I have a Strange problem with the new ADT version. I have downloaded the new Eclipse from eclipse.org then I install ADT on it. Everything works fine; I can create a project
@shayan pourvatan already answered this question properly for me, i am just adding those two images describing how to install the API 20 L Version to use it then as the Preview renderer.
You could update your 4.4W SDK to 4.4W2 SDK. That fixed mine.
this problem happened on API 20 ( Android 4.4 W ) I recently have a problem with that but Problem will be solved by changing Android version to use for rendering level form API 20 ( Android 4.4 W ) to API 19 (Android 4.4.2) ( android icon in top right corner of graphical layout ) or update your SDK to Android L ( API 20 L preview )
Screen Shot :
I was having this same problem with 20 (4.4W), but it disappeared when I installed and chose 20 (4.4 L (preview)). This is probably because 4.4W is the Android Wear SDK, and so may not support all the features of standard phone/tablet Android
Android Wear is a wrist watch and you cannot type anything in it so you cannot use EditText on 4.4W. Change the API to 19 or less or change it to 4.4L which can be downloaded from SDK Manager. This is not a bug.