I recently downloaded android studio 2.3.3. I am kind of a beginner in java programming, and I am proceeding with app building after some practice in programming using IntelliJ IDEA. I was learning using a video course, and in the video, an android model appears in the preview. When I downloaded it, there is no android showing, just an arrow. I tried making changes in the settings but none worked. I don't know why this is happening, but I am guessing it is happening because there is a problem with the zip file. I would appreciate if I got some help
You can download gradle yourself and syn with android studio
For detailed step by step solution ,follow this YouTube video
You may need to create a new AVD. Follow this guide https://developer.android.com/studio/run/managing-avds.html#createavd Then in the preview panel , right next to the android icon, null is written there. Click on it to choose the preview device.
来源：https://stackoverflow.com/questions/45416840/there-is-no-android-device-showing-in-my-android-studio