Xamarin Forms to Xamarin.Android - xamarin.forms

Question

I have some pages in Xamarin.Forms,since I need to build a custom camera,so I used Xamarin.Android.
now I need to go to Xamarin.Android/iOS from page of Xamarin.Forms and and back to Xamarin.Forms again. how can I do it?
pls help

Answer 1

You don't necessarily need to jump between Xamarin.Forms Views/Pages and Project Specific (iOS/Android) Views manually you can do it by using CustomRenderes which are part of Xamarin.Forms.
Basically you would create a Custom Page on Xamarin.Forms then specifying in each platform project how you want that page to look. You would attach this CustomRender to your Custom Page (the one you made in Xamarin.Forms) and the Framework would do the rest for you.
You can read about Custom Renderers here. And you can see a very similar example of what you are looking right in the Xamarin documentation here.
Hope this helps.-

Answer 2

Welcome to SO !
Baesd on a Xamarin Forms project , you can use Custom Renderer to achieve that .
Such as Creating the Custom Control :
public class CameraPreview : View
{
public static readonly BindableProperty CameraProperty = BindableProperty.Create (
propertyName: "Camera",
returnType: typeof(CameraOptions),
declaringType: typeof(CameraPreview),
defaultValue: CameraOptions.Rear);
public CameraOptions Camera {
get { return (CameraOptions)GetValue (CameraProperty); }
set { SetValue (CameraProperty, value); }
}
}
In Xaml :
<ContentPage ...
xmlns:local="clr-namespace:CustomRenderer;assembly=CustomRenderer"
...>
<ContentPage.Content>
<StackLayout>
<Label Text="Camera Preview:" />
<local:CameraPreview Camera="Rear"
HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" />
</StackLayout>
</ContentPage.Content>
</ContentPage>
Now you can create the Custom Renderer on each Platform.
Android :
[assembly: ExportRenderer(typeof(CustomRenderer.CameraPreview), typeof(CameraPreviewRenderer))]
namespace CustomRenderer.Droid
{
public class CameraPreviewRenderer : ViewRenderer<CustomRenderer.CameraPreview, CustomRenderer.Droid.CameraPreview>
{
CameraPreview cameraPreview;
public CameraPreviewRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<CustomRenderer.CameraPreview> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
// Unsubscribe
cameraPreview.Click -= OnCameraPreviewClicked;
}
if (e.NewElement != null)
{
if (Control == null)
{
cameraPreview = new CameraPreview(Context);
SetNativeControl(cameraPreview);
}
Control.Preview = Camera.Open((int)e.NewElement.Camera);
// Subscribe
cameraPreview.Click += OnCameraPreviewClicked;
}
}
void OnCameraPreviewClicked(object sender, EventArgs e)
{
if (cameraPreview.IsPreviewing)
{
cameraPreview.Preview.StopPreview();
cameraPreview.IsPreviewing = false;
}
else
{
cameraPreview.Preview.StartPreview();
cameraPreview.IsPreviewing = true;
}
}
...
}
}
iOS :
[assembly: ExportRenderer (typeof(CameraPreview), typeof(CameraPreviewRenderer))]
namespace CustomRenderer.iOS
{
public class CameraPreviewRenderer : ViewRenderer<CameraPreview, UICameraPreview>
{
UICameraPreview uiCameraPreview;
protected override void OnElementChanged (ElementChangedEventArgs<CameraPreview> e)
{
base.OnElementChanged (e);
if (e.OldElement != null) {
// Unsubscribe
uiCameraPreview.Tapped -= OnCameraPreviewTapped;
}
if (e.NewElement != null) {
if (Control == null) {
uiCameraPreview = new UICameraPreview (e.NewElement.Camera);
SetNativeControl (uiCameraPreview);
}
// Subscribe
uiCameraPreview.Tapped += OnCameraPreviewTapped;
}
}
void OnCameraPreviewTapped (object sender, EventArgs e)
{
if (uiCameraPreview.IsPreviewing) {
uiCameraPreview.CaptureSession.StopRunning ();
uiCameraPreview.IsPreviewing = false;
} else {
uiCameraPreview.CaptureSession.StartRunning ();
uiCameraPreview.IsPreviewing = true;
}
}
...
}
}
More info can refer to this official sample .