Well, as an example: you create one activity, with a list of categories. in it, by clicking on the category, the second activation is opened, in which a request for a task list is made. Further when the task list is received you do the following:
If you need to answer questions in order, then this is the case: in the window, the text of the task, the input field and the button. when you click on the button you check the answer, if you are correct, then you increase the counter. check whether the question was the last, if yes - then you will display a message about the number of correct answers, etc., if the question is not the last, then fill in the fields below the next. question.
This is only one of the possible options. You can use fragments to display each question and when answering a question, change one fragment to another.
You can use the viewpager if you need the ability to flip through questions, with the ability to respond in random order.