car loan calculator detail

This carloancalculator app give monthly payment or amortization.
There are three EditTexts and four Spinners. Three EditTexts are car total price , down payment, interest rate. Four Spinners are loan start year , loan start month, how many years and how many months loan.
The user should give those information the car total price (car price, tax, other costs), down payment, interest rate.
The user can select loan start year (current year back to 6 years), loan start month, how many years and how many months loan. When the user doesn't give car price ,down payment or interest rate shows error message. Spinners have default value for loan start year current year, for loan start month 'Jan', for how many years '0' and how many months '6'. The user want to see only monthly payment click "Monthly Payment" button and the monthly payment shows below the button at TextView. The user want to see detail or amortization. The user clicks "Detail Payment" button and it goes to another activity. The activity shows table of four columns and (how many years + how many month) rows. The columns name are Month-Year,Principal,Rate and Loan.