In amongst the new features ushered in with Android KitKat was a screencasting capability—a native tool for capturing on-screen activity in a video file. Whether you want to show off your app, share your Angry Birds prowess or start a series of Android troubleshooting videos, it's not difficult to get the functionality up and running, as we'll explain in the steps below.
Before we go any further, you will need Android 4.4 KitKat running on your phone or tablet to follow this guide, as the native feature isn't available in earlier versions. You'll also need to activate developer mode on your device but there's no need for root access if you don't mind using a computer. There are a handful of different ways you can tackle the job—including using third-party apps—but here we'll focus on the native capabilities built into Android 4.4 KitKat.
First you're going to need to get your phone or tablet into developer mode. Head to the About section of the Settings app then tap the Build number seven times. Congratulations! You're now a developer, with a brand new Developer options menu. Head into this and tick the USB debugging option and confirming your choice.
Next, you need the Android SDK software package, which you can download straight from Google for your desktop operating system of choice. Once you've installed the suite of tools, your computer is able to give your mobile device the screen capture commands. If you're on a Windows machine then you also need to download the relevant USB drivers for your phone or tablet.
All of this makes sure your desktop computer can talk to your phone or tablet in the right language. The installations aren't difficult, but you can find plenty of online tutorials if you run into problems. There are a few extra pointers in our guide to installing the Android L preview. You can put the Android SDK files anywhere on your system as long as you remember where they are.
With all that software set up we're just about ready to start capturing video. Connect up your device to your computer and make sure the USB storage option is set to Camera (PTP) rather than Media device (MTP) — you should be able to access the relevant option from the drop-down notification drawer.
Open up a command prompt from the sdk/platform-tools folder where you've extracted the Android SDK package. In Windows File Explorer you can do this through the File menu or via the menu that appears with a Shift+right-click combination; on a Mac, use the Terminal app. Use the command
adb devices to make sure this is going to work. If nothing is listed, you've gone wrong somewhere.
adb shell screenrecord /sdcard/video.mp4 is the one you need to start the screencasting, replacing "video" with the filename of your choice (you can choose a different path as well if you like). On-screen activity will be recorded as a video file in the location you've selected until you press Ctrl+C (or Cmd+C) on your computer. You can then open, export and edit the video as you like, either on your device on on your connected machine.
If you want viewers to be able to keep up with what you're doing on your Android device then you might want to switch on the Show touches option from the Developer options menu we mentioned earlier. There are also a number of additional parameters you can add to the screen record command (such as setting a time limit). Type
adb shell screenrecord -help to see what your options are.
That's all there is to it—fairly painless and useful for a whole range of purposes. If you've already rooted your device then you can trigger the screen record command using a third-party app without the need for a computer, and there are several available to do the job on Google Play (SCR Screen Recorder Pro and KitKat Screen Capture for example).