Make necessary chages in YouTubeActivity.java File
// Add your Google API KEY
// Remove dots and add yr Google API key here
static final String GOOGLE_API_KEY="....";
// If you want to view
// for example the following link in yr app
// https://www.youtube.com/watch?v=9YrmON6nlEw&list=PLS1QulWo1RIaUGP446_pWLgTZPiFizEMq
// v is the YOUTUBE_VIDEO_ID
// v=9YrmON6nlEw
// list is the YOUTUBE_PLAYLIST
// list=PLS1QulWo1RIaUGP446_pWLgTZPiFizEMq
static final String YOUTUBE_VIDEO_ID="9YrmON6nlEw";
static final String YOUTUBE_PLAYLIST="PPLS1QulWo1RIaUGP446_pWLgTZPiFizEMq";
// After the changes , the codes will look like this
static final String GOOGLE_API_KEY="GOOGLE-API-KEY";
static final String YOUTUBE_VIDEO_ID="9YrmON6nlEw";
static final String YOUTUBE_PLAYLIST="PPLS1QulWo1RIaUGP446_pWLgTZPiFizEMq";