I have a Xamarin Forms 2.0 application that uses ZXing.Net.Mobile and ZXing.Net.Mobile.Forms version 2.0.3.1. I'm trying to build a simple QR code scanner, but whenever I launch the ZXingScannerPage on Android I can see the default overlay (with the text and the red line) but I don't see the output of the camera so I can't actually scan anything. I have already listed the Camera permission in my AndroidManifest:

I tried the sample code from the readme: https://github.com/Redth/ZXing.Net.Mobile as well as from their Samples/Forms project. I now have this code:

`private async void OnScanQrClicked(object sender, EventArgs e)
{
_scannerPage = new ZXingScannerPage();
_scannerPage.OnScanResult += HandleScanResult;

await Navigation.PushAsync(_scannerPage);

}

private void HandleScanResult(Result result)
{
_scannerPage.IsScanning = false;

Device.BeginInvokeOnMainThread(() =>
{
    Navigation.PopAsync();
    DisplayAlert("Scanned code", result.Text, "OK");
});

}`

Some more specs: I'm running Android 5.1 on a Moto G (v1).

Why am I not seeing the output of the camera?

I need to implement Copy to Clipboard within my app. Is there a component/plug-in to support this, or am I back to writing more DependencyServices?

Thanks,

John H.

What's the best way to access the phonebook and send sms to a contact on Xamarin.Forms. Is there any good package or plugin fro Xamarin.Forms I can use to accomplish this task? Keep in mind I want it to be cross-platform. Thank you in advance for the replies.

Hi guys,

I am new to XF and just trying to learn Binding a bit.

In my XAML, I have the following label:

<Label HorizontalOptions="Center" VerticalOptions="Center" Grid.Column="0" Grid.ColumnSpan="3" Text="{Binding Credit}" />

and in the code behind, I have the following:

              private string credit { get; set; } 
              public string Credit  {
                        get
                        {
                            return credit; 

                        }
                        set
                        {
                            credit = value;
                    }
                             }

So when I set an initial value, for example, credit = "0.00" it works perfectly fine but my problem is setting it:

   private void Button_OnClicked(object sender, EventArgs e)
        {
        var crdString = Credit;

            float crd = float.Parse(crdString);
            crd++;
            credit = crd.ToString();
        }

But it does not update the UI.

P.S I have also set the BindingContext :

        InitializeComponent ();
            BindingContext = this;

xam.plugin.media not working on Android (Works on UWP)

I've started xamarin forms recently and have been trying to get xam.plugin.media to work. I scoured the web and am at the end of my wisdom.

I'm checking if I have permissions, a camera is available, photo is supported and even then it crashes.
Plugins were implemented as stated by the readme and/or fellowbloggers.
Permissions set in my xamarin liveplayer device.

Even tried example solutions but since they are usually out of date and xamarin aswell as the plugin doesnt quite like that they didnt work aswell.

Solution github.com/peyter213/xam_plugin_media-Issue

Thanks to anyone that dares to take a look.

Error: i.imgur.com/GrarxPq.png

Codeexample of the MainPage

MainPage.xaml.cs
` private async void Btn_takePhoto_Clicked(object sender, EventArgs e)
{
try
{
var status = await CrossPermissions.Current.CheckPermissionStatusAsync(Permission.Camera);
if (status != PermissionStatus.Granted)
{
if (await CrossPermissions.Current.ShouldShowRequestPermissionRationaleAsync(Permission.Camera))
{
await DisplayAlert("Camera Permission", "Allow SavR to access your camera", "OK");
}

                var results = await CrossPermissions.Current.RequestPermissionsAsync(new[] { Permission.Camera });
                status = results[Permission.Camera];
            }

            if (status == PermissionStatus.Granted)
            {

                await CrossMedia.Current.Initialize();

                if (!CrossMedia.Current.IsCameraAvailable || !CrossMedia.Current.IsTakePhotoSupported)
                {
                    await DisplayAlert("No Camera", ":( No camera available.", "OK");
                    return;
                }
                var s = CrossMedia.Current.IsCameraAvailable;
                var file = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions
                {
                    PhotoSize = PhotoSize.Medium,

                });

                if (file == null)
                    return;
            }
            else if (status != PermissionStatus.Unknown)
            {
                await DisplayAlert("Camera Denied", "Can not continue, try again.", "OK");
            }
        }
        catch (Exception ex)
        {

            await DisplayAlert("Error", "Camera Not Available", "OK");
        }
    }`

Hi,
I'm trying to do an alternative ListView where I want to be able to change and update labels after the "cells" are created. This is my first test, just put alot of stacklayouts in a scrollview. The problem is that I cant figure out how to change the ".Text" parameter for the labels based on their ClassIds.
This simple test should work as that if I click on for example the button with the ClassId "1" the Text of the Label with the ClassId "lbl1" should change to "Hello". So I guess the main question is how to reference an item based on it's ClassId? Hope this makes some sense..

Best regards
Magnus

using System;
using Xamarin.Forms;

namespace TestScroll2
{
    public partial class TestScroll2Page : ContentPage
    {
        StackLayout mainLayout;
        public TestScroll2Page()
        {
            mainLayout = new StackLayout
            {
                Margin = new Thickness(0, 0, 0, 0)
            };

            for (var i = 0; i < 40; i++)
            {
                var stackLayout = new StackLayout();
                stackLayout.ClassId = "Stack" + i;

                var stackLabel = new Label()
                {
                    Text = "Separators in stack layout " + i
                };
                stackLabel.ClassId = "lbl"+i;
                var stackButton = new Button()
                {
                    Text="Click Me"
                };
                stackButton.ClassId=""+i;
                stackButton.Clicked += OnButtonClicked;

                stackLayout.Children.Add(stackLabel);
                stackLayout.Children.Add(stackButton);

                stackLayout.BackgroundColor = Color.Gray.MultiplyAlpha(0.2);

                mainLayout.Children.Add(stackLayout);
            }

            Content = new ScrollView() { 
                Margin = new Thickness(0, 30, 0, 0),
                Content = mainLayout 
            };
        }
        void OnButtonClicked(object sender, EventArgs e)
        {
            Button btn = (Button)sender;
            StackLayout stl = (StackLayout)btn.Parent;
            DisplayAlert("Alert", "OnButtonClicked: "+btn.Parent.ClassId , "OK"); // this works
            //this.FindByName<Label>("lbl1").Text="Hello"; -> this is where I like to update the corresponding label
        }
    }
}

hi,
i have visual studio enterprise 2017 and i installed all the things to be worked with xamarin.
i did it maybe 5 times in two weeks and im getting crazy.
when i choose in visual studio file->new->project, i choose in the left pannel for c#, cross platform

i have only two options:
1)UI Test APP
2)class library(xamarin forms)

everyone i know include posts at the internet have a third option:
3)Cross platform App(xamarin forms or native)

which is the exactly i need!

when i choose the second option i can choose between shared project or .net standard. this thing its only in my computer
everyone else has portable class instead of the .net standard option and i need the poratable!

what do i need to install to have the third options?
i've been trying to seek for this two weeks

please help!!!

Xamarin forms on Android.

I'm using PushModalAsync() to open a new window. Most of the time it works fine, but occasionally the new window is created but is not visible, as if it's hidden behind the previous page. The OnAppearing() event for the new page is triggered. If I tap the menu button on my tablet to bring up the list of open applications, then tap on my application to return focus to my app, then suddenly the new window pops into view. Is there a way to force the new window to pop to the top, or force a screen redraw of some kind after PushModalAsync()? This is how I'm opening the new window:

public void OpenMyNewWindow(void)
{
  try
  {
    if (myNewPage == null)
      myNewPage = new MyNewPageType();
    Navigation.PushModalAsync(myNewPage);
  }
  catch (Exception e)
  {
    // handle errors... 
  }
} 

I am trying to get a demo working that will allow me to include navigation native UWP pages and pages build using Xamarin Forms.

When I try and use the rootFrame to navigate to the first XF page I get a AccessViolationException from this code

return this._frame.Navigate(viewType, parameter);

Any thoughts as to why this might happen?

I have tried forcing the code to run on the UI thread but that didn't help
I have seen reports of that exception from WinRT when XAML pages are defined in a different assembly but I have tried navigating to native [ages in a second assembly and that worked fine so i don't think that is the issue.

Hi,

I need to have two section on the same page.
The top section(or 1st section) being the static on the page while the bottom(or 2nd section) section having multiple modelling pages on it.

Kindly suggest how it is achievable.

Thanks in advance.

This my Xaml code:

    <StackLayout VerticalOptions="EndAndExpand" Padding="0" Spacing="0" Margin="0" HorizontalOptions="FillAndExpand"
                      RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1}"
                      RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0.90}"
                      RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0.1}">

        <Grid   BackgroundColor="#e8eaf6" Padding="0" Margin="0">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="*" />
                <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>

            <StackLayout Orientation="Vertical" Grid.Column="0" HorizontalOptions="CenterAndExpand" VerticalOptions="Center">
                <Image  Source="bb_YayinEkrani.png"  WidthRequest="30" HeightRequest="30" Opacity="0.6" />

            </StackLayout>

            <StackLayout Orientation="Vertical"  Grid.Column="1"  HorizontalOptions="CenterAndExpand" VerticalOptions="Center">
                <Image Source="bb_HaberMasasi.png" WidthRequest="30" HeightRequest="30"  Opacity="0.6">
                    <Image.GestureRecognizers>
                        <TapGestureRecognizer Tapped="ImgHaberMasasi_Tapped"/>
                    </Image.GestureRecognizers>
                </Image>

            </StackLayout>

            <StackLayout Orientation="Vertical"  Grid.Column="2"  HorizontalOptions="CenterAndExpand" VerticalOptions="StartAndExpand">

                <Image  Source="aalogo2.png"  WidthRequest="40" HeightRequest="40" >
                    <Image.GestureRecognizers>
                        <TapGestureRecognizer Command="{Binding SlideOpenCommand}" Tapped="Logo_Tapped"/>
                    </Image.GestureRecognizers>
                </Image>
            </StackLayout>
            <StackLayout Orientation="Vertical"  Grid.Column="3"  HorizontalOptions="CenterAndExpand" VerticalOptions="Center">
                <StackLayout Orientation="Horizontal" HorizontalOptions="CenterAndExpand" VerticalOptions="Center">
                    <Image  Source="bb_Bell.png"  WidthRequest="30" HeightRequest="30" Opacity="0.6"/>
                   <badge:BadgeView Text="21" BadgeColor="Red" VerticalOptions="Start" HorizontalOptions="End" />
                </StackLayout>

            </StackLayout>
            <StackLayout Orientation="Vertical"  Grid.Column="4"  HorizontalOptions="CenterAndExpand" VerticalOptions="Center">
                <StackLayout Orientation="Horizontal" HorizontalOptions="Center" VerticalOptions="Center">
                    <Image  Source="bb_Profile.png"  WidthRequest="30" HeightRequest="30" Opacity="0.6">
                        <Image.GestureRecognizers>
                            <TapGestureRecognizer Tapped="ImgProfile_Tapped"/>
                        </Image.GestureRecognizers>
                    </Image>
                    <badge:BadgeView Text="8" BadgeColor="Red" VerticalOptions="Start" HorizontalOptions="End" />
                </StackLayout>

            </StackLayout>
        </Grid>
    </StackLayout>
</RelativeLayout>

Hello,

I'm a newbie in Xamarin and I'm trying to achieve something simple... I have a button and I want to Login with Twitter (I'm working on Android).

On shared code I have:
`public void StartTwitterLogin()
{
var auth = new OAuth1Authenticator(
consumerKey: "*******************",
consumerSecret: "*********************************************************",
requestTokenUrl: new Uri(twitter.requestTokenUrl),
authorizeUrl: new Uri(twitter.authorizeUrl),
accessTokenUrl: new Uri(twitter.accessTokenUrl),
callbackUrl: new Uri(twitter.callbackUrl)
);
auth.AllowCancel = false;
auth.Completed += OnAuthCompleted;
auth.Error += OnAuthError;
var presenter = new Xamarin.Auth.Presenters.OAuthLoginPresenter();
presenter.Login(auth);

            }

`
So I have this function bonded to my button. But when I click it, it launches an alert saying "socket not connected"... anyone can help?

Thank you in advance

I would like to ask is there even possible to capture app crash report from the phone and write it into another text file?

I have forms app, and I have custom label as following,

public class HtmlFormattedLabel : Label
    {
        public float mySize { get; set; }
    }

and I have custom renderer in both android and ios as following:

Android:

[assembly: ExportRenderer(typeof(HtmlFormattedLabel), typeof(HtmlFormattedLabelRenderer))]
namespace HBRS.Droid.Renderers
{
    public class HtmlFormattedLabelRenderer : LabelRenderer
    {

        public HtmlFormattedLabelRenderer(Context context) : base(context)
        {

        }
        protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
        {
            base.OnElementChanged(e);

            HtmlFormattedLabel view = (HtmlFormattedLabel)Element;
            if (view == null) return;

            Control.Gravity = Android.Views.GravityFlags.Right;
            Control.SetTextSize(Android.Util.ComplexUnitType.Sp, view.mySize);

            if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.N)
                Control.SetText(Html.FromHtml(view.Text.ToString(), FromHtmlOptions.ModeLegacy), TextView.BufferType.Normal);
            else
                Control.SetText(Html.FromHtml(view.Text.ToString()), TextView.BufferType.Normal);
        }
    }
}

iOS

    [assembly: ExportRenderer(typeof(HtmlFormattedLabel), typeof(HtmlFormattedLabelRenderer))]
    namespace HBRS.iOS.Renderers
    {
        public class HtmlFormattedLabelRenderer : LabelRenderer
        {
            protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
            {
                base.OnElementChanged(e);

                var view = (HtmlFormattedLabel)Element;
                if (view == null) return;
                UIStringAttributes te = new UIStringAttributes();
                var attr = new NSAttributedStringDocumentAttributes();
                var nsError = new NSError();
                attr.DocumentType = NSDocumentType.HTML;
                attr.StringEncoding = NSStringEncoding.UTF8;
                attr.ViewMode = NSDocumentViewMode.PageLayout;
                Control.AttributedText = new NSAttributedString(view.Text, attr, ref nsError);
            }
        }
    }

the problem that in android, the renderer applied to all labels in the app, (when I change size of the custom label all the label sizes changes)

Hey,

I created a Listview inside a CarouselView, but when i want to scroll in my listview, my carousel can take the focus and it can horizontal scroll too.

How can I lock my carouselView ?

Thanks

I have an ObservableCollection with list of users data which is wrapped for multiselect page.
I added SearhBox to the multiselect page but I can not make it work.
Here is an example of code:

public class WrappedItemSelectionTemplate : ViewCell
            {
                public WrappedItemSelectionTemplate() : base()
                {


                    Label Title = new Label() { TextColor = Color.Black };

                    Title.SetBinding(Label.TextProperty, new Binding("Item.Title"));
                    Label Email = new Label() { FontSize = 14 };

                    Email.SetBinding(Label.TextProperty, new Binding("Item.Email"));

                    Switch mainSwitch = new Switch() { HorizontalOptions = LayoutOptions.End };
                    mainSwitch.SetBinding(Switch.IsToggledProperty, new Binding("IsSelected"));


                    StackLayout Stack = new StackLayout();

                    Stack.Children.Add(Title);
                    Stack.Children.Add(Email);
                    Grid grid = new Grid();
                    grid.Children.Add(Stack, 0,0);
                    grid.Children.Add(Email, 0, 1);
                    grid.Children.Add(mainSwitch, 1, 0);
                    View = grid;
                }
            }
            public List<WrappedSelection<T>> WrappedItems = new List<WrappedSelection<T>>();

            public SelectMultipleBasePage(List<T> items)
            {
                WrappedItems = items.Select(item => new WrappedSelection<T>() { Item = item, IsSelected = false }).ToList();
                ListView mainList = new ListView()
                {
                    ItemsSource = WrappedItems,
                    ItemTemplate = new DataTemplate(typeof(WrappedItemSelectionTemplate)),
                };

                mainList.ItemSelected += (sender, e) =>
                {
                    if (e.SelectedItem == null) return;
                    var o = (WrappedSelection<T>)e.SelectedItem;
                    o.IsSelected = !o.IsSelected;
                    ((ListView)sender).SelectedItem = null; //de-select
                };

                // SearchBar added
                StackLayout Stack = new StackLayout();
                SearchBar Search = new SearchBar(); 
                Stack.Children.Add(Search);
                Stack.Children.Add(mainList);
                Search.TextChanged += (sender, e) =>
                {
                    SearchBar_TextChanged();
                };
                Content = Stack;

                void SearchBar_TextChanged()
                {


                }
            }

When I ussed SearchBox in my cases before I was filtering an ObservableCollection like:

new ObservableCollection<Models.M_UsersAndGroups>(
from user in userList           
where (!String.IsNullOrEmpty(user.Title) && user.Title.IndexOf(keyword, StringComparison.OrdinalIgnoreCase) >= 0) 
select user)

But I can't do the same because it's wrapped. How I can use SearhBox for field Title in that case?

I've a view with a grid with 3 rows. In the first row ( 0 ) there is an image like as header. I wish to collapse the row0 when I tap on image to I've more space in the view.
How doing?

Hi everybody!
How to drawing a Rectangle using SkiaSharp?
If you have better way, please tell me!
Thank you!

Hey Guys,
I am facing a problem with my android project of my Xamairn.Forms Application.

When I run the Solution I get the following Exception:
07-19 15:02:10.323 E/mono ( 3650): 07-19 15:02:10.323 E/mono ( 3650): Unhandled Exception: 07-19 15:02:10.323 E/mono ( 3650): Java.Lang.NullPointerException: Attempt to invoke virtual method "android.content.res.Resources android.content.Context.getResources()" on a null object reference 07-19 15:02:10.323 E/mono ( 3650): at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/data/lanes/3236/ee215fc9/source/mono/external/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:143 07-19 15:02:10.323 E/mono ( 3650): at Android.Runtime.JNIEnv.CallNonvirtualVoidMethod (IntPtr jobject, IntPtr jclass, IntPtr jmethod, Android.Runtime.JValue* parms) [0x00084] in /Users/builder/data/lanes/3236/ee215fc9/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:1029 07-19 15:02:10.323 E/mono ( 3650): at Android.Runtime.JNIEnv.FinishCreateInstance (IntPtr instance, IntPtr jclass, IntPtr constructorId, Android.Runtime.JValue* constructorParameters) [0x0000b] in /Users/builder/data/lanes/3236/ee215fc9/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.cs:306 07-19 15:02:10.323 E/mono ( 3650): at Android.Views.ScaleGestureDetector..ctor (Android.Content.Context context, IOnScaleGestureListener listener) [0x000d8] in /Users/builder/data/lanes/3236/ee215fc9/source/monodroid/src/Mono.Android/platforms/android-23/src/generated/Android.Views.ScaleGestureDetector.cs:477 07-19 15:02:10.323 E/mono ( 3650): at DevExpress.Mobile.DataGrid.Android.DroidGestureRecognizerService..ctor () [0x0005c] in <filename unknown>:0 07-19 15:02:10.323 E/mono ( 3650): at DevExpress.Mobile.Forms.Init () [0x0003c] in <filename unknown>:0 07-19 15:02:10.323 E/mono ( 3650): at App4Business.Droid.MainActivity.OnCreate (Android.OS.Bundle bundle) [0x000a8] in c:\Users\pasqueju\Desktop\App4Business\App\App4Business\App4Business.Droid\MainActivity.cs:48 07-19 15:02:10.323 E/mono ( 3650): at Android.App.Activity.n_OnCreate_Landroid_os_Bundle_ (IntPtr jnienv, IntPtr native__this, IntPtr native_savedInstanceState) [0x00011] in /Users/builder/data/lanes/3236/ee215fc9/source/monodroid/src/Mono.Android/platforms/android-23/src/generated/Android.App.Activity.cs:2857 07-19 15:02:10.323 E/mono ( 3650): at (wrapper dynamic-method) System.Object:6d3f2cc8-3619-482a-a12e-1975032c5182 (intptr,intptr,intptr) 07-19 15:02:10.323 E/mono ( 3650): --- End of managed exception stack trace --- 07-19 15:02:10.323 E/mono ( 3650): java.lang.NullPointerException: Attempt to invoke virtual method "android.content.res.Resources android.content.Context.getResources()" on a null object reference 07-19 15:02:10.323 E/mono ( 3650): at android.view.ViewConfiguration.get(ViewConfiguration.java:364) 07-19 15:02:10.323 E/mono ( 3650): at android.view.ScaleGestureDetector.<init>(ScaleGestureDetector.java:207) 07-19 15:02:10.323 E/mono ( 3650): at android.view.ScaleGestureDetector.<init>(ScaleGestureDetector.java:189) 07-19 15:02:10.323 E/mono ( 3650): at md5c5e8c35f6309ca9ae42ed30d74b361ec.MainActivity.n_onCreate(Native Method) 07-19 15:02:10.323 E/mono ( 3650): at md5c5e8c35f6309ca9ae42ed30d74b361ec.MainActivity.onCreate(MainActivity.java:28) 07-19 15:02:10.323 E/mono ( 3650): at android.app.Activity.performCreate(Activity.java:6237) 07-19 15:02:10.323 E/mono ( 3650): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) 07-19 15:02:10.323 E/mono ( 3650): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
My MainAcitivity:

[Activity(Label = "App4Business", Theme = "@style/AppTheme", Icon = "@drawable/icon", ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)] public class MainActivity : XFormsApplicationDroid { protected override void OnCreate(Bundle bundle) { var container = new SimpleContainer(); container.Register<IDevice>(t => AndroidDevice.CurrentDevice); container.Register<IDisplay>(t => t.Resolve<IDevice>().Display); container.Register<INetwork>(t => t.Resolve<IDevice>().Network); Resolver.SetResolver(container.GetResolver()); base.OnCreate(bundle); Xamarin.Forms.Forms.SetTitleBarVisibility(AndroidTitleBarVisibility.Default); global::Xamarin.Forms.Forms.Init(this, bundle); Telerik.XamarinForms.Common.Android.TelerikForms.Init(); CachedImageRenderer.Init(); DevExpress.Mobile.Forms.Init(); CrossPushNotification.Initialize<CrossPushNotificationListener>("XXXXXXXXX"); CrossPushNotification.Current.Register(); //This service will keep your app receiving push even when closed. DependencyService.Register<ToastNotificatorImplementation>(); ToastNotificatorImplementation.Init(this); LoadApplication(new App()); } }

The exception is thrown at the DevExpress.Mobile.Forms.Init();
When I remove this line my App is starting. But I get confusing nullpointer's in other Plugins (suchlike Connectivity)

I would appreciate any help
Julian

Is this possible in Xamarin.forms?