Custom View Not Working In AppCompatActivity

Question

Custom View Not Working In AppCompatActivity

Nathan Sokalski 4,111

I have a Xamarin.Android Class Library which contains a Custom View that inherits from GridLayout. I have used this Custom View many times with projects that inherit from Activity, but in my projects that inherit from AppCompatActivity I receive errors if attempting to use this Custom View. The error occurs on the following line in the OnCreate method of MainActivity:

this.SetContentView(Resource.Layout.activity_main);

The output window gives the following:

**Java.Lang.RuntimeException:** 'Binary XML file line #1 in com.companyname.itsabouttimeexperimental:layout/activity_main: Binary XML file line #1 in com.companyname.itsabouttimeexperimental:layout/mainscreenlayout: Error inflating class XamarinAndroidAppExtras.CircleButton'

(NOTE: activity_main is my main layout which uses an include that references mainscreenlayout, which is a GridLayout in a separate xml file, and XamarinAndroidAppExtras.CircleButton is my Custom View). The designer in Visual Studio 2022 displays my Custom View perfectly, it is not until I run the debugger that the error occurs. How can I figure out what needs changed in my Custom View to make it work in an AppCompatActivity?

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,151 Reputation points Microsoft External Staff

2022-11-29T09:17:57.037+00:00
There are many situations that can cause this problem, the most common being the following.

There is no default constructor defined for the inflate needs. public MyButton(Context context, IAttributeSet attrs) : base(context, attrs)
{
}

For custom views, there are misspellings in the name or path.

If your question is not related to the above reasons, could you please provide more detailed information about how to reproduce this issue?

Nathan Sokalski 4,111

I use the following constructors:

public CircleButton(Context context) : base(context) { this.Initialize(context); }  
public CircleButton(Context context, IAttributeSet attrs) : base(context, attrs) { this.Initialize(context, attrs); }  
public CircleButton(Context context, IAttributeSet attrs, int defstyleattrs) : base(context, attrs, defstyleattrs) { this.Initialize(context, attrs); }  
public CircleButton(Context context, IAttributeSet attrs, int defstyleattrs, int defstyleres) : base(context, attrs, defstyleattrs, defstyleres) { this.Initialize(context, attrs); }

Along with the following:

void Initialize(Context context, IAttributeSet attrs = null)  
{  
	Inflate(context, Resource.Layout.CircleButton, this);  
  
	//Obtain the button & text  
	Button btnCircleButton = FindViewById<Button>(Resource.Id.btnCircleButton);  
	TextView txtCircleButton = FindViewById<TextView>(Resource.Id.txtCircleButton);  
  
	if (attrs != null)  
	{  
		TypedArray ta = context.ObtainStyledAttributes(attrs, Resource.Styleable.CircleButton);  
		int CircleBorderThickness = ta.GetInt(Resource.Styleable.CircleButton_CircleBorderThickness, 3);  
		float CircleBorderRadius = ta.GetFloat(Resource.Styleable.CircleButton_CircleBorderRadius, 27);  
		//Code to set properties for btnCircleButton & txtCircleButton  
		ta.Recycle();  
	}  
}

I tried putting a breakpoint in Initialize, but it is never reached (not even the Inflate statement). I use the following XML:

<XamarinAndroidAppExtras.CircleButton/>

1 answer

Your answer

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,151 Reputation points Microsoft External Staff

2022-11-29T09:17:57.037+00:00

There are many situations that can cause this problem, the most common being the following.

There is no default constructor defined for the inflate needs. public MyButton(Context context, IAttributeSet attrs) : base(context, attrs)
{
}

For custom views, there are misspellings in the name or path.

If your question is not related to the above reasons, could you please provide more detailed information about how to reproduce this issue?
Nathan Sokalski 4,111 Reputation points

2022-11-29T19:12:15.447+00:00

I use the following constructors:

public CircleButton(Context context) : base(context) { this.Initialize(context); } public CircleButton(Context context, IAttributeSet attrs) : base(context, attrs) { this.Initialize(context, attrs); } public CircleButton(Context context, IAttributeSet attrs, int defstyleattrs) : base(context, attrs, defstyleattrs) { this.Initialize(context, attrs); } public CircleButton(Context context, IAttributeSet attrs, int defstyleattrs, int defstyleres) : base(context, attrs, defstyleattrs, defstyleres) { this.Initialize(context, attrs); }

Along with the following:

void Initialize(Context context, IAttributeSet attrs = null) { Inflate(context, Resource.Layout.CircleButton, this); //Obtain the button & text Button btnCircleButton = FindViewById<Button>(Resource.Id.btnCircleButton); TextView txtCircleButton = FindViewById<TextView>(Resource.Id.txtCircleButton); if (attrs != null) { TypedArray ta = context.ObtainStyledAttributes(attrs, Resource.Styleable.CircleButton); int CircleBorderThickness = ta.GetInt(Resource.Styleable.CircleButton_CircleBorderThickness, 3); float CircleBorderRadius = ta.GetFloat(Resource.Styleable.CircleButton_CircleBorderRadius, 27); //Code to set properties for btnCircleButton & txtCircleButton ta.Recycle(); } }

I tried putting a breakpoint in Initialize, but it is never reached (not even the Inflate statement). I use the following XML:

<XamarinAndroidAppExtras.CircleButton/>

Answer 1

Nathan Sokalski 4,111

I finally found the answer, and as in many cases, it was simple human error. When declaring the View in MainActivity, I was declaring it as a Button rather than the type of my Custom View (CircleButton). I appreciate your quick response, thanks!

Yonglun Liu (Shanghai Wicresoft Co,.Ltd.) 50,151 Reputation points Microsoft External Staff

2022-11-30T05:19:07.957+00:00

Thanks for your feedback.

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Custom View Not Working In AppCompatActivity

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