Android studio中Cannot resolve method 'getSex' in 'User'这几个方法不行

问题遇到的现象和发生背景

报错

问题相关代码，请勿粘贴截图

  public boolean register(User user){
    SQLiteDatabase sdb=dbHelper.getReadableDatabase();
    String sql="insert into user(username,password,age,sex) values(?,?,?,?)";
    这一行有问题：Objec obj[]={user.Username(), user.getUsername(), user.getUserpassword(), user.getSex()};
    sdb.execSQL(sql,obj);
    return true;
}

User：
public User(String username, String password, int age, String sex) {
super();
this.username = username;
this.password = password;
this.age = age;
this.sex = sex;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
@Override
public String toString() {
return "User [id=" + id + ", username=" + username + ", password="
+ password + ", age=" + age + ", sex=" + sex + "]";
}

}

运行结果及报错内容

Cannot resolve method 'Username' in 'User'
Cannot resolve method 'getUsername' in 'User'
Cannot resolve method 'getUserpassword' in 'User'
Cannot resolve method 'getSex' in 'User'

我的解答思路和尝试过的方法

能搜到的方法都试了一遍，依旧不行

我想要达到的结果

解决这四条报错

实体类代码贴全吧

Cannot resolve method 'Username' in 'User'
Cannot resolve method 'getUsername' in 'User'
Cannot resolve method 'getUserpassword' in 'User'
Cannot resolve method 'getSex' in 'User'

报错的原因是因为user对象中没有定义这些函数。题主贴的代码显示已经定义了，那么检查下import xxx.user。 是不是引入了其他重名User类。