Grid layout in display

Hello all

I would like to use your collective wisdom to try to improve an aspect of a
program which is bugging me. The object is to present a summary of a lot of
detail from elsewhere in the app, and a convenient layout is a grid like a
spreadsheet - each column is a case, each row is an aspect of the cases.
Grid lines are not essential, and I can assume that all cell entries are
left justified. In some cases the cell entry is a summary, e.g. the number
of errors of a certain kind, and it would be handy to be able to hover or
click on the cell and get more detail.

So far I have a (more or less) working summary display, by using a
RichTextEdit and using tab stops to separate the columns. The problems are
that the entries are occasionally too long for a column width, so the next
column starts at the wrong tab, and I can't get the extra detail. I have
thought of three ways of improving the effect:

a. Draw the text of the entries directly on the display using
Canvas>>text:at:, which will ensure correct positioning but not give the
extra detail. The calculation of the cell locations looks unSmalltalkish
(like going back to my early days programming in Fortran), but it should
work.

b. Populate the pane with a grid of TextEdit subpanes, and enter the
contents of a cell in each subpane. I should be able to attach a tool tip
text to any subpane for the extra detail. It would be necessary to locate
and size the subpanes programmatically, and I am not sure how to do this.

c. Embed an Excel spreadsheet using ActiveX, and use cell comments for the
extra detail. I have never tried this, and I can't get the sample ActiveX
use of Excel in AXTypeLibraryAnalyzer class>>example3 to work, so I am a bit
apprehensive.

I would be grateful for any comments from the gurus in this group. If it's
documented somewhere that I haven't found, just give me pointers.

Thanks in advance

Peter Kenny

Peter,

> b. Populate the pane with a grid of TextEdit subpanes, and enter the
> contents of a cell in each subpane. I should be able to attach a tool tip
> text to any subpane for the extra detail. It would be necessary to locate
> and size the subpanes programmatically, and I am not sure how to do this.

If I understand you correctly there's a LayoutManager that will do most of
that for you.  As in

s := Shell show.
s view layoutManager: GridLayout new.
s view layoutManager
    rows: 5;
    columns: 3.
1 to: 5 do: [:r |
    1 to: 3 do: [:c |
        s view addSubView: (t := TextEdit new).
        t name: 'c' , c printString , 'r' , r printString]].

"later"

(s view viewNamed: 'c2r3') text: 'hello'

--
Ian

Use the Reply-To address to contact me.
Mail sent to the From address is ignored.

Peter,

> I would be grateful for any comments from the gurus in this group. If it's
> documented somewhere that I haven't found, just give me pointers.

I was wondering if a ListView might not also be a possible solution to this.
You couldn't use tool tip (they are broken in ListViews because of a Windows
bug) but perhaps, when the user selected a cell, you could display the extra
info in another text edit or on the StatusBar.

The only caveat might be that I can't recall how easy it is to get info on
which column is "selected" when the mouse is clicked. Anyone?

--
Ian

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Mail sent to the From address is ignored.

Ian

Many thanks for both ideas. i have been playing with the GridLayout
approach, and with a few tweaks I think I will get close to what I want. i
can see the idea of a multi-column ListView is attractive, and I may pursue
it later, but for the sake of getting something working quickly I shall
probably stick to GridLayout for now.

Looking again a the title of the post, I wonder why I ddn't think of
searching and finding it withoiut troubling the group. I suppose it's just
experience tells one how to search!

Thanks again

Peter

Ian, Peter,

> I was wondering if a ListView might not also be a possible solution to
> this.

Personally, I would try very hard to use this option in preference to drawing
my own graphics.  At least if there weren't too many columns.  It seems to be
feasible to use several tens of columns, e.g.

    p := ListPresenter
            show: 'Enhanced list view'
            on: (ListModel on: (1 to: 100)).
    99 timesRepeat: [p view addColumn].

> The only caveat might be that I can't recall how easy it is to get info on
> which column is "selected" when the mouse is clicked. Anyone?

I don't know of any easy way myself.  I note that the EditableListView does
this, and goes via the mouse position and a Window's hit-test (in
#fullItemFromPoint:, one of the loose methods it adds to ListView).

    -- chris

"Chris Uppal" <[hidden email]> wrote in message
news:421b4cbf$1$38041$[hidden email]...
> Ian, Peter,
>
> > I was wondering if a ListView might not also be a possible solution to
> > this.
>
> Personally, I would try very hard to use this option in preference to
drawing
> my own graphics.  At least if there weren't too many columns.

Chris

Thanks. In fact, after playing with a GridLayout of TextEdits for a while, I
have switched to the ListView approach, which seems to be working out. It
was a struggle to get the ListViewColumn>>getContentsBlock: method to
produce the effect I wanted - every column had the intended contents of the
last column. In the end I made the argument the result of applying Compiler
class>>evaluate: to the text of the block, but there must be an easier way.
However, I now have a way of making it work in a workspace, and today I
shall try to turn it into a method in my app. There will generally not be
more than a dozen or so columns, so it works OK from the space point of
view.
>
> > The only caveat might be that I can't recall how easy it is to get info
on
> > which column is "selected" when the mouse is clicked. Anyone?
>
> I don't know of any easy way myself.  I note that the EditableListView
does
> this, and goes via the mouse position and a Window's hit-test (in
> #fullItemFromPoint:, one of the loose methods it adds to ListView).
>
>     -- chris
>
I have been using the standard ListView so far, but I shall look at
EditableListView to see if I can make my method work more smoothly.

Peter

Peter>

> It was a struggle to get the
> ListViewColumn>>getContentsBlock: method to produce the effect I wanted -
> every column had the intended contents of the last column.

That sounds as if you are doing something roughly like:

    1 to: columns size do:
        [:i || block |
        block := [:row | row columnAt: i].
        (columns at: i) getContentsBlock: block].

which will have that effect.

It /should/ work, but doesn't (at least until D6 is released).  That's because
the way the block
    [:row | row columnAt: i]
is implemented -- it shares the 'i' variable with the containing method
invocation, rather than having its own private variable.  So as the loop
proceeds the value of 'i' is updated, but all the created blocks share access
to the /same/ 'i' variable.  The best (and cleanest) way to avoid the problem
is to create the block in a separate method:

    1 to: columns size do:
        [:i || block |
        block := self makeGetContentBlockForColumn: i.
        (columns at: i) getContentsBlock: block].

where:

    makeGetContentsBlockForColumn: anInteger
        ^ [:row | row columnAt: i]

This problem normally only occurs when you create several blocks in a loop (or
in some threading situations).

    -- chris

Chris

Thanks - it's good to know I am not a complete idiot. Your method may be a
cleaner fudge than mine, but it still looks like a fudge! I have a working
method now in my app, so all is well - and the suggestion of the ListView
was just right, so thanks again to you and Ian.

Peter