|
| 1 | +/* |
| 2 | + Copyright 2017-present The Material Motion Authors. All Rights Reserved. |
| 3 | + |
| 4 | + Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + you may not use this file except in compliance with the License. |
| 6 | + You may obtain a copy of the License at |
| 7 | + |
| 8 | + http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + |
| 10 | + Unless required by applicable law or agreed to in writing, software |
| 11 | + distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + See the License for the specific language governing permissions and |
| 14 | + limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +import UIKit |
| 18 | +import MotionTransitioning |
| 19 | + |
| 20 | +// This example demonstrates how to build a contextual transition. |
| 21 | + |
| 22 | +class ContextualExampleViewController: ExampleViewController { |
| 23 | + |
| 24 | + func didTap(_ tapGesture: UITapGestureRecognizer) { |
| 25 | + let controller = DestinationViewController() |
| 26 | + |
| 27 | + // A contextual transition is provided with information relevant to the transition, such as the |
| 28 | + // view that is being expanded/collapsed. This information can be provided at initialization |
| 29 | + // time if it is unlikely to ever change (e.g. a static view on the screen as in this example). |
| 30 | + // |
| 31 | + // If it's possible for the context to change, then a delegate pattern is a preferred solution |
| 32 | + // because it will allow the delegate to request the new context each time the transition |
| 33 | + // begins. This can be helpful in building photo album transitions, for example. |
| 34 | + // |
| 35 | + // Note that in this example we're populating the contextual transition with the tapped view. |
| 36 | + // Our rudimentary transition will animate the context view to the center of the screen from its |
| 37 | + // current location. |
| 38 | + controller.transitionController.transition = ContextualTransition(contextView: tapGesture.view!) |
| 39 | + |
| 40 | + present(controller, animated: true) |
| 41 | + } |
| 42 | + |
| 43 | + override func viewDidLoad() { |
| 44 | + super.viewDidLoad() |
| 45 | + |
| 46 | + let square = UIView(frame: .init(x: 16, y: 200, width: 128, height: 128)) |
| 47 | + square.autoresizingMask = [.flexibleLeftMargin, .flexibleTopMargin, |
| 48 | + .flexibleRightMargin, .flexibleBottomMargin] |
| 49 | + square.backgroundColor = .blue |
| 50 | + view.addSubview(square) |
| 51 | + |
| 52 | + let circle = UIView(frame: .init(x: 64, y: 400, width: 128, height: 128)) |
| 53 | + circle.autoresizingMask = [.flexibleLeftMargin, .flexibleTopMargin, |
| 54 | + .flexibleRightMargin, .flexibleBottomMargin] |
| 55 | + circle.backgroundColor = .red |
| 56 | + view.addSubview(circle) |
| 57 | + |
| 58 | + square.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(didTap(_:)))) |
| 59 | + circle.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(didTap(_:)))) |
| 60 | + } |
| 61 | + |
| 62 | + override func exampleInformation() -> ExampleInfo { |
| 63 | + return .init(title: type(of: self).catalogBreadcrumbs().last!, |
| 64 | + instructions: "Tap to present a modal transition.") |
| 65 | + } |
| 66 | +} |
| 67 | + |
| 68 | +private class ContextualTransition: NSObject, Transition { |
| 69 | + |
| 70 | + // Store the context for the lifetime of the transition. |
| 71 | + let contextView: UIView |
| 72 | + init(contextView: UIView) { |
| 73 | + self.contextView = contextView |
| 74 | + } |
| 75 | + |
| 76 | + func start(with context: TransitionContext) { |
| 77 | + // A small helper function for creating bi-directional animations. |
| 78 | + // See https://github.com/material-motion/motion-animator-objc for a more versatile |
| 79 | + // bidirectional Core Animation implementation. |
| 80 | + let addAnimationToLayer: (CABasicAnimation, CALayer) -> Void = { animation, layer in |
| 81 | + if context.direction == .backward { |
| 82 | + let swap = animation.fromValue |
| 83 | + animation.fromValue = animation.toValue |
| 84 | + animation.toValue = swap |
| 85 | + } |
| 86 | + layer.add(animation, forKey: animation.keyPath) |
| 87 | + layer.setValue(animation.toValue, forKeyPath: animation.keyPath!) |
| 88 | + } |
| 89 | + |
| 90 | + let snapshotter = TransitionViewSnapshotter(containerView: context.containerView) |
| 91 | + context.defer { |
| 92 | + snapshotter.removeAllSnapshots() |
| 93 | + } |
| 94 | + |
| 95 | + CATransaction.begin() |
| 96 | + CATransaction.setCompletionBlock { |
| 97 | + context.transitionDidEnd() |
| 98 | + } |
| 99 | + |
| 100 | + let fadeIn = CABasicAnimation(keyPath: "opacity") |
| 101 | + fadeIn.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) |
| 102 | + fadeIn.fromValue = 0 |
| 103 | + fadeIn.toValue = 1 |
| 104 | + addAnimationToLayer(fadeIn, context.foreViewController.view.layer) |
| 105 | + |
| 106 | + // We use a snapshot view to accomplish two things: |
| 107 | + // 1) To not affect the context view's state. |
| 108 | + // 2) To allow our context view to appear in front of the fore view controller's view. |
| 109 | + // |
| 110 | + // The provided view snapshotter will automatically hide the snapshotted view and remove the |
| 111 | + // snapshot view upon completion of the transition. |
| 112 | + let snapshotContextView = snapshotter.snapshot(of: contextView, |
| 113 | + isAppearing: context.direction == .backward) |
| 114 | + |
| 115 | + let expand = CABasicAnimation(keyPath: "transform.scale.xy") |
| 116 | + expand.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) |
| 117 | + expand.fromValue = 1 |
| 118 | + expand.toValue = 2 |
| 119 | + addAnimationToLayer(expand, snapshotContextView.layer) |
| 120 | + |
| 121 | + let shift = CASpringAnimation(keyPath: "position") |
| 122 | + shift.damping = 500 |
| 123 | + shift.stiffness = 1000 |
| 124 | + shift.mass = 3 |
| 125 | + shift.duration = 0.5 |
| 126 | + shift.fromValue = snapshotContextView.layer.position |
| 127 | + shift.toValue = CGPoint(x: context.foreViewController.view.bounds.midX, |
| 128 | + y: context.foreViewController.view.bounds.midY) |
| 129 | + addAnimationToLayer(shift, snapshotContextView.layer) |
| 130 | + |
| 131 | + let fadeOut = CABasicAnimation(keyPath: "opacity") |
| 132 | + fadeOut.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut) |
| 133 | + fadeOut.fromValue = 1 |
| 134 | + fadeOut.toValue = 0 |
| 135 | + addAnimationToLayer(fadeOut, snapshotContextView.layer) |
| 136 | + |
| 137 | + CATransaction.commit() |
| 138 | + } |
| 139 | +} |
| 140 | + |
| 141 | +private class DestinationViewController: ExampleViewController { |
| 142 | + |
| 143 | + override func viewDidLoad() { |
| 144 | + super.viewDidLoad() |
| 145 | + |
| 146 | + view.backgroundColor = .primaryColor |
| 147 | + |
| 148 | + view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(didTap))) |
| 149 | + } |
| 150 | + |
| 151 | + func didTap() { |
| 152 | + dismiss(animated: true) |
| 153 | + } |
| 154 | +} |
0 commit comments