ObjectForm - SwiftGit

Textfield

ObjectForm

November 23, 2023

A simple yet powerful library to build form for your class models.

Motivations

I found most form libraries for swift are too complicated to bootstrap a simple project. So I write ObjectForm to make it dead simple for building forms and binding model classes.

ObjectForm doesn’t fight with you to write UIKit code. By design, it is simple to understand and extend. If you follow the example project carefully, you would find it easy to fit in your Swift project.

This project has no dependency of any other library.

Application

In my application (a personal finance app), I use ObjectForm to make forms for multiple classes as well as different variants for the same class, which saves me from writing duplicate code.

Features

Bind class model to form rows
Automatic keyboards types according to model types
Form rows are type safe
Fully customizable form validation rules
A list of built-in UITableViewCell to support multiple types
Work amazingly well with your UITableView code

Requirements

iOS >= 11.0

Usage

Copy sources

Copy files under /Sources into your project.

Carthage (Coming soon)
Swift Package Manager

Click “Files -> Swift Package Manager -> Add Package Dependency…” in Xcode’s menu
Search “https://github.com/haojianzong/ObjectForm“.
Select “master” branch or input “Next major version”

Available Rows & Cells

Rows

StringRow: Row to support string input, full keyboard
DoubleRow: Row to support number input, numeric keyboard
DecimalRow: Row to support number input, numeric keyboard, with NSDecimalNumber type
DateRow: Row to bind Date value

Cells

TextViewInputCell: text input cell
SelectInputCell: support selection, provided by CollectionPicker
TextViewVC: A view controller with UITextView to input long text
ButtonCell: Show a button in the form
TypedInputCell: Generic cell to support type binding
FormInputCell: The base class for all cells

Tutorials

You can follow ObjectFormExample in ObjectFormExample to learn how to build a simple form with a class model.

Binding Model to Form


                                              
                                                class FruitFormData: NSObject, FormDataSource {

// Bind your custom model

typealias BindModel = Fruit

var basicRows: [BaseRow] = []
func numberOfSections() -> Int {…}

func numberOfRows(at section: Int) -> Int {…}

func row(at indexPath: IndexPath) -> BaseRow {…}
self.bindModel = fruit
basicRows.append(StringRow(title: “Name”,

icon: “”,

kvcKey: “name”,

value: fruit.name ?? “”,

placeholder: nil,

validator: nil))
// Row are type safe

basicRows.append(DoubleRow(title: “Price”,

icon: “”,

kvcKey: “price”,

value: fruit.price,

placeholder: “”,

validator: nil))
// You can build as many rows as you want

basicRows.append(TextViewRow(title: “Note”,

kvcKey: “note”,

value: fruit.note ?? “-“))

}

}

Showing FormDataSource in a UITableView


                                              
                                                class FruitFormVC: UIViewController {

private let dataSource: FruitFormData

}
extension FruitFormVC: UITableViewDataSource {

func numberOfSections(in tableView: UITableView) -> Int {

return dataSource.numberOfSections()

}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

dataSource.numberOfRows(at: section)

}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let row = dataSource.row(at: indexPath)

row.baseCell.setup(row)

row.baseCell.delegate = self

return row.baseCell

}

}

Listening to Cell Value Change


                                              
                                                extension FruitFormVC: FormCellDelegate {

func cellDidChangeValue(_ cell: UITableViewCell, value: Any?) {

let indexPath = tableView.indexPath(for: cell)!

_ = dataSource.updateItem(at: indexPath, value: value)

}

}

Data Validation

By providing a validation block when building a row, you can provide any validaiton rules.


                                              
                                                basicRows.append(StringRow(title: “Name”,

icon: “”,

kvcKey: “name”,

value: fruit.name ?? “”,

placeholder: nil,

validator: {

// Custom rules for row validation

return !(fruit.name?.isEmpty ?? true)
}))


                                              
                                                @objc private func saveButtonTapped() {

guard dataSource.validateData() else {

tableView.reloadData()

return

}
navigationController?.popViewController(animated: true)

}

Row Type Safety

Since a form row use key-value-coding to update its bind model, it is important to keep the row value type the same as the object’s variable type. ObjectForm enforces type safe. Every row must implement the following method:

open override func isValueMatchRowType(value: Any) -> Bool

This is already implemented by built-in generic rows, for example, TypedRow<T> and SelectRow<T>.

Make Your Own Row

Making your own row and cell is easy. You have 2 options:

Create concrete type using TypedRow


                                              
                                                typealias StringRow = TypedRow<String>

Subclass BaseRow


                                              
                                                class TextViewRow: BaseRow {
public override var baseCell: FormInputCell {

return cell

}
public override var baseValue: CustomStringConvertible? {

get { return value }

set { value = newValue as? String }

}
var value: String?
var cell: TextViewInputCell
open override func isValueMatchRowType(value: Any) -> Bool {

let t = type(of: value)

return String.self == t

}
override var description: String {

return “<TextViewRow> \(title ?? “”)”

}
required init(title: String, kvcKey: String, value: String?) {

self.cell = TextViewInputCell()
super.init()
self.title = title

self.kvcKey = kvcKey

self.value = value

self.placeholder = nil

}

}