public class AlunosAdapter extends BaseAdapter {
    private final List<Aluno> alunos;
    private final Context context;
    public AlunosAdapter(Context context, List<Aluno> alunos) {
        this.context = context;
        this.alunos = alunos;
    }
    @Override
    public int getCount() {
        return alunos.size();
    }
    @Override
    public Object getItem(int position) {
        return alunos.get(position);
    }
    @Override
    public long getItemId(int position) {
        return alunos.get(position).getId();
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        Aluno aluno = alunos.get(position);
        LayoutInflater inflater = LayoutInflater.from(context);
        View view = convertView;
        if (view == null){
            view = inflater.inflate(R.layout.list_item, parent, false);
        }
        TextView campoNome = (TextView) view.findViewById(R.id.item_nome);
        campoNome.setText(aluno.getNome());
        TextView campoTelefone = (TextView) view.findViewById(R.id.item_telefone);
        campoTelefone.setText(aluno.getTelefone());
        ImageView campoFoto = (ImageView) view.findViewById(R.id.item_foto);
        String caminhoFoto = aluno.getCaminhoFoto();
        if (caminhoFoto != null){
            Bitmap bitmap = BitmapFactory.decodeFile(caminhoFoto);
            Bitmap bitmapReduzido = Bitmap.createScaledBitmap(bitmap, 100, 100, true);
            campoFoto.setImageBitmap(bitmapReduzido);
            campoFoto.setScaleType(ImageView.ScaleType.FIT_XY);
        }
        return view;
    }
}
public class MainActivity extends AppCompatActivity {
    private ListView listaAlunos;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listaAlunos = (ListView) findViewById(R.id.lista_alunos);
        listaAlunos.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> lista, View item, int position, long id) {
                Aluno aluno = (Aluno) listaAlunos.getItemAtPosition(position);
                Intent intentVaiProFormulario = new Intent(MainActivity.this, FormularioActivity.class);
                intentVaiProFormulario.putExtra("aluno", aluno);
                startActivity(intentVaiProFormulario);
            }
        });
        Button novoAluno = (Button) findViewById(R.id.novoAluno);
        novoAluno.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentVaiProFormulario = new Intent(MainActivity.this, FormularioActivity.class);
                startActivity(intentVaiProFormulario);
            }
        });
        registerForContextMenu(listaAlunos);
    }
    private void carregaLista() {
        AlunoDAO dao = new AlunoDAO(this);
        List<Aluno> alunos = dao.buscaAlunos();
        dao.close();
        AlunosAdapter adapter = new AlunosAdapter(this, alunos);
        listaAlunos.setAdapter(adapter);
    }
    @Override
    protected void onResume() {
        super.onResume();
        carregaLista();
    }
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, final ContextMenu.ContextMenuInfo menuInfo) {
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) menuInfo;
        final Aluno aluno = (Aluno) listaAlunos.getItemAtPosition(info.position);
        MenuItem itemLigar = menu.add("Ligar");
        itemLigar.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener(){
            @Override
            public boolean onMenuItemClick(MenuItem iem){
                if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.CALL_PHONE)
                        != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(MainActivity.this,
                            new String[]{Manifest.permission.CALL_PHONE}, 123);
                }
                else {
                    Intent intentLigar = new Intent(Intent.ACTION_CALL);
                    intentLigar.setData(Uri.parse("tel:" + aluno.getTelefone()));
                    startActivity(intentLigar);
                }
                    return false;
                }
        });
        MenuItem itemSMS = menu.add("Enviar SMS");
        Intent intentSMS = new Intent(Intent.ACTION_VIEW);
        intentSMS.setData(Uri.parse("sms:" + aluno.getTelefone()));
        itemSMS.setIntent(intentSMS);
        MenuItem itemMapa = menu.add("Visualizar no mapa");
        Intent intentMapa = new Intent((Intent.ACTION_VIEW));
        intentMapa.setData(Uri.parse("geo:0,0?q=" +  aluno.getEndereco()));
        itemMapa.setIntent(intentMapa);
        MenuItem itemSite = menu.add("Visitar site");
        Intent intentSite = new Intent(Intent.ACTION_VIEW);
        String site = aluno.getSite();
        if (!site.startsWith("http://")){
            site = "http://" + site;
        }
        intentSite.setData(Uri.parse(site));
        itemSite.setIntent(intentSite);
        MenuItem deletar = menu.add("Deletar");
        deletar.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
            @Override
            public boolean onMenuItemClick(MenuItem item) {
                AlunoDAO dao = new AlunoDAO(MainActivity.this);
                dao.deleta(aluno);
                dao.close();
                carregaLista();
                return false;
            }
        });
    }