| 1 | How to Write, Compile and Execute a SWT Application |
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| 2 | =================================================== |
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| 3 | =================================================== |
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| 4 | |
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| 5 | |
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| 6 | Introduction |
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| 7 | ============ |
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| 8 | |
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| 9 | I have spent today looking at SWT and Eclipse as potential |
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| 10 | technologies for WCKER's implementation. |
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| 11 | |
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| 12 | SWT is a replacement GUI API for Java (instead of the usual |
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| 13 | AWT/Swing) and Eclipse is an integrated IDE for Java development |
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| 14 | which can also do CVS stuff. |
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| 15 | |
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| 16 | For "looking at", read "trying to get to work" ! :-) |
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| 17 | I didn't help that the instructions in the online tutorials |
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| 18 | are wrong, and the standard tutorial example does not itself |
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| 19 | work. Finally, I managed to find an online forum where some |
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| 20 | of these issues were discussed ..... phew!!!!!! |
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| 21 | |
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| 22 | The next section documents my hard-won findings of how to |
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| 23 | produce a working SWT application. |
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| 24 | |
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| 25 | |
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| 26 | Developing a SWT application |
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| 27 | ============================ |
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| 28 | |
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| 29 | Source Code |
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| 30 | ----------- |
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| 31 | |
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| 32 | import org.eclipse.swt.widgets.*; |
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| 33 | import org.eclipse.swt.*; |
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| 34 | /**/ |
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| 35 | public class SWTHello { |
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| 36 | public static void main(String[] args) { |
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| 37 | |
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| 38 | MessageBox m = new MessageBox(new Shell()); |
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| 39 | m.setMessage("Hello, World"); |
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| 40 | m.open(); |
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| 41 | } |
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| 42 | } |
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| 43 | |
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| 44 | Compilation |
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| 45 | ----------- |
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| 46 | |
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| 47 | javac -classpath /usr/eclipse/eclipse/plugins/org.eclipse.swt.gtk_3.0.1/ws/gtk/swt.jar:/usr/eclipse/eclipse/plugins/org.eclipse.swt.gtk_3.0.1/ws/gtk/swt-pi.jar SWTHello.java |
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| 48 | |
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| 49 | Notes: |
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| 50 | (1) Only one of the two necessary JAR files was mentioned in the tutorials. |
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| 51 | (2) /usr/eclipse is the local installation root of Eclipse |
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| 52 | (3) It is also possible to supply these command line arguments through |
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| 53 | the CLASSPATH environment variable. |
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| 54 | |
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| 55 | Execution |
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| 56 | --------- |
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| 57 | |
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| 58 | java -classpath /usr/eclipse/eclipse/plugins/org.eclipse.swt.gtk_3.0.1/ws/gtk/swt.jar:/usr/eclipse/eclipse/plugins/org.eclipse.swt.gtk_3.0.1/ws/gtk/swt-pi.jar:. -Djava.library.path=/usr/eclipse/eclipse/plugins/org.eclipse.swt.gtk_3.0.1/os/linux/x86/ SWTHello |
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| 59 | |
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| 60 | Note: |
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| 61 | |
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| 62 | (1) As SWT also uses a native (i.e. 'C') library, then one has to not only specify where Java |
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| 63 | objects can be found but also 'C' objects i.e. more variables to get wrong. |
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| 64 | |
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| 65 | (2) It is also possible to supply these command line arguments through |
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| 66 | the CLASSPATH and LD_LIBRARY_PATH environment variables. |
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| 67 | |
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| 68 | |
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| 69 | Conclusion |
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| 70 | ========== |
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| 71 | |
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| 72 | I am able now to build and run small SWT applications, both inside and outside the |
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| 73 | Eclipse IDE. Only the command-line solutions are provided for succinctness. The next |
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| 74 | stage is to assess the ease of implementing some initial WCKER pages in SWT. |
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| 75 | |
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| 76 | Eclipse also contains an interactive graphical Java debugger (to be checked out): this is |
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| 77 | particularly good news (fingers crossed) as the stand-alone Java debuggers I tried out earlier |
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| 78 | in the project were universally poor! |
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| 79 | |
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| 80 | |
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| 81 | David |
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