How to use replaceAll() correct

Question

I have a hangman-app which I fetch a random word from Db i created, then I save it to randomedWord and then i make another String for holding randomedWord but replaced with only "_". This hiddenWord is displayed so the user knows how many chars there is.

When a user hits Enter a onlicklistener fires guess() method:

I have following code which initates a local String which has the value of a TextView(userInput). Then if randomedWord contains the guess I want to put in guess into the same position as it is in the randomedWord, but now to hiddenWord and then update the TextView again.

Guess method:

public void guess() 
{
    String guess = userInput.getText().toString();

    if(randomedWord.contains(guess)) 
    {
        hiddenWord = hiddenWord.replaceAll(guess, guess);
        this.wordHolder.setText(hiddenWord);
    } else 
    {
        showImages();
    }
}

The problem I think is this line:

hiddenWord = hiddenWord.replaceAll(guess, guess);

because hiddenWord just contains "_" and therefore I can't replace with (guess, guess) where the first is WHAT to be replaced and last is WITHWHAT.

How do I replace the same POSITION as it is in randomedWord with guess into hiddenWord?

Answer 1

Got it all solved! The feeling when everything works smoothly.... :)

Heres the code:

// Set listener to enter-button and do guess when textfield is not empty and toast that input need if it is

 enterLetterButton.setOnClickListener(new OnClickListener(){
            public void onClick(View arg0) {

                if (!(userInput.getText().toString().isEmpty()) )
                {
                    guess();
                } else if (userInput.getText().toString().isEmpty())
                {
                    Toast toast = Toast.makeText(getApplicationContext(), "You need to insert a letter", Toast.LENGTH_SHORT);
                    toast.show();
                }
            }
        });

// invWord() method. Converts the randomedWord to a string of "_".

public void invWord() 
    {
        hiddenWord = randomedWord;
        hiddenWord = hiddenWord.replaceAll(".", "_" +" ");
    }

//guess() method. Puts the guess(char) at the index fetched and if the hiddenWord contains no more "_" winner() is called

  public void guess() throws IndexOutOfBoundsException
        {
            char guess = userInput.getText().charAt(0);
            StringBuilder builder = new StringBuilder(hiddenWord);
            String j = ""+guess;
            int index = randomedWord.indexOf(guess);

            if (randomedWord.contains(j))
            {
                while (index >= 0) 
                {
                    builder.setCharAt(index*2, guess);
                    index = randomedWord.indexOf(guess, index + 1);
                    hiddenWord = builder.toString().trim();
                    wordHolder.setText(hiddenWord);
                    if (!(hiddenWord.toString().contains("_".toString())) )
                    {
                        winner();
                    }
                }   
            }
            else 
            {
                showImages();
            }
        }