private ZXingScannerView zXingScannerView;
private static final int REQUEST_CAMERA = 1;
private EditText txtProduto;
private EditText txtCodigo;
private EditText txtCPF;
private EditText txtData;
private Button btnSalvar;

DBHelper dbHelper = new DBHelper(this);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_tela_cadastro);
    setTitle("Cadastro de utilização");

    txtProduto = findViewById(R.id.txtNomeProduto);
    txtCodigo = findViewById(R.id.txtQRCode);
    txtCPF = findViewById(R.id.txtCPF);
    txtData = findViewById(R.id.txtDataInicio);
    btnSalvar = (Button) findViewById(R.id.btnSalvar);

    btnSalvar.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Toast.makeText(TelaCadastro.this, "Salvo com Sucesso!", Toast.LENGTH_SHORT);

        }
    });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater()
            .inflate(R.menu.tela_registro_ativo, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int itemId = item.getItemId();
    if(itemId == R.id.activity_formulario_aluno_menu_salvar){}
    return super.onOptionsItemSelected(item);
}

public void scan (View view){
    zXingScannerView = new ZXingScannerView(getApplicationContext());
    setContentView(zXingScannerView);
    int currentapiVersion = android.os.Build.VERSION.SDK_INT;
    if (currentapiVersion >= android.os.Build.VERSION_CODES.M) {
        if (checkPermission()) {
            if(zXingScannerView == null) {
                zXingScannerView = new ZXingScannerView(this);
                setContentView(zXingScannerView);
            }
            zXingScannerView.setResultHandler(this);
            zXingScannerView.startCamera();
        } else {
            requestPermission();
        }
    }
}
private boolean checkPermission()
{
    return (ContextCompat.checkSelfPermission(getApplicationContext(), CAMERA) == PackageManager.PERMISSION_GRANTED);
}

private void requestPermission()
{
    ActivityCompat.requestPermissions(this, new String[]{CAMERA}, REQUEST_CAMERA);
}

@Override
protected void onPause() {
    super.onPause();
}


public void handleResult(com.google.zxing.Result result) {
    Toast.makeText(getApplicationContext(),result.getText(),Toast.LENGTH_SHORT).show();
    final String myResult = result.getText();
    Log.d("QRCodeScanner", result.getText());
    Log.d("QRCodeScanner", result.getBarcodeFormat().toString());
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Scan Result");
    builder.setPositiveButton("Ler novamente", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            zXingScannerView.resumeCameraPreview(TelaCadastro.this);
        }
    });
    builder.setMessage(result.getText());
    AlertDialog alert1 = builder.create();
    alert1.show();
    Intent it = new Intent(TelaCadastro.this, TelaCadastro.class);
    it.putExtra("getText", myResult);
    startActivity(it);
}

public static final String TABELA = "Ativo_Utilizacao";
public static final String Ativo_ID = "_id";
public static final String Ativo_Produto = "Produto";
public static final String Ativo_CPF = "CPF";
public static final String Ativo_QRCode = "QRCode";
public static final String Ativo_DataInicio = "DataInicio";
public static final String Ativo_DataFim = "DataFim";

static final String DB_NAME= "App_ATV.db";
static final int DB_VERSION= 1;

private static final String CREATE_TABLE = "Create Table "
        + TABELA + " ("
        + Ativo_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
        + Ativo_Produto + " TEXT NOT NULL, "
        + Ativo_CPF + " TEXT NOT NULL, "
        + Ativo_QRCode + " TEXT NOT NULL, "
        + Ativo_DataInicio + " Date NOT NULL, "
        + Ativo_DataFim + " Date);";

public DBHelper(Context context){
    super(context, DB_NAME,null,DB_VERSION);
}

public SQLiteDatabase db = this.getWritableDatabase();

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS "+ TABELA);
    onCreate(db);
}

public void inserirRegistro (Ativo a) {
    ContentValues cv = new ContentValues();

    cv.put(Ativo_CPF, a.getCpf());
    cv.put(Ativo_Produto, a.getProduto());
    cv.put(Ativo_QRCode, a.getQRCode());
    cv.put(Ativo_DataInicio, a.getDataInicio());
    cv.put(Ativo_DataInicio, a.getDataFim());
    db.insert(TABELA, null, cv);
}