calling method from another activity android -

i have methods in class, mainactivity, want move class clean bit.

when call method mainactivity works perfectly. when call other class, mainactivity2, java.lang.nullpointerexception

here how calling mainactivity: mainactivity2 ma = new mainactivity2(); ma.onlongclick();

my mainactivity2 extends mainactivity

sorry stupid questions, confused why having problem thought knew how call methods other classes...

this works me:

• mainactivity2 doesn't extend mainactivity
• i use following code: new mainactivity2().onlongclick();

try , tell if works ;)