Android arrayadapter 不能正常工作

Question

I don't know what i'm doing wrong. I'm a newbie. I need to create a custom list that interact with two EditText(number) and a button. When the user click the button, it generates a list from the first number to the last number and check if the clicked number on list was prime or not... But i get an error in this part: ListView listMod;

            listMod = (ListView) findViewById(R.id.listMod);

            List<Integer> lista = new ArrayList<>();
            for (int i = first; i <= last; i++) {
                listMod.add(i);
            }

            ArrayAdapter<Integer> arrayAdapter = new ArrayAdapter<Integer>(
                    this,
                    android.R.layout.simple_list_item_2,
                    lista);

            listMod.setAdapter(arrayAdapter);

so i don't see what the problem is. I used this code also in another activity. I'll post also the Whole activity: package com.example.andre.thelist;

            import android.app.AlertDialog;
            import android.content.DialogInterface;
            import android.os.Bundle;
            import android.support.design.widget.FloatingActionButton;
            import android.support.design.widget.Snackbar;
            import android.support.v7.app.AppCompatActivity;
            import android.support.v7.widget.Toolbar;
            import android.view.View;
            import android.widget.AdapterView;
            import android.widget.ArrayAdapter;
            import android.widget.Button;
            import android.widget.EditText;
            import android.widget.ListView;
            import android.widget.Toast;

            import java.util.ArrayList;
            import java.util.List;

            public class TheList extends AppCompatActivity {


                @Override
                protected void onCreate(Bundle savedInstanceState) {
                    super.onCreate(savedInstanceState);
                    setContentView(R.layout.activity_the_list);
                    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
                    setSupportActionBar(toolbar);


                    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
                    fab.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            Snackbar.make(view, "Maybe I can use this", Snackbar.LENGTH_LONG)
                            .setAction("Action", null).show();
                        }
                    });



                    Button btn = (Button)findViewById(R.id.gen);

                    btn.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            EditText firstn = (EditText) findViewById(R.id.firstn);
                            EditText lastn = (EditText) findViewById(R.id.lastn);
                            String firstnString = firstn.getText().toString();
                            String lastnString = lastn.getText().toString();

                            if(firstnString.isEmpty() == true || lastnString.isEmpty() == true ) {
                                Integer first = 1;
                                Integer last = 100;
                                Toast.makeText(getApplicationContext(),"Verranno usate le cifre di esempio 1 e 100", Toast.LENGTH_SHORT).show();
                            }
                            final Integer first = Integer.parseInt(firstnString);
                            final Integer last = Integer.parseInt(lastnString);

                            ListView listMod;

                            listMod = (ListView) findViewById(R.id.listMod);

                            List<Integer> lista = new ArrayList<>();
                            for (int i = first; i <= last; i++) {
                                lista.add(i);
                            }

                            ArrayAdapter<Integer> arrayAdapter = new ArrayAdapter<Integer>(
                                this,
                                android.R.layout.simple_list_item_2,
                                lista);

                            listMod.setAdapter(arrayAdapter);

                            listMod.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                                @Override
                                public void onItemClick(AdapterView<?> adattatore, final View componente, int pos, long id) {
                                    final Integer numero = (Integer) adattatore.getItemAtPosition(pos);

                                    //creo il ciclo di controllo valori
                                    if (numero > 0) {
                                        boolean isPrime = true;
                                        for (int i = 2; i <= numero / 2; i++) {
                                            if (numero % i == 0) {
                                                isPrime = false;
                                                break;
                                            }
                                        }
                                        if (isPrime) {
                                            AlertDialog alertDialog = new AlertDialog.Builder(TheList.this).create();
                                            alertDialog.setTitle("Yeah numero primo");
                                            alertDialog.setMessage("Il numero " + numero + " è un numero primo!");
                                            alertDialog.show();
                                        } else {
                                            Toast.makeText(getApplicationContext(), "Il numero " + numero + " non è un numero primo", Toast.LENGTH_SHORT).show();
                                        }
                                    }
                                }
                            });
            }

            });

            }

Thank you for any help

OK, I've modified the line (What a gaffe), but now the console show me other error like:

 Error:(70, 54) error: no suitable constructor found for ArrayAdapter(<anonymous OnClickListener>,int,List<Integer>)
constructor ArrayAdapter.ArrayAdapter(Context,int,int,List<Integer>) is not applicable
(actual and formal argument lists differ in length)
constructor ArrayAdapter.ArrayAdapter(Context,int,List<Integer>) is not applicable
(actual argument <anonymous OnClickListener> cannot be converted to Context by method invocation conversion)
constructor ArrayAdapter.ArrayAdapter(Context,int,int,Integer[]) is not applicable
 (actual and formal argument lists differ in length)
constructor ArrayAdapter.ArrayAdapter(Context,int,Integer[]) is not applicable
(actual argument <anonymous OnClickListener> cannot be converted to Context by method invocation conversion)
 constructor ArrayAdapter.ArrayAdapter(Context,int,int) is not applicable
(actual argument <anonymous OnClickListener> cannot be converted to Context by method invocation conversion)
constructor ArrayAdapter.ArrayAdapter(Context,int) is not applicable
(actual and formal argument lists differ in length)

And

Error:(75, 22) error: cannot find symbol method setAdapter(ArrayAdapter<Integer>)

Also

 Error:(77, 22) error: cannot find symbol method setOnItemClickListener(<anonymous OnItemClickListener>)

Answer 1

Here:

for (int i = first; i <= last; i++) { 
   listMod.add(i);
}

listMod.add(i); line causing issue because listMod is object of ListView and you are trying to call add method on it..

Use lista which is ArrayList for adding items in ArrayList which passing as data-source to Adapter:

for (int i = first; i <= last; i++) { 
   lista.add(i);
}

As in update log:

Error:(77, 22) error: cannot find symbol method setOnItemClickListener()

problem is due to passing this as first parameter in ArrayAdapter.create adapter object as:

ArrayAdapter<Integer> arrayAdapter = new ArrayAdapter<Integer>(
                                TheList.this,
                                android.R.layout.simple_list_item_2,
                                lista);