FlixsterPartTwoDebuggingChallange

Debugging strategies

Basic debugging workflow

  • Understand how to reproduce the issue
    • Retrace steps, focus on the input or sequence of inputs that caused the issue (toasts)
  • Figure out the most likely reasons the problem occurred
    • Think about the tasks that would be happening as the app crashes and which ones you suspect might be causing this kind of crash
  • Review each suspect and narrow down until you have a culprit
    • Use logcat/toasts/debugger to track down the exact cause of the issue
  • Brainstorm potential solutions
    • Think about what you can change to fix this issue
  • Resolve the issue
    • Implement the changes and test the app

3 Main ways to debug

  • Toasts : small in app notifications
  • Logging with logcat : sending data to the log ( viewable from logcat)
  • Debugger witgh Breakpoints : Set a breakpoint so you can pause app execution and look at variable states at specific points

Toasts : best as a preventative

Good

  • Very fast to set up
  • Easy to see while using app normally

Bad

  • Can not stack, some may not show if multiple try to play at the same time
  • They can not be copied from and do not persist

Best times to use

  • Checking if things that fail gracefully (no crash/error ) are working during normal use
  • Examples Listeners, and Asynchronous callbacks

Logging : with Logcat

Good

  • Easy to check multiple things at the same time
  • Can be reviewed after crash
  • Most crashes will show up in logcat with a Line #
  • Can filter based on options

Bad

  • It can be hard to use while using the app, so you may be forced to review after crash or after run.

Best times to use

  • First place to check if you get an unexpected crash
  • If you are unsure if an API call is working you can print the response URL and check in browser.
  • If you are looking for the cause of a crash that is coming form a code you have not written (example glide or room)

Breakpoints : with the Debugger

Good

  • Gives you the absolute most information about the state of variables.
  • Requires no extra lines of code
  • Allows for line by line code execution

Bad

  • Line by line code exploration can take a lot of time
  • Can make Async functions (API calls) break

Best times to use

  • When you know the issue is related to a variable assigned an unexpected value (null, or junk), but you are unsure where
  • When you are unable to find the cause via Logging

Hints

  • Have you checked log cat?
  • Which layout should we be using? Constraint or Relative 🔍
  • How big is the list of movies we're returning?
  • How do we launch an activity?
  • Have you Taken a look at the XML file?
  • Take a look at the Movie model...