Sites and apps similar to Tutorial Reference include freeCodeCamp, which is free and open source. Other options are W3Schools, tutorialspoint and SitePoint. In total there are four Code Learning Services like Tutorial Reference for Android.
Free Code Camp's open source community help you build a job-worthy portfolio of real apps used by real people, while helping nonprofits.
United States
W3Schools is a web developers information website, with tutorials and references on web development languages such as HTML, CSS, JavaScript, PHP, SQL, and JQuery, covering most aspects of web programming.
Norway
Free tutorials and reference manuals with examples for Computer Fundamentals, JSF, C Sharp, Flex, GWT, PL/SQL, Eclipse, JUnit, Pascal, Maven, Scala, Spring, Struts 2, HTML5, ANT, iBATIS, Django, JSP, JAVA, JDBC, AJAX, WAP, SQL, MySQL, C/C++, PERL, PHP, Ruby, Ruby on Rails...
India
Learn Web Design and Development with SitePoint tutorials, courses, and books - HTML5, CSS3, JavaScript, PHP, mobile app development, Responsive Web Design.
