While testing different applications you will get to the need of testing the following scenario:

The user is opening the application, clicks the Overview button which sends the application
to background and reopens the application by choosing it from the recent used application.

To be able to do that you need to know how to implement two important actions:
1. Click the Overview button which send the application to background; for doing this you can use the following
code snippet written in Java:

    public void clickOverviewButton(){
		((AndroidDriver<WebElement>)driver).pressKeyCode(AndroidKeyCode.KEYCODE_APP_SWITCH);
	}

Hope this helps with your daily testing tasks. Details on how to use the Overview, Home and Back buttons in Appium for Android