如何用手指在画布上作画

I am using android Canvas class from creating drawing application. This is my first attempt to work with Canvas class. So far the code that i used is working fine and the drawing is working fine. But what i realized in this code is that, it allow user to draw with one finger only, i mean to say if the user used more then one finger to draw on canvas it doesn't allow the user to draw with multiple finger. I go through several documentation regarding multiple touch event but failed to implement it in my code. So can anyone help me to figure this out. class from creating d