java-返回字符在字符串中出现的次数

    public class StringFind
{
    /** findLetter looks for a letter in a String
    * @param String letter to look for
    * @param String text to look in
    * @return boolean true if letter is in text
    * After running the code, change this method to return
    * an int count of how many times letter is in the text.
    */
    public int findLetter(String letter, String text)
   {
    int count = 0;
    for(int i=0; i < text.length(); i++)
       {
    if (text.substring(i, i+1).equalsIgnoreCase(letter))
               {
              
    count = count++;
               }
       }
       
       
    return(count);
      
   }

    public static void main(String args[])
    {
      
    StringFind test = new StringFind();
    String message = "Apples and Oranges";
    String letter = "p";
    System.out.println("Does " + message +  " contain a " + letter + "?");
        
    }
}

这段代码有一个错误，我不知道如何修复它。这段代码应该返回一个字母在用户输入的消息中出现的次数。我一直在努力想，没有ero我需要改变什么