Wednesday 21 September 2016

Show report tooltip as notification

Last week I described a method to make the tooltip on information more accessible to the end user.

Here is how you could make the same information available to touchscreen users.

1) First step, as before, is to define the HTML Expression of the column to include the title tag.
In this case I also stored my row identifier as an extra data- attribute.
<span title="#RECENT_NOTE#" data-key="#ROW_KEY#">#MY_COLUMN#</span>

2a) Create a dynamic action on click of the column cell.
jQuery Selector:

2b) Set the value of a hidden page item.
This could be done a few ways, but here is how you can do it with Set Value, based on a JavaScript expression.
Set Value action example

What's pertinent is this.triggeringElement, which identifies the element being clicked. In this case it's the table cell, so .children() identifies the span from the HTML expression; .data() grabs the extra attribute; and .attr() grabs the title tooltip.
$(this.triggeringElement).children('span').data('key') + ': ' + $(this.triggeringElement).attr('title')

This expression extracts the a relevant key value (to identify the record) and concatenates it with the tooltip.

My P50_LAST_NOTE is hidden and unprotected.

2c) A Notification plugin could be used to display the value set in the hidden item, as a second action in the dynamic action. Other notification plugins are also available.
This 'gritter' style notification from APEX uses the hash syntax to get the client value,
As opposed to the value from session state while the page was rendered.
This information is documented in the relevant attribute help.

Now when you tap (or click) on the cell, the tooltip is displayed in the notification.

Wednesday 14 September 2016

Extend column tooltip to table cell

Quite sometime ago while still on 3.x I described a simple way to add tooltips in a report using standard HTML in a HTML Expression.
<span title="#RECENT_NOTE#">#MY_COLUMN#</span>

However, it will only appear when hovering over the span content, not anywhere within the table cell.

To do so we can add a dynamic action to execute some JavaScript after refresh of the relevant region.
$('td[headers=my_column] span').each( // for every data cell in the column
  function() { 
     // copy the title attribute to the parent cell
$(this).parent().attr('title',  $(this).attr('title'));
This JavaScript copies the title attribute from the inner span to the surrounding td tag, so you will see the tooltip when the cursor is anywhere within the cell. I find this relevant when there is a bit of spacing/padding in the report.

In this follow-up post I describe how you could display this tooltip on tap of the cell, useful when used within touch devices.

Friday 9 September 2016

APEX Survey Results: Workspace Activity Log

This question in my 2015 survey relates to built-in instrumentation.

Q7. Do you utilise apex_workspace_activity_log (for monitoring/reporting application usage)?

Yes (90)  47%
No (102) 53%

This log table reports details of all page rendering and AJAX process calls. I really like this information, though I would like to be able to add to the output things such as
sys_context('userenv', 'server_host')

In addition to the Monitoring pages you'll find in the APEX administration section, I've built a few pages that report on this information in my own particular way. This allows me to monitor behaviour and identify bottlenecks. More information to come on this since it's fuelling a presentation I'm writing on charting in APEX 5.1, so stay tuned.

Monday 5 September 2016

Users still double click buttons

Despite web pages having been around for quite some time, and users have been given years of affordance, people still double click on links & buttons in web pages.

This can cause a few issues in an APEX environment as the underlying process may get executed twice, and today I came up with what I thought was a simple, declarative solution.

In my case I had a button that submitted a modal page. I added a dynamic action that simply hid the button on click. I just had to ensure the action didn't execute on page load, and the button still submitted the page.

I thought I'd look around to see what others have done to mitigate this issue, and it seems I was on par, but with less code:

Wonderfully verbose description of what I described above
Funky JavaScript solution from 4.x
JavaScript solution in 3.x
Similar JavaScript solution
Purely session state protection

The only thing that makes me uncomfortable about my suggestion is the button has two behaviours, so Roeland's description may be considered more elegant, ie - a submit and hide action.

Friday 2 September 2016

APEX Survey Results: Instrumentation / Debugging

This question from my 2015 survey may pique curiosity among some APEX developers.

Q6: How do you instrument your code?

Hopefully those in the 22% who do not add instrumentation just didn't understand the question.

Instrumentation is another term for adding debugging information to your code. There is plenty of commentary on this topic and done right it can make tracking down problems a breeze.

It can be as simple as knowing when a procedure was called, and with what parameters. Take the following procedure definition with instrumentation (debug logs) added.
procedure xyz(p_in number) is
  debug('start xyz');

  -- do stuff

  debug('end xyz');
 I think you're essentially coding blindfolded without it. You could only infer this procedure was executed because of whatever it does, and if something goes wrong how do you know what was passed in? Where did it get up to? Did it execute at all?

Imagine using the database without the ALL% dictionary views. They're essentially instrumentation to your database. Tom Kyte has some particularly good talks on the topic, and a few chapters in his various books.

It's very much a PL/SQL thing, but since APEX pages are generated via PL/SQL, there is a natural solution with the supplied apex_debug package. Any process can add information to the APEX debug log, which is only collected while debug is on.

There is no reason why you shouldn't instrument any PL/SQL, and have the granular control to turn on/off at will. Libraries are available to make this job easier.

You may have heard Logger talked about at conferences. It's a community developed library, well, mostly driven by some key players. It's had a few homes (remember google code?) but is now found on GitHub:

PL/SQL Logger can be found here, if you want to compare solutions or look for ideas, read other people's PL/SQL.

Despite recommending it a few times, I've never actually used Logger on-site (sorry Martin). For quite some time I've had a basic infrastructure of my own that has worked fine, using the same premise. That being said, it's on my list to convert/upgrade when the timing is right. Partially because I've followed it's progress, know who wrote it, and inspected the code. I look forward to benefits some extra features will bring.

The next few questions also relate to instrumentation, so stay tuned.