I can not do the inclusion of the bank

I'm studying android and I'm doing the CRUD from the bank ... only I did the code and put it to run it does not work. It has the layout with a field to write what you want to save and on the side a button, just below has the listview for me to show the saved items from the bank ... When I click the button it does not happen anything, nor the Toast that I put to enter if you need to type something or if it has been saved successfully. I reviewed the code and found nothing, could anyone help me?

MainActivity.java

package com.nathan.listanewn;

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

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

public class MainActivity extends AppCompatActivity {

    private Button adicionar;
    private EditText caixa;
    private ListView lista;
    private SQLiteDatabase banco;


    private ArrayAdapter<String> itensAdptador;
    private ArrayList<String> itens;
    private ArrayList<Integer> ids;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        try{
            adicionar = (Button) findViewById(R.id.btnAdds);
            caixa = (EditText) findViewById(R.id.edtPeca);
            lista = (ListView) findViewById(R.id.listAdd);

            //Criando banco
            banco = openOrCreateDatabase("apptarefas", MODE_PRIVATE,null);

            //tabela tarefas
            banco.execSQL("CREATE TABLE IF NOT EXISTS tarefas(id INTEGER PRIMARY KEY AUTOINCREMENT, tarefa VARCHAR)");


            //evento de click
            adicionar.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    String textodigitado = caixa.getText().toString();
                    salvarTarefa(textodigitado);
                }
            });


            //habilitando o toque longo para exclusao
            lista.setLongClickable(true);
            lista.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
                @Override
                public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                    removeTarefa( ids.get(position));
                    return false;
                }
            });


            //recuperar tarefas
            recuperarTarefa();

        }catch (Exception e){
            e.printStackTrace();
        }
    }


    private void salvarTarefa(String texto){
        try{
            if(texto.equals(" ")){
                Toast.makeText(getApplicationContext(), "O campo não pode estar vazio", Toast.LENGTH_SHORT).show();
            }else{
                banco.execSQL("INSERT INTO tarefas (terafa) VALUES('"+ texto +"')");
                Toast.makeText(getApplicationContext(), "Tarefa foi salva com sucesso", Toast.LENGTH_SHORT).show();
                recuperarTarefa();
                caixa.setText("");
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    private void recuperarTarefa(){
        try{
            //recuperar as tarefas
            Cursor cursor = banco.rawQuery("SELECT * FROM tarefas ORDER BY id DESC", null);

            //recuperar os ids da coluna
            int indiceColunmId = cursor.getColumnIndex("id");
            int indiceColunmTarefa = cursor.getColumnIndex("tarefa");


            //criado list
            itens = new ArrayList<String>();
            ids = new ArrayList<Integer>();

            //criado adptet
            itensAdptador = new ArrayAdapter<String>(
                    getApplicationContext(),
                    android.R.layout.simple_list_item_2,
                    android.R.id.text2,
                    itens) {
                @Override
                public View getView(int position, View convertView, ViewGroup parent) {

                    View view = super.getView(position, convertView, parent);
                    TextView text = (TextView) view.findViewById(android.R.id.text2);
                    text.setTextColor(Color.BLACK);
                    return view;

                }
            };

            //inserindo no adpter
            lista.setAdapter(itensAdptador);

            //listar as tarefas
            cursor.moveToFirst();
            while (cursor != null){
                Log.i("Resultado - ", "tarefa: " + cursor.getString(indiceColunmTarefa));
                itens.add(cursor.getString(indiceColunmTarefa));
                ids.add(Integer.parseInt(cursor.getString(indiceColunmId)));
                cursor.moveToNext();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void removeTarefa(Integer id){
        try{
            banco.execSQL("DELETE FROM tarefas WHERE id="+id);
            recuperarTarefa();
            Toast.makeText(MainActivity.this, "Tarefa removida com sucesso!", Toast.LENGTH_SHORT).show();

        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.nathan.listanewn.MainActivity">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:id="@+id/linearLayout"
        android:layout_marginTop="5dp">

        <EditText
            android:id="@+id/edtPeca"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="textPersonName"
            android:text="" />


        <Button
            android:id="@+id/btnAdds"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Adicionar"
            android:layout_weight="1"
            android:background="@drawable/redondo_salvar"
            android:textColor="#fff"/>
    </LinearLayout>

    <ListView
        android:id="@+id/listAdd"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="80dp"
        android:layout_centerHorizontal="true" />
</RelativeLayout>