Error inflating custom edit text

Question

I subclassed the standard EditText widget like so

public class MyEditText extends AppCompatEditText {

    public MyEditText( Context context )
    {
        super( context );
    }

    public MyEditText( Context context, AttributeSet attribute_set )
    {
        super( context, attribute_set );
    }

    public MyEditText( Context context, AttributeSet attribute_set, int def_style_attribute )
    {
        super( context, attribute_set, def_style_attribute );
    }

    @Override
    public boolean onKeyPreIme( int key_code, KeyEvent event )
    {
        if ( event.getKeyCode() == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_UP )
            this.clearFocus();

        return super.onKeyPreIme( key_code, event );
    }
} 

I declared this widget in my activity xml layout file like so

    <MyEditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:hint="[enter command here]"
        android:textColorHint="#5042f442"
        android:textSize="15dp"
        android:textColor="#42f442"
        android:background="#50000000"
        android:layout_alignParentBottom="true"
        android:gravity="center|left"
        android:paddingLeft="20dp"
        android:cursorVisible="false"
        />

</RelativeLayout>

When I install the apk to my phone and run the app I get this error

android.view.InflateException: Binary XML file line #7: Error inflating class MyEditText

Not sure why there is an error inflating the custom Edit Text.

Any idea why?

Thanks