null pointer

[drjay1627]

I made a maze game. When you click the button, a navigator is created. But before you create a navigator, if you try moving the navigator, there is a null pointer exception.

since the navigator can be moved by pressing keys on the keyboard, I want an error message to appear if and when user tries to move the navigator without creating a navigator.

i want to do

if nav==null //not created
error message
else
do...

how do i do this?

[peter_budo]

As per my other post i regards of key listener, please provide your code

[drjay1627]

figured it out!

try{
//code
}catch(exceptiontype name){ //this case Exception NullPointerException
}