Creating your own Widget class

You can create your own widget by extending the Widget class

public class MyWidget extends Widget
{
   /**
     * Constructs a Widget object.
     *
     * @param client The Minecraft client instance
     */
    public MyWidget(MinecraftClient client, <Other Parameters>) {
        super(client);
    }

    @Override
    public WidgetBox getWidgetBox() {
        // x1,y1,x2,y2 are used to define the box around the widget
        // scale variable to use the value from user or set your own scale
        return new WidgetBox(x1,y1,x2,y2,scale);
    }

    @Override
    public void render(DrawContext drawContext) {

    }
}

You can render whatever you want within the render() method

getWidgetBox() is used to define a widgetBox which the player can use to move or interact with.

You can use this to add a widget using: Widgets.

If you want to save and load this widget then you can add the following:

private String value = "V";
private String key = "Key";
@Override
public void writeToTag(NbtCompound tag) {
    super.writeToTag(tag);
    tag.putString(key, value);
}

@Override
public void readFromTag(NbtCompound tag) {
    super.readFromTag(tag);
    value = tag.getString(key /* Or "Key"*/);
}

To save and load this Widget, you can implement the WidgetLoading class in your main class:

public class MyMainClass implements ClientModInitializer,WidgetLoading {
   private DynamicUtil dynamicutil;
     @Override
    public void onInitializeClient() {
      dynamicutil=DynamicHUD.getDynamicUtil();
      DynamicHUD.setIWigdets(new MyClass());
      dynamicutil.getWidgetManager().setWidgetLoading(new MyMainClass());
   }
    @Override
    public Widget loadWidgetsFromTag(String className, NbtCompound widgetTag) {
        //SAMPLE CODE EXAMPLE :
        if (className.equals(MyWidget.class.getName())) {
            MyWidget widget = new MyWidget (MinecraftClient.getInstance(),<Other parameters>);
            widget.readFromTag(widgetTag);
            return widget;
        }
        return WidgetLoading.super.loadWidgetsFromTag(className, widgetTag);
    }
}

Using this code, we get the className from the load file of the widgets and using that we determine if the widget is of MyWidget class. If it is then we create a new widget whose parameter values are changed by reading the widget save data ( i.e, xpercent, yPercent, enabled, etc.)

Now set the MyMainClass as widgetLoading so that it is registered during loading or saving:

dynamicutil.getWidgetManager().setWidgetLoading(new MyMainClass());