Field: Text

This type of field is to make an input text

public function cbInit() {
    // ...

    // Using the "first_name" column
    $this->addText("First Name","first_name");

    // or You can set the first parameter only,
    // then the second parameter will be slug the first parameter as column name
    $this->addText("First Name");

    // Limit characters on index table
    $this->addText("First Name","first_name")->strLimit(20);

    // Limit maximum characters on input
    $this->addText("First Name","first_name")->maxLength(20);

    // Limit minimum characters on input
    $this->addText("First Name","first_name")->minLength(5);

}

Tips. You may combine all those chain options.