gpollice

POSSE Day 3: Taking the measure of Measure

In OpenSource on June 9, 2010 at 11:04 pm

So today we started work on the Measure Activity. It certainly needs work. The idea behind Measure is really nice. The user can use a sensor or the microphone and capture data from them. The actual data is written to the journal, probably not in the best way, but it’s there. The data can be imported into other applications for analysis.

My partner, Mihaela and I started working on ticket 1911 from the Sugar bug tracker. There are several problems we uncovered while trying to understand the code enough to reproduce the original problem and understand what the application was trying to do. Here are the things we discovered.

  • The pull down that shows “Now”, coupled with the button whose tool tip says “Start Recording” are terribly misleading It implies, as the author of the ticket seems to have understood, that the Measure will begin recording data when you press the button and stop recording automatically when the specified time ends. In fact, the time is the interval between samples and this goes on until press the button again.
  • Once you realize that the interval is correct, it actually doesn’t represent the right amount of time between snapshots. The code uses a counter and the counts are wrong. This may be due to different processor or microphone sensing rates.
  • The tool tips are quite misleading and do not exist on all of the controls on the toolbar.
  • The behavior of Measure is rather fragile. We had it crash a couple of times for no obvious reason. It also hung after we put in a debug statement, but then when we brought it back up, it worked fine. Also, when we tried to quit, the Activity asked if we wanted to keep (the entries?) it came up with a “Keep error.” This too went away mysteriously. But that’s for another day.

We’ve made quite a few changes. We added appropriate tool tips to the combo box that contains the sampling interval and to the button that starts and stops the sampling. We also changed the text in the combo box to be more descriptive and removed the choice that did nothing. Next we tackle the harder problem of controlling the timing for taking the snapshots into a timing thread.

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