need to call a function which uses 'this' outside of the main activity in Android

This is the error I get when I try this call from an outside class. Thanks in Advance.

Function Call

GuessingLettersActivity.userGuess();

Error

Cannot make a static reference to the non-static method userGuess() from the type GuessingLettersActivity

Function in Main Activity (GuessingLettersActivity)

public  void userGuess()
{
    AlertDialog.Builder alert = new AlertDialog.Builder(this);

    alert.setTitle("Enter A Guess");
    alert.setMessage("Enter your guess below. Just enter the letter or symbol. It is case sensitive!");

    // Set an EditText view to get user input 
    final EditText input = new EditText(this);
    alert.setView(input);

    alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
      CharSequence val开发者_如何学JAVAue = input.getText();


    }
    });

    alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int whichButton) {
        // Canceled.
      }
    });

    alert.show();
    // see http://androidsnippets.com/prompt-user-input-with-an-alertdialog 

}  

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to activate non static method, you must have an instance, otherwise - what will this refer to?

you can create a dummy instance and invoke userGuess() on it: (new GuessingLettersActivity()).userGuess();

however, if you realy do not need an instance, the this is not really needed, find a way not to use it, and declare userGuess() as static, it will be much more elegant.

if the instance is critical, there is a code smell here, how come you want to invoke userGuess() as static, but you need a specific instance? this can create a bug that will be caught only on later stages, so I suggest investigating it now.

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The solution was to change how I get context in the onCreate function. It is not this which is passed to the alertDialog function and works like a champ

context = this;

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The reason for this is because you are trying to make a static reference to a non-static method as the error suggests. Change your method signature to the following:

public static void userGuess()