Develop Reference

Rg.Plugin.PopupPage error with the call line

I installed the plugin on the 3 projects (PCL/Android/IOS)
I am using Xamarin.forms and
The line that calls the popup page shows this error message after the app started:
Unhandled Exception:
System.InvalidOperationException: Platform is not created occurred
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MenuView : ContentPage
{
List<Loja> lstLojas;
IGeolocator locator;
Loja lojaPerto;
Localizacao localizacao;
MyPopupPage s;
public MenuView()
{
s = new MyPopupPage();
InitializeComponent();
CallingGeolocatorAsync();
login();
}
void login()
{
Navigation.PushPopupAsync(s, true);
}
this is my PopUp Page.cs
using System;
using System.Threading.Tasks;
using Rg.Plugins.Popup.Pages;
using Rg.Plugins.Popup.Services;
using Xamarin.Forms;
namespace neoFly_Montana.PopUp
{
public partial class MyPopupPage : PopupPage
{
public MyPopupPage()
{
InitializeComponent();
}
private void OnClose(object sender, EventArgs e)
{
PopupNavigation.PopAsync();
}
protected override Task OnAppearingAnimationEnd()
{
return Content.FadeTo(0.5);
}
protected override Task OnDisappearingAnimationBegin()
{
return Content.FadeTo(1);
}
}
}
this is my popup xml
<?xml version="1.0" encoding="utf-8" ?>
<pages:PopupPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:pages="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
xmlns:animations="clr-namespace:Rg.Plugins.Popup.Animations;assembly=Rg.Plugins.Popup"
x:Class="neoFly_Montana.PopUp.MyPopupPage">
<!--Animations use example-->
<pages:PopupPage.Animation>
<animations:ScaleAnimation
PositionIn="Center"
PositionOut="Center"
ScaleIn="1.2"
ScaleOut="0.8"
DurationIn="400"
DurationOut="300"
EasingIn="SinOut"
EasingOut="SinIn"
HasBackgroundAnimation="True"/>
</pages:PopupPage.Animation>
<!-- Content -->
Can someone help?

You can't call that in a contructor...you need to use:
protected override void OnAppearing()
{
base.OnAppearing();
s = new MyPopupPage();
PopupNavigation.PushAsync(s, true);
}

Popuplogin.xaml:
<?xml version="1.0" encoding="UTF-8"?>
<pages:PopupPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="SeralizationApp.Views.Popuplogin"
xmlns:animations="clr-namespace:Rg.Plugins.Popup.Animations;assembly=Rg.Plugins.Popup"
xmlns:pages="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
xmlns:myAnimations="clr-namespace:StalizationApp.Animations;assembly=MyProject">
<StackLayout Margin="12"
Padding="24"
Spacing="24"
BackgroundColor="White"
HorizontalOptions="Center"
VerticalOptions="Center">
<StackLayout>
<Label Text="Login" />
<Entry FontSize="30"
Text="Email" />
</StackLayout>
<StackLayout>
<Label Text="Contraseña"/>
<Entry FontSize="30"
IsPassword="True"
Text="Contraseña" />
</StackLayout>
//enter code here
<Button BackgroundColor="DodgerBlue"
FontSize="30"
Text="Login"
TextColor="White" />
</StackLayout>
</pages:PopupPage>
Popuplogin.cs
using Rg.Plugins.Popup.Pages;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace SeralizationApp.Views
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class Popuplogin : PopupPage // ContentView
{
public Popuplogin ()
{
InitializeComponent ();
}
}
}

xamarin forms web view crashed

work with a web view however1 when I try to work with the web view
the page is crashed and get this error:
"An unhandled exception occured."
attaching my code:
also I want to know if I navagate with the web view to a Image
XAML:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="MashamApp.MImageEditor">
<ContentPage.Content>
<StackLayout>
<StackLayout Orientation="Horizontal" Padding="10,10">
<Button Text="Back" HorizontalOptions="StartAndExpand" Clicked="backClicked" />
<Button Text="Forward" HorizontalOptions="End" Clicked="forwardClicked" />
</StackLayout>
<WebView x:Name="Browser" WidthRequest="1000" HeightRequest="1000" />
</StackLayout>
</ContentPage.Content>
</ContentPage>
C#:
using Syncfusion.SfImageEditor.XForms;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace MashamApp
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MImageEditor : ContentPage
{
public MImageEditor()
{
InitializeComponent();
Browser.Source = "http://www.walla.co.il";
}
private void backClicked(object sender, EventArgs e)
{
// Check to see if there is anywhere to go back to
if (Browser.CanGoBack) {
Browser.GoBack ();
} else { // If not, leave the view
Navigation.PopAsync ();
}
}
private void forwardClicked(object sender, EventArgs e)
{
if (Browser.CanGoForward) {
Browser.GoForward ();
}
}
}
}

Background color of selecteditem in listview xamarin.forms

When working with ListView in Xamarin.forms, on selecting an item, the item remains like that with a rather ugly background colour. Can i disable this feature?
Here's my code:
<StackLayout>
<ListView x:Name="FoodList" HasUnevenRows="True" CachingStrategy="RecycleElement" ItemTapped="OnItemTapped">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="0,15,0,0" >
<StackLayout Orientation="Horizontal" BackgroundColor="White" >
<Image Source="{Binding image_url}" Aspect="AspectFill" HeightRequest="200" WidthRequest="200"/>
<StackLayout Orientation="Vertical">
<Label Text="{Binding food_name}" TextColor="Black" Style="{StaticResource MainLisTtext}" />
<Label Text="{Binding price}" TextColor="Black" Style="{StaticResource SubLisTtext}" />
<Label Text="{Binding food_description}" TextColor="Black" Style="{StaticResource SubLisTtext}" />
</StackLayout>
</StackLayout>
</StackLayout>
</ViewCell>vc
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>

This can be accomplished by using Custom Renderers
iOS Custom Renderer
Edit the SelectionStyle property on iOS.
Below is an example that sets the UITableViewCellSelectionStyle to None.
using System;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using ListViewSample.iOS;
[assembly: ExportRenderer(typeof(ViewCell), typeof(ViewCellItemSelectedCustomRenderer))]
namespace ListViewSample.iOS
{
public class ViewCellItemSelectedCustomRenderer : ViewCellRenderer
{
public override UITableViewCell GetCell(Cell item, UITableViewCell reusableCell, UITableView tv)
{
var cell = base.GetCell(item, reusableCell, tv);
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
return cell;
}
}
}
Android Custom Renderer
Create a new drawable, ViewCellBackground.xml and save it to the Resources>drawable folder:
<?xml version="1.0" encoding="UTF-8" ?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" >
<shape android:shape="rectangle">
<!--Change the selected color by modifying this hex value-->
<solid android:color="#FFFFFF" />
</shape>
</item>
<item>
<shape android:shape="rectangle">
<solid android:color="#FFFFFF" />
</shape>
</item>
</selector>
Create Custom Renderer for the ViewCell
using System;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using ListViewSample.Droid;
[assembly: ExportRenderer(typeof(ViewCell), typeof(ViewCellItemSelectedCustomRenderer))]
namespace ListViewSample.Droid
{
public class ViewCellItemSelectedCustomRenderer : ViewCellRenderer
{
protected override Android.Views.View GetCellCore(Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context)
{
var cell = base.GetCellCore(item, convertView, parent, context);
cell.SetBackgroundResource(Resource.Drawable.ViewCellBackground);
return cell;
}
}
}
Edit: Removed implementation without Custom Renderers
Sample Xamarin.Forms ListView App
using System;
using System.Collections.Generic;
using Xamarin.Forms;
namespace ListViewSample
{
public class CustomViewCell : ViewCell
{
public CustomViewCell()
{
View = new Label
{
Text = "Hello World"
};
}
}
public class ListViewContentPage : ContentPage
{
public ListViewContentPage()
{
var itemSourceList = new List<CustomViewCell>();
itemSourceList.Add(new CustomViewCell());
itemSourceList.Add(new CustomViewCell());
var listView = new ListView();
listView.ItemTemplate = new DataTemplate(typeof(CustomViewCell));
listView.ItemsSource = itemSourceList;
listView.SeparatorVisibility = SeparatorVisibility.None;
Content = listView;
}
}
public class App : Application
{
public App()
{
// The root page of your application
MainPage = new NavigationPage(new ListViewContentPage());
}
}
}

How to show data from ASP.NET Web Application to Xamarin.Forms?

I want all the records created in ASP.NET Web Application to be shown in my Mobile App Xamarin.Forms. What's happening to my program is that I was able to create records in my Web Application and save it, but I wasn't able to make it appear in my Xamarin.Forms Mobile app. I have created a MainViewModel that will get the records from the Web Application which I have binded to my MainPage.
These are my codes:
MainPageMain.xaml
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:XamarinDemoApp"
x:Class="XamarinDemoApp.MainPageMain"
xmlns:ViewModels="clr-namespace:XamarinDemoApp.ViewModels;assembly=XamarinDemoApp"
BackgroundColor="Teal"
Title=" Title Bar">
<ContentPage.BindingContext>
<ViewModels:MainViewModel/>
</ContentPage.BindingContext>
<StackLayout Orientation="Vertical">
<ListView ItemsSource="{Binding EmployeesList}"
HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal">
<Label Text="{Binding Name}"
FontSize="24"/>
<Label Text="{Binding Department}"
FontSize="24"/>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<Label Text="This is the MainPage"/>
</StackLayout>
MainViewModel.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;
using XamarinDemoApp.Models;
using XamarinDemoApp.Services;
namespace XamarinDemoApp.ViewModels
{
public class MainViewModel : INotifyPropertyChanged
{
private List<Employee> _employeesList;
public List<Employee> EmployeesList
{
get { return _employeesList; }
set
{
_employeesList = value;
OnPropertyChanged();
}
}
public MainViewModel()
{
InitializeDataAsync();
}
private async Task InitializeDataAsync()
{
var employeesServices = new EmployeesServices();
EmployeesList = await employeesServices.GetEmployeesAsync();
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
}

Make a separate API controller that you can use to call EmployeeList as a JSON object. That is the preferred way to do this kind of thing. Example:
public class EmployeeApiController : ApiController
{
[HttpGet]
public async Task<List<Employee>> Get()
{
return await employeesServices.GetEmployeesAsync();
}
}

Carousel - add different pages to Carousel

I am receiving an error - "Carousel has no children".
I utilized the carousel sample from Xamarin. Carousel works if the pages are the same. My requirement is that my pages are different but I want it to work in a carousel.
Page 1 - Image
Page 2 - Buttons
Page 3 - Check Boxes
MainPage.xaml
<?xml version="1.0" encoding="utf-8" ?>
<CarouselPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="CarouselApp.MainPage">
<CarouselPage.ItemTemplate>
<DataTemplate>
<ContentPage>
<ContentPage.Padding>
<OnPlatform x:TypeArguments="Thickness" iOS="0,40,0,0" Android="0,40,0,0">
</ContentPage.Padding>
<StackLayout>
<ContentView BindingContext="PageName"></ContentView>
</StackLayout>
</ContentPage>
</DataTemplate>
</CarouselPage.ItemTemplate>
</CarouselPage>
MainPage.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
namespace CarouselApp
{
public partial class MainPage : CarouselPage
{
public MainPage()
{
InitializeComponent();
ItemsSource = CarouselAppDataModel.All;
}
}
}
DataModel
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
namespace CarouselApp
{
public class CarouselDataModel : ContentView
{
public ContentView PageName { get; set; }
public static IList<CarouselDatModel> All { get; set; }
private Carousel03 fl3 as new Carousel03;
private Carousel04 fl4 as new Carousel04;
public CarouselDataDataModel()
{
All = new ObservableCollection<CarouselDataModel>
{
new CarouselDataModel
{
PageName = fl3
},
new CarouselDataModel
{
PageName = fl4
}
};
}
}
}

Since your pages are all different, and you are using XAML... rather than use a data template just create three consecutive content pages in your XAML as below
<CarouselPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="CarouselPageNavigation.MainPage">
<ContentPage>
<ContentPage.Padding>
<OnPlatform x:TypeArguments="Thickness" iOS="0,40,0,0" Android="0,40,0,0" />
</ContentPage.Padding>
<StackLayout>
<Label Text="Red" FontSize="Medium" HorizontalOptions="Center" />
<BoxView Color="Red" WidthRequest="200" HeightRequest="200" HorizontalOptions="Center" VerticalOptions="CenterAndExpand" />
</StackLayout>
</ContentPage>
<ContentPage>
...
</ContentPage>
<ContentPage>
...
</ContentPage>
</CarouselPage>