Android debug tips and tricks

Below is a set of notes to myself regarding various Android debugging tips and tricks, mostly using adb command-line utility from Android SDK.

Unlocking developer options menu (device)

  • Locate the Build number field in the options, and tap it 7 times.

Detecting devices (host)

  • To be able to properly detect/see connected devices without running adb as root:
    • determine USB vendorId of the target device using lsusb
    • create a udev rules file (e.g. /etc/udev/rules.d/51-android.rules)
    • edit it and add SUBSYSTEM=="usb", ATTR{idVendor}=="<vendorId>", MODE="0666", GROUP="plugdev"
    • restart udev: sudo service udev restart
    • kill adb: sudo killall adb̀
    • unplug and replug device
    • device should now be listed properly when executing adb devices

Handling multiple connected devices (host)

  • To target adb commands at one specific device when several are connected, use: adb -s <target device ID> shell

Get logs (host)

  • To get the timestamped logcat traces from a remote host : adb logcat -v time > logcat.txt
  • To clear the logcat: adb logcat -c

Install application (host)

  • To force the (re)install of an application package: adb install -r app.apk

Launch application (host)

  • To launch a specific app: ./adb shell am start -n <packageName>/<packageName>.<ActivityName>

Simulate user inputs (host)

  • Simulate a wake/power-on : adb shell input keyevent 224
  • Simulate a power toggle : adb shell input keyevent 26
  • Simulate a user touch at coordinates x,y : adb shell input tap x y

Get system info (host)

  • LARGE system info dump : adb shell dumpsys
  • Power management system info dump : adb shell dumpsys power
  • Dumpable subcategories: adb shell dumpsys | grep "DUMP OF SERVICE"

Get touch coordinates (device)

  • Activate the associated function in Developer Options menu in the device’s settings: a bar at the top of the screen will show x and y coordinates of any touched point.

Remote screenshot (host)

  • To grab a screenshot from the host: adb shell screencap -p | perl -pe 's/\x0D\x0A/\x0A/g' > screenshot.png

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