Skip to content

Added extension for UIView constrain center #21

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
75 changes: 75 additions & 0 deletions Sources/YCoreUI/Extensions/UIKit/UIView+constrainCenter.swift
Original file line number Diff line number Diff line change
@@ -0,0 +1,75 @@
//
// UIView+constrainCenter.swift
// YCoreUI
//
// Created by Dharmik Ghelani on 20/10/22.
// Copyright © 2022 Y Media Labs. All rights reserved.
//

import UIKit

extension UIView {
/// Center alignment options
public struct Center: OptionSet {
/// corresponding raw value
public let rawValue: UInt

/// center X
public static let x = Center(rawValue: 1 << 0)
/// center Y
public static let y = Center(rawValue: 1 << 1)
/// all (both center X and center Y)
public static let all: Center = [.x, .y]

/// Creates the new `Center` option set from the given raw value.
/// - Parameter rawValue: the raw value of `Center` option set to create
public init(rawValue: UInt) {
self.rawValue = rawValue
}
}

/// Constrain the center of the receiving view with the center of another view
/// - Parameters:
/// - center: which center attributes to constrain (default `.all`)
/// - view2: view or layout guide to constrain to (pass `nil` to constrain to superview)
/// - relation: relation to evaluate (towards view2) (default `.equal`)
/// - offset: offset to apply relative to view2.center (default `.zero`)
/// - priority: constraint priority (default `.required`)
/// - isActive: whether to activate the constraints or not (default `true`)
/// - Returns: dictionary of constraints created, keyed by `.centerX, .centerY`
public func constrainCenter(
_ center: Center = .all,
to view2: Anchorable? = nil,
relatedBy relation: NSLayoutConstraint.Relation = .equal,
offset: UIOffset = .zero,
priority: UILayoutPriority = .required,
isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint] {
var constraints: [NSLayoutConstraint.Attribute: NSLayoutConstraint] = [:]
let otherView: Anchorable! = view2 ?? superview

if center.contains(.x) {
constraints[.centerX] = constrain(
.centerXAnchor,
to: otherView.centerXAnchor,
relatedBy: relation,
constant: offset.horizontal,
priority: priority,
isActive: isActive
)
}

if center.contains(.y) {
constraints[.centerY] = constrain(
.centerYAnchor,
to: otherView.centerYAnchor,
relatedBy: relation,
constant: offset.vertical,
priority: priority,
isActive: isActive
)
}

return constraints
}
}
Original file line number Diff line number Diff line change
@@ -0,0 +1,84 @@
//
// UIView+constrainCenterTests.swift
// YCoreUI
//
// Created by Dharmik Ghelani on 20/10/22.
// Copyright © 2022 Y Media Labs. All rights reserved.
//

import XCTest
@testable import YCoreUI

final class UIViewConstrainCenterTests: XCTestCase {
func testCenterX() {
let (sut, offset) = makeSUT()

let constraints = sut.view1.constrainCenter(.x, offset: offset)
let centerXConstraint = constraints[.centerX]

XCTAssertFalse(sut.view1.translatesAutoresizingMaskIntoConstraints)
XCTAssertEqual(constraints.count, 1)
XCTAssertNotNil(centerXConstraint)
XCTAssertEqual(centerXConstraint?.firstItem as? UIView, sut.view1)
XCTAssertEqual(centerXConstraint?.firstAttribute, .centerX)
XCTAssertEqual(centerXConstraint?.secondItem as? UIView, sut)
XCTAssertEqual(centerXConstraint?.secondAttribute, .centerX)
XCTAssertEqual(centerXConstraint?.constant, offset.horizontal)
}

func testCenterY() {
let (sut, offset) = makeSUT()

let constraints = sut.view1.constrainCenter(.y, offset: offset)
let centerYConstraint = constraints[.centerY]

XCTAssertFalse(sut.view1.translatesAutoresizingMaskIntoConstraints)
XCTAssertEqual(constraints.count, 1)
XCTAssertNotNil(centerYConstraint)
XCTAssertEqual(centerYConstraint?.firstItem as? UIView, sut.view1)
XCTAssertEqual(centerYConstraint?.firstAttribute, .centerY)
XCTAssertEqual(centerYConstraint?.secondItem as? UIView, sut)
XCTAssertEqual(centerYConstraint?.secondAttribute, .centerY)
XCTAssertEqual(centerYConstraint?.constant, offset.vertical)
}

func testCenterBoth() {
let (sut, offset) = makeSUT()

let constraints = sut.view1.constrainCenter(offset: offset)

let anchorAttributes: [
(NSLayoutConstraint.Attribute, CGFloat)
] = [
(.centerX, offset.horizontal),
(.centerY, offset.vertical)
]

XCTAssertFalse(sut.view1.translatesAutoresizingMaskIntoConstraints)
XCTAssertEqual(constraints.count, 2)

anchorAttributes.forEach {
let constraint = constraints[$0.0]
XCTAssertNotNil(constraint)
XCTAssertEqual(constraint?.firstItem as? UIView, sut.view1)
XCTAssertEqual(constraint?.firstAttribute, $0.0)
XCTAssertEqual(constraint?.secondItem as? UIView, sut)
XCTAssertEqual(constraint?.secondAttribute, $0.0)
XCTAssertEqual(constraint?.constant, $0.1)
}
}
}

extension UIViewConstrainCenterTests {
func makeSUT(
file: StaticString = #filePath,
line: UInt = #line
) -> (MockLayoutContainer, UIOffset) {
let container = MockLayoutContainer()
let offset = UIOffset(horizontal: 30, vertical: 20)

trackForMemoryLeak(container, file: file, line: line)

return (container, offset)
}
}