Multiple Subreports Will Not Display

By: Bill Fritz - bfritz2
Multiple Subreports Will Not Display
2002-12-10 12:37
I submitted an incorrect xml on My Report Desin Question thread, I am restaing it here:
I am having trouble displaying subreports. The Master Report contains varying numbers of subreports each with its own datasource. There are two categories od subreports: 1) Plots - which only display an image; each plot/subreport should start on a new page and 2) Tables which can span multiple pages. There can be as many as 5-10 plots and a similar number of tables. IDo I use dummy droups to display these subreports and if so, one dummy group per subreport, or do I stuff all subreports into a summary section? I also am perplexed as to the guidelines of band height vs reportElement height for a subreport.

For example if I have a summary section, what should its band height be relative to its subreport reportElement heights? Her's an example of what I'm talking about. Can you do this? It doesn't seem to work. Does the Master report's band/subreport reportElement attributes: x, y, width, and height have to match what is actually specified in the Subreport.xml??? I don't know how Jasper Reports figures this all out, so am at a loss to get this working. By the way, thanks for all the help so far!!!

Bill

<summary>
<band height="60">
<subreport>
<reportElement x="0" y="0" width="515" height="20"/>
<subreportParameter name="Plot1Title">
<subreportParameterExpression>
$P{Plot1Title}
</subreportParameterExpression>
</subreportParameter>
<subreportParameter name="Plot1Image">
<subreportParameterExpression>
$P{Plot1Image}
</subreportParameterExpression>
</subreportParameter>
<dataSourceExpression>
new dori.jasper.engine.JREmptyDataSource()
</dataSourceExpression>
<subreportExpression class="java.lang.String">
"Plot1.jasper"
</subreportExpression>
</subreport>
<subreport>
<reportElement x="0" y="30" width="515" height="20"/>
<subreportParameter name="Plot1Title">
<subreportParameterExpression>
$P{Plot2Title}
</subreportParameterExpression>
</subreportParameter>
<subreportParameter name="Plot1Image">
<subreportParameterExpression>
$P{Plot2Image}
</subreportParameterExpression>
</subreportParameter>
<dataSourceExpression>
new dori.jasper.engine.JREmptyDataSource()
</dataSourceExpression>
<subreportExpression class="java.lang.String">
"Plot=2.jasper"
</subreportExpression>
</subreport>
</band>
</summary>




By: Teodor Danciu - teodord
RE: Multiple Subreports Will Not Display
2002-12-11 03:19

Hi,

Both solutions are correct.

The height of the subreport element represents
in fact its minimal height. This is because subreport
will almost certainly stretch. But their original height
is the minimum amont of space that they will surely
use from the band.

Lets say you have 5 subreports.
You could place all of them in one band (the summary of the master for example).
If each subreport has an original height of 20 and
there is no space between them, your fifth subreport
should be placed at y="80".
The problem with this approach is that when the
summary will overflow, the fifth subreport will overflow,
the engine will first try to place it at y=80 on the new page, will evaluate the space remaining until
the bottom of the page and only after will eliminate
the unused 80 pixels from the top of the page.
This means that you will surely get 80 pixels of unused space at the bottom of your fifth subreport.
See ?
To eliminate this 80 pixels high space at the bottom
of the page, you could make your subreports of height ="0" (they will stretch anyway) and place one
after the other, the next one pixel above the previous.
In this scenario, the fifth subreport will be placed at
y="4" and when it will overflow, the unwanted blank space at the end will be only 4 pixels high.

And now the other approach.
Make a dummy group for each subreport that you want to display. If you do so, you'll never have
problems with some white space left at the bottom
of your pages. And the height of the subreport does not matter, as I previously said. The band height
should exactly match the height of the subreport,
if you don't want to have extraspace between
subreports.

I hope this helps.
Teodor