如何从另一个类Android的方法调用字符串

Question

Hello I am new to android,java and I want to use the string from a method from another class. Specifically I want to use the String s from to class Test to class MainActivity. I tried to call it like

Test.AnswerQ1

but it says that cannot resolve symbol "AnswerQ1"
This is my Test class

public class Test extends Activity {




 private RadioGroup radioGroupQuestion1;
 private RadioButton radioButtonQuestion1;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

   radioGroupQuestion1 = (RadioGroup) findViewById(R.id.radioGroupQ1);


   Button NextButton = (Button) findViewById(R.id.Q1NextButton);
    NextButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {

           int selectedId =  radioGroupQuestion1.getCheckedRadioButtonId();
            radioButtonQuestion1 = (RadioButton) findViewById(selectedId);
            String AnswerQ1 = radioButtonQuestion1.getText().toString();
            String Question1 = getString(R.string.Q1);
            System.out.println(Question1);

           System.out.println(AnswerQ1);

           Intent myIntent = new Intent(view.getContext(),  Question2.class);
            startActivityForResult(myIntent, 0);
        }
    });
}

And this is my MainActivity class

public class MainActivity extends Activity{

String myData = Test.s;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

   System.out.println(myData);   

   } 
}

Answer 1

Try with initializing string on the top of an onCreate method. 

public class Test extends Activity {

public static String s = "hello world";

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

   }
}

Answer 2

Don't declare a static member inside instance method.

You must declare a static member as class member not local member.

Example:

public class Test extends Activity { 
    public static String s = "hello world"; 

    public void onCreate(Bundle savedInstanceState){ 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
    } 
}

Answer 3

You can make s public static But there are many other solution. Dependent on your need, You can use Shared Preference , Broadcast Listener , Interface etc.