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androidx.camera.view.PreviewView Causes java.lang.NullPointerException in Xamarin.Android Designer

Nathan Sokalski 4,126 Reputation points
2022-08-24T19:35:36.773+00:00

I am working on adding an androidx.camera.view.PreviewView to my Xamarin.Android app, but it displays a java.lang.NullPointerException in the Xamarin.Android Designer in Visual Studio 2022. The Details: displayed in the Designer are as follows:

android.hardware.display.DisplayManager.registerDisplayListener(DisplayManager.java:414)
androidx.camera.view.PreviewView.startListeningToDisplayChange(PreviewView.java:970)
androidx.camera.view.PreviewView.onAttachedToWindow(PreviewView.java:299)
android.view.View.dispatchAttachedToWindow(View.java:18347)
android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3397)
android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3404)
android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3404)
android.view.ViewGroup.dispatchAttachedToWindow(ViewGroup.java:3404)
android.view.AttachInfo_Accessor.setAttachInfo(AttachInfo_Accessor.java:42)
com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:330)
com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:394)
com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:271)
mono.android.DesignerSession.loadInternal(DesignerSession.java:273)
mono.android.DesignerSession.lambda$load$0(DesignerSession.java:223)
mono.android.MonoDroidBroker.executeInMonoDroidContext(MonoDroidBroker.java:76)
mono.android.DesignerSession.load(DesignerSession.java:223)
mono.android.DesignerSession.processMessage(DesignerSession.java:676)
mono.android.MessageListener.executeMessage(MessageListener.java:88)
mono.android.MessageListener$Runner.run(MessageListener.java:44)
java.lang.Thread.run(Thread.java:748)

The exact xml of the PreviewView is as follows:

<androidx.camera.view.PreviewView android:id="@+id/pvCurrent" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_column="0" android:layout_row="0" tools:layout_width="match_parent" tools:layout_height="150dp" tools:background="@Color /Three"/>

I am not sure what to do, since this is my first time with PreviewView & it is a design time exception. What is the problem?

Xamarin
Xamarin
A Microsoft open-source app platform for building Android and iOS apps with .NET and C#.
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C#
C#
An object-oriented and type-safe programming language that has its roots in the C family of languages and includes support for component-oriented programming.
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1 answer

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  1. Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 38,446 Reputation points Microsoft Vendor
    2022-08-25T07:55:17.597+00:00

    Hello,

    There is an official sample for how to use androidx.camera.view.PreviewView in Xamarin.Android, please refer to Xamarin.CameraX1.

    It's Xamarin.Android version to implement the official Google guide of Getting Started with CameraX.

    Best Regards,

    Alec Liu.

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