Question

I do an import of the full package name / java file, and if I do a <classname>.<method>, SOMETIMES I can get it to access – other times I get a lot of can't use a static in a non static bunch of talk.

I’ll admit I’m new to Java, so what do I need to do? Call a class instance first, then call my methods? I’m rather confused by this, as I want to put all of my ‘functions’ into a FunctionsList.java file, and all of my main Activity (UI) into a MyActivity.java file.

For example:

<MyActivity.java>

import com.example.FunctionsList;

private class MyActivity extends Activity {
  FunctionsList.function();
}

9/10 times I get that static/non-static error.

If I put all of my functions into MyActivity.java, I have zero problems! Anyone help me on what I presume is a basic Java newbie issue?

Answer 1

Here’s an example that will hopefully help you out a little.

public class MyFunctionClass {

   public String myFunction() {
      return "This is an instance function.";
   }

   public static String myStaticFunction() {
      return "This is a static function.";
   }

}

Then in your activity you have something like this.

public class MyActivity extends Activity {

   @Override
   public void onCreate() {

      // If you want to call your static function, you do not
      // require an instance of a MyFunctionClass object.
      String myStaticString = MyFunctionClass.myStaticFunction();

      // If you want to call your instance function, then you need
      // to create a MyFunctionClass first.
      MyFunctionClass variableName = new MyFunctionClass();
      String myInstanceString = variableName.myFunction();
   }
}

As Jon mentioned, you’ll probably save yourself some frustration if you read up on object-oriented programming before diving in. There are some basic things that a new programmer will need to understand before diving in. Good luck!