How to switch between Android Virtual Device ?

You have multiple AVD in your list. The question is you want to switch to another AVD which has different dimension and settings.

Select your project in Package Explorer in left Panel. I have selected my project Android 101. On top menu you see the green arrow RUN button which you use to run the application. Click on the drop down arrow right next to RUN button, you will see following menu as shown in the screenshot below. Select Run Configuration.

After you select the Run Configuration in previous pop up.You will see the new pop up as seen in the screenshot below.  Select Target Tab. You will see your list of AVDs.

You select AVD of your choice and click on Apply. After that you can Click on Run. This will run your project in AVD you have selected. As per the window in the screenshot. Android101 project will run on ReetuSim2 named AVD.