Issue completing getTileCount challenge. How to have method accept char

I'm trying to complete the getTileCount challenge. I have written the code below. When I define getTileCount (public int getTileCount()), I get an error when I check my work saying: "Did you forget to create the method getTileCount that accepts a char?"

If I define getTileCount like this (public char getTileCount()), I get a syntax error about lossy conversion from int to char

If I define getTileCount like this (public int getTileCount(char tile)), I get a syntax error in line 23 saying char tile is already defined.

Can someone clarify what is making this code not work in the way the challenge is looking for?

public class ScrabblePlayer {
  private String mHand;

  public ScrabblePlayer() {
    mHand = "";
  }

  public String getHand() {
   return mHand;
  }

  public void addTile(char tile) {
    // Adds the tile to the hand of the player
    mHand += tile;
  }

  public boolean hasTile(char tile) {
   return mHand.indexOf(tile) > -1;
  }

  public int getTileCount(){
    int count = 0;
    for (char tile: mHand.toCharArray()){
      if(mHand.indexOf(tile)>=0){
        count++;
      }
    }
     return count; 
  }
}