ARGrowingTextView

Auto-growing multi-line UITextView with built-in Markdown support. Similar to the text input field in iMessage — the view automatically adjusts its height as the user types.

Powered by ARMarkdownTextStorage for real-time Markdown rendering.

Features

• Auto-resizing — height grows and shrinks with content, constrained by min/max lines or explicit point values
• Height change animation — smooth animated transitions with ARAnimationContext to synchronize surrounding layout changes
• Placeholder — built-in placeholder label with customizable color
• Markdown — live rendering of bold, italic, strikethrough, and underline via MarkdownTextStorage
• Smart paste — RTF, HTML, plain text, and URL paste automatically converted to Markdown symbols
• Smart copy — copies selected text with Markdown formatting preserved
• Style menu — context menu actions for Bold, Italic, Underline, and Strikethrough on selected text
• Image paste — images from the pasteboard forwarded through userDidPaste(images:) delegate callback
• Dynamic Type — responds to UIContentSizeCategory changes and updates font accordingly
• UITextView proxy — all commonly used UITextView properties exposed directly on ARGrowingTextView

Requirements

• iOS 13.0+
• Swift 5.10+
• ARMarkdownTextStorage >= 2.0.0 (resolved automatically)

Installation

Swift Package Manager

Add the dependency to your Package.swift:

dependencies: [
    .package(url: "https://github.com/AppleArealidea/ARGrowingTextView.git",
             .upToNextMajor(from: "1.0.0"))
]

Then add "ARGrowingTextView" to the target's dependencies array.

Or in Xcode: File → Add Package Dependencies… and paste the repository URL.

Usage

Basic setup

import ARGrowingTextView

let textView = ARGrowingTextView()
textView.minNumberOfLines = 1
textView.maxNumberOfLines = 6
textView.placeholder = "Type a message…"
textView.font = .preferredFont(forTextStyle: .body)
textView.delegate = self

Height constraints

You can limit growth by number of lines:

textView.minNumberOfLines = 1
textView.maxNumberOfLines = 5

Or by explicit point values:

textView.minHeight = 36
textView.maxHeight = 200

Animated height changes

Enable or disable animation and set its duration:

textView.animateHeightChange = true   // default
textView.animationDuration = 0.1      // default

Use ARAnimationContext in the delegate to run your own animations in sync with the height transition:

func growingTextView(_ growingTextView: ARGrowingTextView,
                     changeHeightWith diff: CGFloat,
                     animationContext: ARAnimationContext) {
    animationContext.animate {
        // adjust your bottom constraint, table view inset, etc.
        self.bottomConstraint.constant += diff
        self.view.layoutIfNeeded()
    }
}

Handling pasted images

func userDidPaste(images: [UIImage]) {
    // process pasted images
}

Accessing the internal UITextView

For properties not directly proxied, use internalTextView:

textView.internalTextView.autocorrectionType = .no

Delegate

ARGrowingTextViewDelegate provides the following optional callbacks:

Method	Description
growingTextViewShouldBeginEditing(_:)	Whether editing should begin
growingTextViewShouldEndEditing(_:)	Whether editing should end
growingTextViewDidBeginEditing(_:)	Editing started
growingTextViewDidEndEditing(_:)	Editing ended
growingTextView(_:shouldChangeTextIn:replacementText:)	Intercept text changes
growingTextViewDidChange(_:)	Text content changed
growingTextView(_:willChangeHeight:)	Height is about to change
growingTextView(_:changeHeightWith:animationContext:)	Height is changing — use the context to add synchronized animations
growingTextView(_:didChangeHeight:)	Height change completed
growingTextViewDidChangeSelection(_:)	Text selection changed
growingTextViewShouldReturn(_:)	Return key tapped — return true to resign first responder
userDidPaste(images:)	User pasted images from the pasteboard

Migrating from HPGrowingTextView

ARGrowingTextView preserves the same architectural approach (a UIView wrapping an internal UITextView) and keeps familiar API names, so migration is mostly mechanical.

What stays the same

HPGrowingTextView (Obj-C)	ARGrowingTextView (Swift)
maxNumberOfLines / minNumberOfLines	maxNumberOfLines / minNumberOfLines
maxHeight / minHeight	maxHeight / minHeight
animateHeightChange	animateHeightChange
animationDuration	animationDuration
.internalTextView	.internalTextView
text, font, textColor, textAlignment, selectedRange, editable, dataDetectorTypes, returnKeyType	Same — proxied directly
All growingTextView… delegate methods	Same names, Swift syntax

What changed

Change	Details
Language	Objective-C → Swift 5.10+
Min deployment	iOS 4+ → iOS 13+
Installation	CocoaPods → Swift Package Manager
Layout	Frame-based → Auto Layout (add as subview and pin with constraints)
Height animation callback	willChangeHeight: was called inside the animation block. Now use changeHeightWith:animationContext: and call animationContext.animate { … } to synchronize your layout changes.
Delegate protocol	HPGrowingTextViewDelegate → ARGrowingTextViewDelegate

What's new

• Markdown — live bold, italic, strikethrough, and underline rendering via MarkdownTextStorage
• Smart paste / copy — RTF, HTML, and URL paste converted to Markdown; copy preserves formatting
• Style menu — context menu actions (Bold, Italic, Underline, Strikethrough) on selected text
• Image paste — userDidPaste(images:) delegate callback
• Placeholder — built-in placeholder label with customizable color
• Dynamic Type — automatic font updates on UIContentSizeCategory changes

Quick example

- #import "HPGrowingTextView.h"
+ import ARGrowingTextView

- HPGrowingTextView *textView = [[HPGrowingTextView alloc] initWithFrame:rect];
- textView.minNumberOfLines = 1;
- textView.maxNumberOfLines = 5;
+ let textView = ARGrowingTextView()
+ textView.minNumberOfLines = 1
+ textView.maxNumberOfLines = 5

  // Height animation
- - (void)growingTextView:(HPGrowingTextView *)gTV willChangeHeight:(float)height {
-     [UIView animateWithDuration:0.1 animations:^{
-         // adjust layout
-     }];
- }
+ func growingTextView(_ growingTextView: ARGrowingTextView,
+                      changeHeightWith diff: CGFloat,
+                      animationContext: ARAnimationContext) {
+     animationContext.animate {
+         self.bottomConstraint.constant += diff
+         self.view.layoutIfNeeded()
+     }
+ }

Acknowledgments

ARGrowingTextView is inspired by HPGrowingTextView by Hans Pinckaers — a pioneering Objective-C library (2011, 2000+ stars) that introduced the concept of an auto-growing UITextView for iOS. The original project has been archived since 2019.

ARGrowingTextView is a modern reimagining in Swift, adding Markdown support, smart paste/copy, style menus, image handling, Dynamic Type, and full Auto Layout integration.

License

MIT © 2023 Areal