How to add Custom Components Preview?

Question

Android

I create my own custom component inherited from TextView

public class HelveticaTextView extends TextView {

  public HelveticaTextView(Context context) {
    super(context);
    setFont(context);
  }

  public HelveticaTextView(Context context, AttributeSet attributeSet) {
    super(context, attributeSet);
    setFont(context, attributeSet);
  }

  public HelveticaTextView(Context context, AttributeSet attributeSet,
      int defStyle) {
    super(context, attributeSet, defStyle);
    setFont(context, attributeSet);
  }

  private void setFont(Context context, AttributeSet attributeSet) {
    final String androidns = "http://schemas.android.com/apk/res/android";
    String textStyle = attributeSet.getAttributeValue(androidns,
        "textStyle");
    Typeface font = Typeface.createFromAsset(context.getAssets(),
        "helvetica.otf");
    if (textStyle != null) {
      if (textStyle.equals("0x1"))
        setTypeface(font, Typeface.BOLD);
      else if (textStyle.equals("italic"))
        setTypeface(font, Typeface.ITALIC);
      else
        setTypeface(font);
    } else
      setTypeface(font);
  }

  private void setFont(Context context) {
    Typeface font = Typeface.createFromAsset(context.getAssets(),
        "helvetica.otf");
    setTypeface(font);
  }
    
}

How to add a preview to a component so that the graphical editor displays an analogue of the parent (TextView), and not the path to the component class?
Thanks for the help.

Answer 1

Update the SDK, if there is a place)
View the error log and find out what the visual editor swears at, should write why it was not possible to create an instance of your view ... I
just created a custom textview and it is displayed perfectly in the editor ... maybe you have problems loading the font ...

Answer 2

title_with_back.xml: Typeface.createFromAsset() is not supported.
Just a problem with him. Is it possible to display a view from the parent class in the editor?