怎么把减号也弄进去，刚学别嫌我菜😫

public int pressEquals(){
int result = 0;
String flag = null;
for(int i = 0;i < pressButtonIndex;i++){
if(!pressButton[i].equals("+")){
if(result == 0){
result = Integer.parseInt(pressButton[i]);
}else{
if(flag.equals("+")){
result = result + Integer.parseInt(pressButton[i]);
}
}
}else{
flag = "+";
}
}
return result;
}
}

 public int pressEquals() {
        int result = 0;
        String flag = null;
        for (int i = 0; i < pressButtonIndex; i++) {
            if (!pressButton[i].equals("+")) {
                if (result == 0) {
                    result = Integer.parseInt(pressButton[i]);
                } else {
                    if (flag.equals("+")) {
                        result = result + Integer.parseInt(pressButton[i]);
                    }else if(flag.equals("-")){
                        result = result - Integer.parseInt(pressButton[i]);
                    }
                }
            } else {
                flag = "+";
            }
         
        }
        return result;
    }
}

if(flag.equals("+")){}
else if(flag.equals("-")){}