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- Overview
- Implementation
- Including the files of the Java interface of WINDEV
- Loading the WINDEV library (WDL)
- Running WINDEV codes from the external language
- 1. Calling a WLanguage code
- 2. Retrieving the events triggered in the WINDEV windows
- Ending the application
External language: Programming in Java
We are going to call the elements developed in WINDEV (project, windows, analysis, ...) from the Java language. The WLanguage code used from the external language will be dynamically compiled and run during its call. This mode is illustrated by the City.JAVA project (in Java format) supplied in the "ExternalLanguages\Java" sub-directory of the setup directory of WINDEV. Remark: The Java language does not allow you to use the HyperFileSQL engine. To handle the HyperFileSQL engine, perform the necessary processes in WINDEV. Including the files of the Java interface of WINDEV The following file must be included in your Java code in order to call the WINDEV Java interface: WINDEV.CLASS (source code available in WINDEV.JAVA) The following lines must be found in the code of the main ".JAVA" file of your Java code:
public class city extends WINDEV
{
...
}
These lines allow you to retrieve the minimum declarations required to use the external interface. Remark: You can also call the methods of the WINDEV class by prefixing these methods by "WINDEV.". In this case, the previous code lines are not required. Loading the WINDEV library (WDL) The WINDEV library (.WDL extension) contains all the project elements (windows, reports, classes, queries, analysis, ...). Therefore, it must be loaded in memory in order for its components to be called. Caution: If the library to load contains windows, the code of each one of these windows must be included in the corresponding ".WDW" file ("Include the compiled code" must be checked in the "Details" tab of the description of each window).
/* Open the library */
/* if WDInt is not null, the library was not found! */
CALLWD("LIBRA,Disk,city.wdl");
/* equivalent to: WINDEV.CALLWD("LIBRA,Disk,city.wdl"); */
if (WDInt() == 0)
/* equivalent to: if (WINDEV.WDInt() == 0) */
{
...
else
{
/* Library not found */
CALLWD("Error, Library not found");
/* equivalent to: WINDEV.CALLWD("Error, Library not found"); */
}
Running WINDEV codes from the external language 1. Calling a WLanguage code All the WLanguage functions can be called from the external language. The behavior of these WLanguage functions as well as the returned values are identical whether they are called: - from WINDEV or
- from the interface of external language
To find out the parameters and the return values of a WLanguage function, see the online help or the documentation about WLanguage. The call to a WLanguage procedure from the external interface is performed by CallWD. For example:
/* open the first window of the program that contains the menu */
CALLWD("Open,menufc.wdw");
/* equivalent to: WINDEV.CALLWD("OPEN,menufc.wdw"); */
2. Retrieving the events triggered in the WINDEV windows The input in the WINDEV windows requires to retrieve the events triggered in these windows. To retrieve the user events (click on a menu, on a button, ...), you must implement a system based on a loop in your Java program. This loop will remain active as long as the WINDEV window is opened and it will be used to intercept each user action. To find out the type of action performed by the user, you have the ability to use a character string variable (in WLanguage) named 'WDKey'. This variable will be used in your WLanguage code to signal to the Java program which button was pressed for example. Example: Java code
/* open the first window of the program that contains the menu */
CALLWD("Open,menufc.wdw");
/* the program loops until the File Exit option
is selected */
boolean bInput = true;
while (bInput)
{
/* perform the input of the menu */
CALLWD("Screen,Input");
/* the status report WDKey is set to *M* when a menu choice
was selected */
if (WDKey().equals ("*M*"))
{
...
}
}
CALLWD("CLOSE");
Code for intercepting the selection of "File..Exit" of the WINDEV "Menu" window:
String szOption = WDKey();
if (szOption.equals("FQ"))
{
bInput = false;
}
When the user clicks "File .. Exit": - WDKey will return "*M*".
- WDString will return the shortcut letters in the order in which the menus are selected. In our example, WDString returns "FE".
To end the use of external interface, type the following code lines:
/* Done... */
WDEnd();
/* equivalent to: WINDEV.WDEnd(); */
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