Question

I’m new to Qooxdoo (i’m using version 0.7.4, because I’m using Eclipse RAP) and I’m try to create a Custom Widget based on CanvasLayout class, that composites another Widgets. Here little peace of code:

qx.Class.define( "my.CanvasWidget", {
  extend: qx.ui.layout.CanvasLayout,
   construct: function( id ) {
     this.base( arguments );
     ...
   }

    }
  } );


//If using:

var myCanvasWidget = new my.CanvasWidget("myId");
...
myCanvasWidget.setBackgroundColor("#ff0000");

My question is: the setBackgroundColor has no effort on myCanvasWidget, why is it so (The property backgroundColor exist in super Class “Widget”)?

Answer 1

It depends on the size of your CanvasLayout widget. Setting the size (height and width) of it will show you the background color.

 // in the constructor of your widget
 this.setWidth(100);  // 100 for example
 this.setHeight(100);

As it is 0.7.x, the size information, as far as I know, will not be calculated automatically so you have to take care of that yourself.