The app crashed: find out why

Why: “the app closes when I tap Buy” is a bug report developers can’t do much with. The stack trace from the device tells them the file and the line. Here you get it in two clicks.

What happens

Logcat is Android’s own log: apps and the system write into it what they do, and a crash leaves its full error there.

1. The app crashes: Android shows “keeps stopping” on the screen.
2. Holtdroid notices it and shows a notification with the first lines of the error. Press Logcat in it.
3. The Logcat tab opens. Red lines are errors: the exception name, its message and the lines starting with at show where in the code it happened.
4. Narrow it down: This app / Everything switches between your app’s lines and the whole device, the level filter keeps only errors, and the text field finds a tag or a word.
5. Download saves what is shown, ready to attach to the ticket.
6. The app stays closed after a crash. Restart app on the App card brings it back.

Good to know

• The log is collected from the moment the device is ready, and survives app restarts and installing another build. You can find a crash that happened ten minutes ago.
• This app follows your app by its user id, so it covers all of its processes and keeps working after restarts.
• For a bug report with everything at once (screenshot, log, device details), use the Bundle button on the Device card.

If it doesn’t work

• No notification appeared: the app may have closed without a crash, for example it called finish() or was killed for memory. Look at Logcat with Everything and the Error level.
• The Logcat tab is missing or says it’s waiting: the tab works over the device’s ADB, which isn’t available to you in someone else’s session.
• The error is in the web part of the app (a white screen, a broken button): look in the DevTools console instead; JavaScript errors don’t crash Android apps.

More details: Logcat, ADB tools.