复选框在android中无法正常工作

I have made a simple checkbo[x demo program in android,in that i've put a chekbox and a button.I want is that when chekbox is pressed and button is pressed thet toast showing "i accept" else when button pressed toast generated as "i dont accept"...i have made it but problem is when i unchecked the chekbox..it shows toast directly(without clicking button);I have made a simple checkbo[x demo program in