Debug Utilities

A few utilities useful for debugging are available in the package ej.widget.util.debug of the widget library.

Print the Hierarchy of Widgets

The method HierarchyInspector.hierarchyToString(Widget) returns a String representing the hierarchy of a widget. In other words, it prints the widget and its children recursively in a tree format.

It may be used to analyse the content of a page and have a quick estimation of the number of widgets and the depth of the hierarchy.

For example:

Scroll
+--ScrollableList
|  +--Label
|  +--Dock
|  |  +--ImageWidget
|  |  +--Label
|  +--Label

The method HierarchyInspector.hierarchyStyleToString(Widget) returns the same information plus the list of the attributes of the style of each widget in the hierarchy. It only adds the attributes that differ from the default style.

For example:

Scroll (background=RectangularBackground, horizontalAlignment=hcenter)
+--ScrollableList (background=RectangularBackground)
|  +--Label (color=white, font=RasterFont[SourceSansPro_19px-300], horizontalAlignment=hcenter, verticalAlignment=vcenter)
|  +--Dock (background=NoBackground)
|  |  +--ImageWidget (horizontalAlignment=hcenter, verticalAlignment=vcenter)
|  |  +--Label (color=0xf8a331, font=RasterFont[SourceSansPro_19px-300], horizontalAlignment=hcenter, verticalAlignment=vcenter)
|  +--Label (color=white, font=RasterFont[SourceSansPro_19px-300], horizontalAlignment=hcenter, verticalAlignment=vcenter)

If the constant ej.mwt.debug.cascadingstyle.enabled is set (see this section), it will also print the selector that originated each style’s attribute.

For example:

Scroll (background=RectangularBackground from default, horizontalAlignment=hcenter from .class 896560)
+--ScrollableList (background=RectangularBackground from default)
|  +--Label (color=white from .class 896572, background=NoBackground from .class 896572, font=RasterFont[SourceSansPro_19px-300] from .class 896572, horizontalAlignment=hcenter from .class 896572, verticalAlignment=vcenter from .class 896572)
|  +--Dock (background=NoBackground from default)
|  |  +--ImageWidget (horizontalAlignment=hcenter from .class 896571, verticalAlignment=vcenter from .class 896571)
|  |  +--Label (color=0xf8a331 from .class 896572 and :nth-child(odd), font=RasterFont[SourceSansPro_19px-300] from .class 896572, horizontalAlignment=hcenter from .class 896572, verticalAlignment=vcenter from .class 896572)
|  +--Label (color=white from .class 896572, font=RasterFont[SourceSansPro_19px-300] from .class 896572, horizontalAlignment=hcenter from .class 896572, verticalAlignment=vcenter from .class 896572)

Print the Path to a Widget

The method HierarchyInspector.pathToWidgetToString(Widget) returns a String representing the list of ancestors of the widget. For example: Desktop > Scroll > ScrollableList > Label.

It may be used to identify a widget in a trace.

It is also possible to choose the separator by using HierarchyInspector.pathToWidgetToString(Widget, char) method. For example: Desktop ; Scroll ; ScrollableList ; Label.

Count the Number of Widgets or Containers

The methods HierarchyInspector.countNumberOfWidgets(Widget) and HierarchyInspector.countNumberOfContainers(Widget) respectively count the number of widgets and containers in a hierarchy.

It may be used to evaluate the complexity of a hierarchy of widgets.

Count the Maximum Depth of a Hierarchy

The method HierarchyInspector.countMaxDepth(Widget) counts the maximum depth of a hierarchy. In other words, the depth of the widget with the biggest number of parents recursively.

It may be used to evaluate the complexity of a hierarchy of widgets.

Print the Bounds of a Widget

The method BoundsInspector.boundsToString(Widget) returns a String with the widget type and its bounds. The returned String contains:

• the simple name of the class of the widget,

• its position relative to its parent,

• its size,

• its absolute position.

For example: Label: 0,0 7x25 (absolute: 75,75)

Print the bounds of all the widgets in a hierarchy

The method BoundsInspector.boundsRecursiveToString(Widget) returns a String representing the type and bounds of each widget in the hierarchy of a widget.

For example:

Scroll: 0,0 480x272 (absolute: 0,0)
+--ScrollableList: 0,0 480x272 (absolute: 0,0)
|  +--Label: 0,0 480x50 (absolute: 0,0)
|  +--Dock: 0,50 480x50 (absolute: 0,50)
|  |  +--ImageWidget: 0,0 70x50 (absolute: 0,50)
|  |  +--Label: 70,0 202x50 (absolute: 70,50)
|  +--Label: 0,100 480x50 (absolute: 0,100)