MAP524/DPS924 - 2014

Learning goes on after leaving classrooms and computer labs.Let us use this wiki to do collaborative learning and share our excitement and headaches in developing Android applications. Feel free to create new and interesting topics on this wiki page.

Android Discovery Zone

In Lab2, when I was modifying and saving FirstActivity.java.bak while using NLED, the editor automatically saved a FirstActivity.java.bak in the same folder. When running 'ant debug' to compile, it generated error, explaining that unauthorized file was contained in the source folder. The way to solve this issue is to simply remove the .bak file or any other file extensions that is not the .java extension in the source directory. -- Peter

Labs Q&A Fall 2013

• Has anyone run into a problem where the emulator refuses to rotate (at all, never mind the layout of the running app)? I tried Ctrl+f11/f12, f11/f12, but none of them work. And I don't have a number pad on my laptop to try 7/9. --Andrew
  • I pressed the HOME key (number pad) on my laptop and the emulator's orientation changed from portrait to landscape. (Peter)
    • Figured it out - it was already used by the xfce window manager to switch to desktop 11/12, just cleared that binding and now it works as it should with the emulator. --Andrew

• If my app has an activity (activity1) that starts another activity (activity2), what's the relationship between these two? Is it possible that Android will kill activity1 since activity2 is te current activity? What if activity2 is not full screen, does that make a difference? -- Andrew

• How to capture emulator screenshots in Eclipse? [1] [2]

• How to export logging data from LogCat to a text file? [3] [4]

• How to create an SQLite database from a CVS file on the Windows Platform?

• How to load the externally created SQLite database into an Android project?
  • Read the "Pre-Creating the Database" section in the textbook (pp. 285-289).
    • the assets folder and the /data/data/<package name>/databases folder

• How do I open the database under data/data using the SqlLite browser?

• Will Android do anything to prevent more than one copy of a content provider being created at the same time? If not - how to prevent data corruption or inconsistency?

Assignment 1 Q&A

• Is the relationship between schedule and student/teacher 1:1? (ie: to delete a schedule you can just delete the account that schedule is attached to) -- Dennis

The assignment specifies we include "validfrom" and "validto" dates. This implies that we could have several schedules for each student/teacher. eg. one for summer, another for fall, etc. However, this being our first assignment I think it would be reasonable to have exactly one timetable per student/teacher. We would then use the "validfrom" and "validto" dates to tell us when the schedule has become outdated.... John