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--- en:gui-usage [2015/01/01 17:23] – [JScrollBar] roehner
+++ en:gui-usage [2015/01/02 12:40] – [JMenu] roehner
@@ Zeile 185: / Zeile 185: @@
 A JScrollPane-component provides a horizontal and a vertical JScrollBar-component for a twodimensional scrolling.
 The Java-Editor adds to JTextArea, JList, JTable, JTree, JEditorPane und JTextPane-components automatically a JScrollPane-component.
+\\
+----
+==== JPanel ====
+{{:de:panel.png}}
+JPanel-components are used for structuring of graphical user interfaces. Each JPanel-component is a container which can hold other gui-components. With the object-inspector you can set a border to a JPanel-component.
+\\
+----
+==== Canvas ====
+{{:de:canvas.png}}
+A Canvas-component provides a drawing-area.
+To draw on the drawing-area you can get a graphic-context from the Canvas-component. This graphic-context is used as a paint-box with many drawing-possibilities.
+You get the graphics-context from your Canvas-component in this way:
+<code java>  Graphics g = myCanvas.getGraphics();</code>
+With the graphics-context you are able to draw e. g. a rectangle:
+<code java>  g.fillRect(100, 50, 200, 250);</code>
+If you minimize your Java-Application with a Canvas-component und show it up again, the content of the Canvas-Component is lost. To avoid this, you have to create a subclass from Canvas and do the drawing in the //paint(Graphics g)// method. Such a derived class can be placed in a GUI-form with right-click on the Canvas-Symbol.
+The turtle which belongs to the Java-Editor is an example of a Canvas-subclass.\\
+----
+==== Turtle ====
+{{:de:turtle.png}}
+The Turtle-component provides a drawing-area, on which you can draw with turtle-commands. You find them in the documentation of the Turtle-class.
+As a didactic reduction the turtle has a //setOrigin(double x, double y)-method//, with which you can define a coordinatesystem as known from mathematics.
+Example:
+{{:de:turtlesetorigin.png}}
+The Turtle and it's documentation must be installed inside des Java-Editor configuration.
+\\
+----
+==== JMenuBar ====
+{{:de:menubardemo.png}}
+With a JMenuBar-component you can create a menu bar. The configuration is done via the menus (JMenu-components)
+to be displayed in the menu bar.
+\\
+----
+==== JMenu ====
+{{:de:jmenudemo.png}}
+With a JMenu-component you create a menu for a menu bar. In the object-inspector you specify the desired menu bar at the //MenuBar// attribute, the menu commands (e. g. New, Open, Save, Print, Exit) at the //MenuItems// attribute and the caption of the menu (e. g. File) in the menu bar at the //Text// attribute.
+For each menu command the Java-Editor creates a corresponding event method.
+\\
+----
+==== JPopupMenu ====
+{{:de:jpopupmenudemo.png}}
+With a JPopupMenu-component you create a popup menu. In the example a canvas component with yellow background reacts on a rightclick and shows the popup menu.
+{{:en:jpopupmenudemo2.png}}
+In the object inspector you input at the attribute //Listener// the gui-component, which shows the popup menu when rightcklicked. By the default //this// the background of the application window recacts on a rightclick. At the attribute //MenuItems// you input the menu commands (e. g. Clear, Draw, Print). Usually the attribute //Text// as label of a popup menu isn't shown.
+For each menu command the Java-Editor creates a corresponding event method.
+\\
+----
 ==== JTable ====
 {{:en:jtableicon.png}} With a jTable-component you display a table.