Using Layouts

The lay out process determines the position and size of the widgets. It depends on:

  • The layout of the containers: how the children are arranged within the containers.
  • The widgets content size: the size needed by the widgets for optimal display.

This process is started automatically when the desktop is shown. It can also be triggered programmatically.

Using a Flow Layout

The flow layout lays out any number of children horizontally or vertically, using multiple rows if necessary depending on the size of each child widget.

../../_images/flowexample.png

Creating a flow layout:

  • First, instantiate a Flow container, then add two Label objets to this container.
  • Finally, add the Flow container to the Desktop.
public static void main(String[] args) {
   MicroUI.start();
   Desktop desktop = new Desktop();
   Label label = new Label("Hello World");
   Label secondLabel = new Label("Hello World 2");

   Flow flowContainer = new Flow(LayoutOrientation.HORIZONTAL);
   flowContainer.addChild(label);
   flowContainer.addChild(secondLabel);

   desktop.setWidget(flowContainer);
   desktop.requestShow();
}

Both of the labels will share the screen:

../../_images/flowusage.png

Using a Canvas

A canvas lays out any number of children freely.

To add a widget to a Canvas, specify its position and size.

Note

Using Widget.NO_CONSTRAINT sets the width and height to the optimal size of the widget.

public static void main(String[] args) {
   MicroUI.start();
   Desktop desktop = new Desktop();
   Label label = new Label("Hello World");
   Label label2 = new Label("Hello World 2");

   Canvas canvas = new Canvas();
   canvas.addChild(label, 0, 0, Widget.NO_CONSTRAINT, Widget.NO_CONSTRAINT);
   canvas.addChild(label2, 15, 15, Widget.NO_CONSTRAINT, Widget.NO_CONSTRAINT);

   desktop.setWidget(canvas);
   desktop.requestShow();
}
../../_images/canvassample.png