TextInputFilter: write your own reusable input filters for UITextField and UITextView

TextInputFilter allows you to write contained and reusable input filters, that can filter and/or transform input as it's typed. The same filters can be used for UITextField or UITextView.

Examples

These examples show the usage of a basic input filter with UITextField, but you can also use the same filter with UITextView.

Writing an input filter

An input filter can respond to input in three ways:

• .accept: input is applied as-is
• .transform: a transformed version of the input is set
• .reject: input is rejected and text is not changed

The input filter will install a delegate that handles the shouldChange... methods, but any other delegate methods are forwarded to the original delegate (even if it was set after the input filter).

This example shows a very simple input filter that just converts input to uppercase.

import TextInputFilter

struct UppercaseInputFilter: TextInputFilter {
    func result(for change: String, appliedTo original: String, replacingRange range: Range<String.Index>, changed: String) -> TextInputFilterResult {
        return .transform(changed.uppercased())
    }
}

Setting the input filter

import TextInputFilter

struct UppercaseInputFilter: TextInputFilter {
    func result(for change: String, appliedTo original: String, replacingRange range: Range<String.Index>, changed: String) -> TextInputFilterResult {
        return .transform(changed.uppercased())
    }
}
...
let textField = UITextField(frame: frame)
textField.setInputFilter(UppercaseInputFilter(), onChange: { print("Changed: \($0)") })
textField.delegate = self // You can still use delegate methods other than textField(_:shouldChangeCharactersIn:replacementString:)

Requirements

TextInputFilter is compatible with Swift 4.x and later, and requires iOS 9.0+

Installation

Copy files

Just drop the files inside the Sources directory anywhere in your own project.

Framework

Download the repo, drag TextInputFilter.xcodeproj into your own project and link the appropriate target for your platform.

CocoaPods

Inside your Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '9.0'

target 'TargetName' do
use_frameworks!
pod 'TextInputFilter'
end

Carthage

Inside your Cartfile:

github "fabiorodella/TextInputFilter"

Swift Package Manager

Inside your Package.swift:

// swift-tools-version:4.0

import PackageDescription

let package = Package(
    name: "TargetName",
    dependencies: [
        .package(url: "https://github.com/fabiorodella/TextInputFilter.git", from: "1.1.0"),
    ],
    targets: [
        .target(
            name: "TargetName",
            dependencies: ["TextInputFilter"]),
    ]
)