Custom ImageView crashes program

Question

I am making a small app for Android, where I have a RelativeLayout, which amongst other things contains a custom ImageView. In my Java code I have this class:

package com.example.android.helloactivity;


class ArrowImageView extends ImageView {
    public ArrowImageView(Context context) {
        super(context);
    }
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(10,10,10,null);
    }
}

Then in my RelativeLayout xml I have the following:

<RelativeLayout android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="vertical"
            android:background="#FFF"
            xmlns:android="http://schemas.android.com/apk/res/android">
    <Button ...... />
    <TextView ......./>

    <com.example.android.helloactivity.ArrowImageView
        android:id="@+id/hello_activity_bearingarrow"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</RelativeLayout>

When I run my main class (not shown here) then my program crashes. If I omit the xml reference to ArrowImageView, then it does not crash.

Am I referring to my custom class te wrong way, or what is going on?

Answer 1

When extending the View widgets, if you plan to use them in XML layouts you need to also override the constructors that take the AttributeSet argument.