可以实现数值分析中的欧拉法、后退欧拉法和改进欧拉法的计算，程序中涉及到拉界面，以及许多控件的使用。,Numerical analysis can be achieved in the Euler, backward Euler and improved Euler s method of calculation, the procedure involved in drawing interface, as well as the use of many controls.

java的自定义控件，自定义控件的使用，J2me控件的编写-java custom control, custom control to use, J2me control preparation