Blog about (Web-) Programming, Graphics and Games.


Blog/Diary concept, notes on JEditorPane

For notes on projects and other stuff I'm working on a blog/diary application. As other blogs the app maintains entries, that can be marked with tags. In the following some concepts are described.
  • 2 Renderers. Currently the blog has 2 renderers, which display the entries. Both are written in Java. The first ([1] in the picture) is completely self-written. Thus arbitrary concepts can be tested with this renderer, e.g. taglines (more about that below). The second renderer ([2] in the picture) uses html, which is displayed with the Java html component JEditorPane. This html frontend might be a starting point for a later online version of the blog.
  • Sticky tags. For todo lists or important stuff to be rememberered always there are sticky entries ([3] in the picture). They are implemented using a 'Sticky' tag. The blog renderer draws all entries with a 'Sticky' tag highlighted and on top of other entries.
  • Checkboxes. For todo-lists checkboxes in entries might be useful, that can be checked if a task is done ([4] in the picture). In this app checkboxes are implemented in the following way: The texts "[_]" and "[X]" within an entry make the blog-app render a unchecked/checked checkbox at this position within the text. If the checkbox is clicked the entry text is changed, "[_]" is replaced by "[X]", and a timestamp is added to the text. Clicking a checkbox thus is a special way of editing an entry. If the entry has a 'Todo' tag and if with a checkbox click all checkboxes of the entry are checked, the entry automatically looses the 'Todo' tag.
  • Taglines. To visually distinguish entries of different topics (with different tags) there are taglines ([5] in the picture). This are lines between entries of specific tags with a special color for each tag. The tag-text is drawn besides the entry with the same color. The lines blend out if they are drawn behind entries that dont carry the tag of the line. An older version of taglines is described in this previous blogpost.
Some general notes on JEditorPane: This component is a part of the quite old Java Swing Api, hasnt changed in years and only supports Html 3.2. Nevertheless imho its a very useful lightweight html renderer (opposed to gecko/webkit bindings), useful for structured/formatted output or to render complex gui layouts. The standard approach to Gui layouts, LayoutManagers, is probably hard to implemented for this blog layout, with lots fonts, floating texts and tables.
JEditor renders html-checkboxes as Swing component JCheckbox. This checkboxes can be accessed via jEditorPane.getComponent(i). This will return a java.awt.Container whose first component is the checkbox:
JCheckbox jcb=(JCheckbox)((Container)jEditorPane.getComponent(i)).getComponent(0);
Now eg. listeners can be added to the Checkbox, that inform, if it is clicked. Following link helped to figure out checkbox access:

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