Create Android Studio plugin to toggle “Show layout bounds” (Part 2)

This post was created alongside the video that I posted on my YouTube channel 🎥

This article is part 2 of the two-article series on how to create a very simple Android Studio plugin.

In the previous article, I’ve shown you how to create a plugin that gets the list of all connected devices and display a simple notification. If you haven’t seen it you can check it out here:

Create Android Studio plugin to toggle “Show layout bounds” (Part 1)

In this article, we will finish our plugin. The end result of this tutorial will be a plugin that allows toggling layout bounds option on all connected devices:

1. How to enable some developer option from ADB?

As far as I know, most developer options cannot be enabled using ADB but fortunately, “Show layout bounds” is one of the exceptions.

And found out about it thanks to this stack overflow answer which shows that to show layout bounds we can use this ADB command:

adb shell setprop debug.layout true
adb shell service call activity 1599295570

Using this command we set debug.layout property on a connected device to true and then poke the SystemProperties to see the changes. This enigmatic number at the end of the second command (1599295570) is SYSPROPS_TRANSACTION and this flag is used by the settings app to refresh the setting.

Before we will use this command in the plugin we can test in the terminal that it actually works:

2. Run ADB shell command in the plugin

Since in the previous video we learned how to get a list of connected devices the remaining part is pretty easy. For each connected device, we can call executeShellCommand method and pass the command I showed you earlier as a parameter.
The second parameter to specify is a command output receiver. And since we just want to fire our command and don’t care about the response (for now) we will just use NullOutputReceiver:

3. Build the plugin and check out if it works

This step was covered in the previous part so if you haven’t already check it out.

In short: we click the build button and after the project builds a new .jar file is generated. Then we can install our updated plugin from this file on our discs in the Android Studio “Preferences” screen, in the “Plugins” section.

After the plugin is installed and Android Studio restarts our plugin allow is to enable the “Show Layout Bounds” option from the tools menu:

Hide show layout bounds

Obviously, our plugin needs some improvement. Now we can only enable show layout bounds using the plugin but to disable this option we still have to manually go to settings.

The easiest way to improve it would be to just add another option in which we set debug.layout property to false instead of true. But let's spice things up a little and modify our action so it’ll be able to detect if the “Show layout bounds” option is enabled and toggle it.

4. Detect if the “Show layout bounds” option is enabled

Detecting if the “Show layout bounds” option is enabled is fairly easy. We can use a very similar adb shell command as before. But this time instead of calling setprop on debug.layout property we use getprop command:

adb shell getprop debug.layout

In response, if some device is connected, we will receive true or false depending on if this option is currently enabled

Use getprop command in the plugin

First, in the code of our plugin, we have to read the value of debug.layout flag:

This time we need to read and process the first line of the response so we need to also implement a new class SingleLineReceiver which inherits from MultiLineReceiver class and processes just a first line of the response and then mark that receiver was cancelled:

After that we can process the response and set layout bounds to the exact opposite of what was already set:

And that’s it! Our plugin is done! 🎉

Github

When in doubt you can also see my Github repository which contains everything we covered in this article:

PaulinaSadowska/layoutBoundsPlugin

Check out my other articles:

• How Dagger, Hilt and Koin differ under the hood? (+ video 🎥)
• Measure and optimize bitmap size using Glide or Picasso (+ video 🎥)
• Can you trust time measurements in Profiler? (+ video 🎥)