Other than just swiping the green arrow, there are other ways of answering the incoming calls in Samsung Galaxy Grand 2. One way is to make the Home key to pick your incoming calls. Other way is to control them via Voice. To activate this go to Settings and tap on Accessibility. On the Accessibility screen tap on the Answering/ending calls.
From the Answering/ending calls screen when you tap on The home key answers calls, Grand 2 will allow you to pick the incoming calls when the home key buttons is used. You can also use the power key to end calls by enabling The power key ends calls
To answer calls with voice commands enable the Voice control. This will take you to the Voice control screen. From here, there are options like answering calls with the voice command Answer to pick the call and Reject to drop the call.
There are other options are to control the Alarm, Camera and Music with the voice commands. Enable them if you want to control them too. For e.g. you can take pictures with the voice command Capture. To control Music use the voice command Play and Stop etc.