Creating Widgets

  • To create a widget, we need to create a class that extends the Widget superclass.
  • In this example, we are going to create a simple progress bar.
  • So create a MyProgressBarWidget class extending Widget.

Note

The computeContentOptimalSize() and renderContent() methods must be overridden:

public class MyProgressBarWidget extends Widget {
   @Override
   protected void computeContentOptimalSize(Size size) {
      // TODO Auto-generated method stub
   }

   @Override
   protected void renderContent(GraphicsContext g, int contentWidth, int contentHeight) {
      // TODO Auto-generated method stub
   }
}

Setting Up

  • Let’s use a progress bar with a fixed size:

    protected void computeContentOptimalSize(Size size) {
       size.setSize(200,50);
    }
    
  • Then, let’s create the progress bar, first, it is important to add a progress value:

    private float progressValue;
    
  • Now, let’s render the progress bar:

    protected void renderContent(GraphicsContext g, int contentWidth, int contentHeight) {
       // Draws the remaining bar: a 1 px thick grey line, with 1px of fading.
       g.setColor(Colors.SILVER);
       int halfHeight = contentHeight / 2;
       ShapePainter.drawThickFadedLine(g, 0, halfHeight, contentWidth, halfHeight, 1, 1, Cap.ROUNDED, Cap.ROUNDED);
    
       // Draws the progress bar: a 3 px thick blue line, with 1px of fading.
       g.setColor(Colors.NAVY);
       int barWidth = (int) (contentWidth * this.progressValue);
       ShapePainter.drawThickFadedLine(g, 0, halfHeight, barWidth, halfHeight, 3, 1, Cap.ROUNDED, Cap.ROUNDED);
    }
    
  • Finally, let’s create a method to set the progress on the progress bar:

    public void setProgress(float progress) {
       this.progressValue = progress;
    }
    

Using with Animator

  • Using the code made in the previous Animation tutorial, doing the modifications below, it is now possible to see the progress bar animated:

    public static void main(String[] args) {
       MicroUI.start();
       Desktop desktop = new Desktop();
       final MyProgressBarWidget progressBar = new MyProgressBarWidget();
       Flow flow = new Flow(LayoutOrientation.VERTICAL);
       flow.addChild(progressBar);
    
       Animation progressBarAnimation = new Animation() {
    
          float progress;
    
          @Override
          public boolean tick(long currentTimeMillis) {
             this.progress += 0.001f;
             progressBar.setProgress(this.progress);
             progressBar.requestRender();
             return true;
          }
       };
       Animator animator = desktop.getAnimator();
       animator.startAnimation(progressBarAnimation);
       desktop.setWidget(flow);
       desktop.requestShow();
    }
    
    ../../_images/progressbar.png