Enable or disable Next button on qt installer framework.

[Nguyen Thang Phong]

I using QT Installer Framework version 4.8.
I tried enable Next button with the code below:

            var loginObj = widget.findChild("btnLogin");
            var usernameObj = widget.findChild("txtUsername");
            var passwordObj = widget.findChild("txtPassword");

            if (loginObj != null) {
                loginObj.clicked.connect(() => {
                    var username = usernameObj.text;
                    var password = passwordObj.text;

                    if (username != null && password != null) {
                        var hashValue = mymodule.hashPassword(password);
                        
                        if (mymodule.verifyAccount(username, hashValue) == true) {
                            var isOk = QMessageBox.information("", "Success", "Login successful !", QMessageBox.Ok);
                            
                            if (isOk == QMessageBox.Ok) {
                                widget.complete = true;
                            }
                        } else {
                            QMessageBox.critical("", "Error", "Invalid username or password !");
                        }
                    }
                });
            }

I debug and display widget.complete have set to true but Next button is not enabled.
Help me the solution.