Getting error with usingOAuth2

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http://stackoverflow.com – I am using Google drive API with my eclipse android project which is to upload images in to google drive programmatically. I followed the link https://developers.google.com/drive/quickstart-android to develop a sample application, but getting error with usingOAuth2 in oncreate method. Could anyone please help me to sort out this error. Thanks in advance (HowTos)