Add Help to Your Application/zh CN

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LCL增加了帮助系统,允许 为你的程序创建帮助.

快速开始

示例位置: examples/helphtml/.

演示如何使用HTML帮助控件。只需要拖拽它们到你的项目中。并设置并创建HTML文件。就可以给程序提供HelpKeyword。

如果要使用CHM帮助,请参照CHM帮助部分。

这里是一个非常好的演示 (chmdemo.zip): http://forum.lazarus.freepascal.org/index.php/topic,38487.msg261731.html#msg261731

帮助基础

LCL帮助包含两部分: 帮助数据库和查看器. 帮助数据库包含关键字 (ID, node, message, pascal, ...) 到帮助页面 (or help web site or...). 帮助查看器嗲用数据库向用户显示帮助信息.

  • A THelpDatabase manages content. It can be a collection of HTML pages or fpdoc XML files or a CHM file or a database or whatever.
  • A THelpViewer is a component that shows help content. For example a viewer for the mime type text/html can start a web browser.

When help is requested, the LCL queries each registered THelpDatabase and each database can return a list of entries. If several entries are returned, the LCL asks the user to choose an entry. Then the LCL asks the database to show the help for the entry. The database extracts the help content and asks the LCL for a viewer that supports the mime type of the content. Finally, the viewer shows the help content.

CHM

Context-sensitive CHM application help can be used from Lazarus 1.0 and later.

A demonstration program is included that shows how to include context-sensitive help using CHM and the lhelp CHM viewer (the same one that is used for IDE help by default). Please see ${lazarusdir}/components/chmhelp/democontrol/.

You can write your own CHM files, e.g. with the now ancient Microsoft HTML Workshop or with the new Lazarus chmmaker tools in $(lazarusdir)/tools/chmmaker You can use a TCHMHelpDatabase control like the THTMLHelpDatabase control described below.

The advantages of using the CHM system are a smaller, self contained help file instead of multiple files. On the other hand, not every system has a CHM viewer installed by default, so you might want to include lhelp, a CHM viewer written in Pascal and included with the Lazarus sources (components/chmhelp/lhelp/lhelp.lpi).

Using LHelp

  • Put a TLHelpConnector on your form.
  • Set LHelpPath with the name and location of the LHelp executable (this can be absolute, or relative to the application directory)
  • Set AutoRegister to true
// Example with both chm file and LHelp.exe in Application folder.
Procedure TForm1.FormCreate(Sender: TObject);
Begin
  If FileExists(ChangeFileExt(Application.ExeName, '.chm')) Then
  Begin
    CHMHelpDatabase1.Filename := ChangeFileExt(Application.ExeName, '.chm');
    CHMHelpDatabase1.Keyword := 'test';
    CHMHelpDatabase1.AutoRegister:=True;

    LHelpConnector1.LHelpPath := IncludeTrailingBackSlash(ExtractFileDir(Application.ExeName)) + 'lhelp.exe';
    LHelpConnector1.AutoRegister:=True;
  end
  Else
    mnuHelpMain.Enabled := False;
End; 

Procedure TForm1.Button1Click(Sender: TObject);
Begin
  If mnuHelpMain.Enabled Then  
    ShowHelpOrErrorForKeyword('','test/Main.html');
    //ShowTableOfContents;  (Not implemented for TCHMHelpDatabase)
End;


HTML

The LCL provides two components to use HTML files for help: THTMLHelpDatabase and THTMLBrowserHelpViewer. To see the HTML help, see the lazarus example examples/helphtml/htmlhelp1.lpi.

Setup HTML help for your application

Lazarus help items

Adding HTML help to your application is easy:

  • Put a THTMLHelpDatabase on a form.
  • Set AutoRegister to true.
  • Set KeywordPrefix to html/. It means all keywords must start with the string html/.
  • Set BaseURL to file://yourhelp/. This will search the HTML files in the sub folder yourhelp. You can specify full paths like file:///usr/lib/yourhelp/ or an URL like http://www.yoursite.com/.
  • Put a THTMLBrowserHelpViewer on the form. This component can start the user's default browser.
  • Set AutoRegister to true.

Creating a help entry

  • Now create the subfolder yourhelp and create a html page yourhelp/edit1.html. In case of a website, the help page should be accesible as http://www.yoursite.com/edit1.html
  • Put a TEdit on a form.
  • Set HelpType to htKeyword
  • Set HelpKeyword to html/edit1.html

When running the program you can focus the edit and press F1 to invoke the help. Under macOS the help key is Cmd-? (or Cmd+Shift+? depending on you keyboard layout). Note: Some window managers, widget set combinations do not pass F1 to the LCL.

INF (using fpGUI's DocView help viewer)

See the message and example project included in the Lazarus Forums. [1]

It shows a fully working example of an LCL application using fpGUI's DocView help viewer. It shows context sensitive help and general help.

For example:

  • Set focus to a specific control and press F1. It will show the help topic for that specific control.
  • Click the Help button and it will show the help topic for the dialog/form.
  • Select the "Help -> Show Help" menu item and it will show the general application help and display the first topic in the help file.

See also