Jface tableviewer multi sort columns

Question

dear all,

i am implementing a tableviewer that is able to sort values depengin on their column order. e.g. column1-column2-columnX sorts the rows first on the values of column 1, then column 2, column....

Therefore i want to use a ColumnViewerSorter, especially the method "int doCompare(Viewer viewer, Object e1, Object e2);"

inside this method i want to sort depending on other Tableviewer Row/Cells for comparison and the difficulty is that JFace tableviewer does the sort in the view only, so i have to "ask" the tableviewer itself for the actual value of e.g. "column 1, row 20"

using the function "viewer.getElementAt(index)" inside "docompare" wold be ok, but inside docompare i do have no reference to the objects e1 and e2 position in the tableviewer.

how could i achieve that?

thanking you very much in advance for helping me

best regards,

Malcom

Answer 1

You could iterate through all items in the table viewer and see where the objects e1 and e2 are, of course.

BUT... and I hope I understand your problem correcly... why do you want to implement multisorting? Let's say you have 3 coluns:

Col1      Col2      Col3
-------------------------
 a2        b1        c4   
 a1        b2        c1
 a2        b1        c3

To obtain the sorting order Col1-Col2-Col3, the user can click on Col3, then on Col2, and in the end Col1:

Col1      Col2     _Col3_
-------------------------
 a1        b2        c1        
 a2        b1        c3
 a2        b1        c4


Col1     _Col2_     Col3
-------------------------     
 a2        b1        c3   
 a2        b1        c4
 a1        b2        c1


_Col1_     Col2     Col3
-------------------------     
 a1        b2        c1     
 a2        b1        c3   
 a2        b1        c4

This might not be the best example, but to obtain "multi sorting", the user just has to sort the desired columns in the opposite order.