如何将代码从片段更改为活动

Question

我是Android的新手，遇到了一些问题，我正在制作一个StudentArraylist来查看我的firebase数据库中的学生，以便在ListView中显示它们。但我面临一些问题，因为我现在的代码我的意思是片段但不是活动和 这是我的错误 这是ViewStudentActivity

    StudentArrayList adapter = new StudentArrayList(getActivity(),studentList);
            studentlist.setAdapter(adapter);

1. 这是StudentArrayList：

   public StudentArrayList(Activity context, List<Student>studentList){
   super(context, R.layout.student_list, studentList);
   this.context = context;
   this.studentList = studentList;
   }
   
   @NonNull
   @Override
   public View getView(int position, @Nullable View convertView, @NonNull 
   ViewGroup parent) {
   LayoutInflater inflater = context.getLayoutInflater();
   
   View listViewItem = inflater.inflate(R.layout.student_list, null, true);
   s_sid = (TextView)listViewItem.findViewById(R.id.txtSid);
   s_name = (TextView)listViewItem.findViewById(R.id.txtName);
   s_email = (TextView)listViewItem.findViewById(R.id.txtEmail);
   s_fyp = (TextView)listViewItem.findViewById(R.id.s_fyp);
   btnUpdate = (Button) listViewItem.findViewById(R.id.btnUpdate);
   firebaseDatabase = FirebaseDatabase.getInstance();
   pdatabaseReference  = firebaseDatabase.getReference();
   auth = FirebaseAuth.getInstance();
   
   final Student student = studentList.get(position);
   
   s_sid.setText("Student ID : " + student.gets_sid());
   s_name.setText("Student Name : " +student.gets_name());
   s_email.setText("Date : " +student.gets_email());
   s_fyp.setText("Time Start : " +student.gets_fyp());
   
   
   return listViewItem;
   
   }