Fiz o código do FAB e depois refatorei. Acredito que deva estar faltando alguma coisa.
package br.com.viktorrocha.agendanova.ui.activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import br.com.viktorrocha.agendanova.R;
import br.com.viktorrocha.agendanova.dao.AlunoDAO;
public class ListaAlunosActivity extends AppCompatActivity {
private final AlunoDAO dao = new AlunoDAO();
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_lista_alunos);
setTitle("Lista de alunos");
configuraFabNovoAluno();
}
private void configuraFabNovoAluno() {
FloatingActionButton botaoNovoAluno = findViewById(R.id.activity_lista_alunos_fab_novo_aluno);
botaoNovoAluno.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
abreFormularioAlunoActivity();
}
});
}
private void abreFormularioAlunoActivity() {
startActivity(new Intent(this,
FormularioAlunoActivity.class));
}
@Override
protected void onResume() {
super.onResume();
configuraLista();
}
private void configuraLista() {
ListView listaDeAlunos = findViewById(R.id.activity_lista_alunos_listview);
listaDeAlunos.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, dao.todos()));
}
}
