MemoryQuiz

ADVICE: this is create by beginner student for project 3 Udacity Android Basic Nano Degree
Well accepted corrections and suggestions
This APP is a simple memory test: observe an image, then answer to questions.
The java code is divided into 3 different files to implement a Model View Controller:
1.) the usual MainActivity (opens the first screen with the image to observe and a button to start quiz. When start button is clicked, an intent is send to QuestionActivity)
2.) the QuestionActivity (displays the second screen, updating text of the question and a radio button group with 3 choices. When Next is clicked the method updateData fills the view with the next data question.If last question is reached(4) it displays the score
3.) the QuizModel contains the data model: the texts to display, the score, the position of the current question. Here I defined an array of 4 element corresponding to each question. Every element is a combination of question text, choice1 answer, choice2 answer, choice3 answer, number of the right choice answer.