android
...
adb
is a CLI that
lets you control your Android device from your computer. In this post I want to
share its features that made me enjoy more mobile development.
Initial Setup
First, you’ll need to connect your device to your computer, either
through
USB
or
purely
Wi-Fi
(
if you’re on Android 11+
), but it’s also possible to use
adb
over Wi-Fi on
Android 10 or lower if you follow some
initial
steps
while
connected over USB.
If everything works correctly, by running
adb devices
you should see
something like this:
Bash
$ adb devices List of devices attachedemulator-5554 device0035714150 device
Record screen with
adb shell screenrecord
To record your screen, it’s as simple as running
adb shell screenrecord /sdcard/video.mp4
. After you’re done, press
Ctrl
+
C
.
Run
adb pull /sdcard/video.mp4 ~/Videos/video.mp4
to get the video into your
computer.
It’s also useful to know some of the
command line
options
,
my favorite ones being to limit the video size with
--size
and recording time
with
--time-limit
.
For example, I typically run
adb shell screenrecord --size 320x568 --time-limit=120 /sdcard/video.mp4
.
Capture screen with
adb shell screencap
This is straightforward, it just captures the screen with
adb shell screencap /sdcard/img.png
, then getit locally with
adb pull /sdcard/img.png ~/Images/img.png
.
Debugging with
adb logcat
This has proved useful to me so many times. In the context of React Native
development, this is usually less useful in debug builds. But in release builds
it’s sometimes the only way to debug when something wrong happens.
For example, when an app crashes or some SDK call is not working, you’ll
probably be able to see why with
adb logcat
.
The downside is that the output can be overwhelming, since it’s a huge wall of
text that is growing constantly. So it pays off to know how to filter it, e.g.
if I wanted to see only logs tagged with
Sentry
,
ReactNative
and
ReactNativeJS
at any priority level:
Bash
$ adb logcat Sentry:* ReactNative:* ReactNativeJS:* *:S
The official Google
documentation
explains nicely how this works.
Networking with
adb reverse
Imagine you want to see your
Storybook
files in a
mobile web browser. If you go to
localhost:6006
in your computer’s browser,
it works, but nothing shows up in your mobile device’s browser, since no
process is bound to port
6060
there.
You can solve this problem by running
adb reverse tcp:6006 tcp:6006
. Now your
mobile device will have access to the server running on your computer.
An example from React Native is the Metro bundler, that usually serves the
bundled JS of your app at port
8081
, so we need to run
adb reverse tcp:8081 tcp:8081
to make the server available in your mobile device. This is usually
done under the hood when we run
npx react-native run-android
, but if the
device can’t find the JS bundle or is stuck loading it we usually need to run
it again.
There’s also
adb forward
, in case you need to make a web server running on
your phone also available in your computer.
Start/kill apps
You can start and kill an app with the
adb shell am
, in which
am
stands for
Activity Manager
.
Given the app’s package name, you can start it with:
Bash
$ adb shell am start -a android.intent.action.VIEW -d company://Screen
Install/uninstall apps
You can install an
.apk
file with
adb install app.apk
.
And uninstall it with
adb uninstall com.company.app
.
This is usually how I do it, but there’s also the
pm
command, which stands
for
Package
