Question

I have this button cell in my CellTable

ButtonCell reListCell = new ButtonCell();
reListColumn = new Column<EmployerJobs, String>(reListCell) {
  @Override
  public String getValue(EmployerJobs object) {
    return "ReList";
  }
};

ctJobs.addColumn(reListColumn, 
    EmployerDashBoardConstants.EMPTYHEADERCOLUMN);

but i only want this cell to be appear if the below condition pass

public void getDateDiff(final EmployerJobs object) {
  rpcService.getDateDiff(object.getJobValidDate(), new AsyncCallback<Boolean>() {
    public void onFailure(Throwable caught) {
    }

    public void onSuccess(Boolean jobExpired) {
      if(jobExpired) {
        // HERE I WANT TO SHOW MY RELISTCELL, means if the job is expired only then 
        // there will be a button showing relist would be appear in that row ,for 
        // the jobs which are not expired NO button should appear..  
      }
    }
  });
}

how can i achieve this?

thanks

Answer 1

I agree with DTing.
Quering the backend for each cell/row is not really efficient.
I would rather put the info (jobExpired) into your EmployerJobs class and transfer the info when you request the list of your EmployerJobs to be displayed in your CellTable.
You can update the list periodically to account for changes (see the expenses sample on how to do that).

But to your initial question (hiding the cell). There are two solutions:

• Use an ActionCell and override the render method.

ActionCell:

ActionCell<EmployerJobs> reListCell = new ActionCell<EmployerJobs>("ReList",
    new ActionCell.Delegate<EmployerJobs>() {
        @Override
        public void execute(EmployerJobs object) {
           // code to be executed 
        }
     }) 
 {
     @Override
     public void render(Cell.Context context,EmployerJobs value,SafeHtmlBuilder sb) {
         if (value.isJobExpired())   // isJobExpired returns the field jobExpired.
             super.render(context,value,sb);
         }
 };

 reListColumn = new Column<EmployerJobs, EmployerJobs>(reListCell) {
      @Override
      public String getValue(EmployerJobs object) {
        return object;
      }
 };

 ctJobs.addColumn(reListColumn, 
    EmployerDashBoardConstants.EMPTYHEADERCOLUMN);

• Use a ButtonCell and override the render method of your Column.

ButtonCell:

ButtonCell reListCell = new ButtonCell();
reListColumn = new Column<EmployerJobs, String>(reListCell) {
  @Override
  public String getValue(EmployerJobs object) {
    return "ReList";
  }
  @Override
  public void render(Cell.Context context,EmployerJobs object,SafeHtmlBuilder sb) {
     if (value.isJobExpired())   // isJobExpired returns the field jobExpired.
        super.render(context,value,sb);
  }
};

ctJobs.addColumn(reListColumn, 
    EmployerDashBoardConstants.EMPTYHEADERCOLUMN);