working using a composite control (the contents of the frame marked interesting below).
The problem I have is scrolling the view to show the results.

My page has this layout hierarchy:-

ContentPage
    StackLayout
        ScrollView
            StackLayout
                Frame (some label and entry fields inside a stack layout)
                Frame (some label and entry fields inside a stack layout)
                Frame (some label and entry fields inside a stack layout)
                Frame (the interesting one that deals with scrolling)
                    StackLayout
                        Heading Label
                        StackLayout
                            Label x:Name="ScrollToLabel"
                            Entry x:Name="ScrollToEntry"
                            Grid x:Name="ScrollToGrid"
                            Entry x:Name="Hidden" Text="I should stay visible as you type"
                        /StackLayout
                    /StackLayout
                /Frame
                Frame (some label and entry fields inside a stack layout)
                Frame (some label and entry fields inside a stack layout)
            /StackLayout
        /ScrollView
        StackLayout
            Button Text = Done
        /StackLayout
    /StackLayout
/ContentPage

When the user clicks/taps in to ScrollToEntry, the keyboard opens and pans the control to above the keyboard (ok so far).
When the user starts typing in ScrollToEntry, the code populates ScrollToGrid with up to 5 results.
At this point I want to make sure that the grid results are visible for the user to tap on.
I have tried 2 different options, ScrollToAsync(ScrollToLabel, Start) and ScrollToAsync(Hidden, MakeVisible).

Neither work as I would like 100% of the time.

ScrollToAsync(ScrollToLabel, Start)

If the ScrollToEntry is at the bottom of the screen, the navigation bar is hidden and the view pans up too far.
The ScrollToLabel is now off the top of the screen.
When the second letter is clicked/tapped, the Navigation bar is restored and the scroll scrolls correctly, ScrollToLabel at the top of the screen.
If the ScrollToEntry is near the top of the screen, the navigation bar is not hidden and it scrolls correctly.

ScrollToAsync(Hidden, MakeVisible)
This is my preferred option because it would only scroll as far as needed to display all the results (not all the way to the top).
This works even worse than the first one.
In most cases, it does not scroll at all, I assume it thinks it already visible but is actually behind the keyboard?
If it does scroll, the label Hidden is still not displayed (I tested with both a HeightRequest="0" version and a visible version, both the same result).

I tried using the below code to change the adjust to resize.
Application.Current.On<Xamarin.Forms.PlatformConfiguration.Android>().UseWindowSoftInputModeAdjust(WindowSoftInputModeAdjust.Resize);

2 issues,
1. Because it resizes, the Done button now is above the keyboard, taking up space.
2. When clicking the hardware back button (not the done or navigation back button) the previous view now has a white space where the keyboard was.
If using the done or navigation back, the screen initially appears with the white space but then refreshes to full screen.

I have created a sample app that highlights the issues (by default using pan, not resize) attached.
Its the most simple version of the layout I'm using.

Am I doing something wrong or is this just how it works?
If its how it works, this must be a bug?
If I'm doing it wrong, can someone tell me what or suggest a different way of doing it?

Thanks

I am working with list view using tamarin forms.
I need to change the background color and text color of the selected item in list view. I have achieved the background color change using custom renderer.
But i am not able to change the text color of selected item.
Can you please help me out. I have given the code snippet here. This is for IOS platform.

public class CustomTextCellRenderer: ViewCellRenderer
{
private UIView bgView;

    public override UITableViewCell GetCell (Cell item, UITableViewCell reusableCell, UITableView tv)
    {
        var cell = base.GetCell (item, reusableCell, tv);
        if (bgView == null)
        {
            bgView = new UIView {
                BackgroundColor = UIColor.FromRGB(6,51,110),
            };
        }

        cell.SelectedBackgroundView = bgView;
        cell.TextLabel.HighlightedTextColor = UIColor.Red;
        return cell;
    }

}

Is there a way to indicate to the ListView that every other row is a different color?

        var list = new ListView()
        {
            ItemTemplate = new DataTemplate(typeof(FinancialCell)),
             .....?
        }

I haven't seen an API for it.

In the above FinancialCell (ViewCell), perhaps do we need to do it manually?

How to display reply notification that "Success" or "failure" for just a flash after login?

Hello.
is possible to do a keyboard to cross platforms as like the photo ?
I asking for complete DNI.!

Hi i'm having trouble in binding data of multiple classes to a single list view.

How to deselect clicked one in master details slide menu in xamarin forms after processed?

Hi why my app crashes after log in and doesnt go to my masterdetailpage

How to check a content page already have on navigation stack or not in xamarin forms?

I would like to know how to create an image in code.

For example A blue field X by X pixels with a red line and some text. I have a goal of adding a splash to an actual image similar to how the sports channels have a stripe and some words. Right now I am focusing on the basics of adding elements to a new blank image.

This type of image with transparencies overlay is a related goal.

The very basics of this can be done trivially in regular .net like this:
...
Bitmap flag = new Bitmap(200, 100);
Graphics flagGraphics = Graphics.FromImage(flag);
int red = 0;
int white = 11;
while (white <= 100) {
flagGraphics.FillRectangle(Brushes.Red, 0, red, 200,10);
flagGraphics.FillRectangle(Brushes.White, 0, white, 200, 10);
red += 20;
white += 20;
}
...

I have spent a lot of time on other things that have had a simple answer if I had asked first. Hoping this is like that.

My thanks in advance

Hello, Can anyone help me for displaying alert when internet connection of device is disabled, as application needs internet connection to perform its tasks. How can I check whether internet connection of particular device is on or off and if internet connection is off then whenever app starts it should show such kind of error to inform user for enabling internet connection.

I'm having a problem where the ZXing.Net.Mobile.Forms is causing my app to crash at LoadApplication(new App()); At first I was trying to integrate the package into an existing solution. So, I tried creating a new one with the same results.

If I remove ZXing.Net.Mobile.Forms and just have ZXing.Net.Mobile installed, the app works just fine.

As always, thanks for any help.