Simulate killing of activity in emulator

There's a more solid solution for this in Android 6 and newer. I've used the following method successfully on Android 6, 7, and 8:

1) Open your app, go to the activity that you want to test restoring, and then leave it by pressing the Home button

2) Open the Settings app, go to System -> Developer Options, then tap on "Running Services"

3) Tap on "Show Cached Processes" at the top right, then find your app in the list, tap on it, and then tap the "Stop" button.

4) Use the recent apps list to return to your app. It should relaunch the whole app on the activity that you had previously left it from.

I've found this to be sufficient to fully kill the app, including any app delegate stuff and the C/C++ native code state, and then test relaunching it with a saved activity state... This effectively replicates what happens when the user leaves the app for a while and then the system kills it to save memory, battery, or whatever.

You can pause your application (by pushing the Home button, simulating a call, whatever). Then kill the app's process through adb. Since the docs say that after onPause() returns your app can be killed without any further notice, this is a fair test.

If you don't want to go through the trouble of finding the pid of your app's process, you can use adb shell am kill com.example.package_name to kill your app's process. Make sure that the app is put in the background. The docs say that this command "kills only processes that are safe to kill and that will not impact the user experience." So you might want to launch a couple of other apps before trying this one.