components/FlexibleHeader/src/private/MDCStatusBarShifter.m - external/github.com/material-components/material-components-ios - Git at Google

 // Copyright 2015-present the Material Components for iOS authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 // http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #import "MDCStatusBarShifter.h"

 #import "MDCStatusBarShifterDelegate.h"
 #import "MaterialApplication.h"

 #if defined(TARGET_OS_VISION) && TARGET_OS_VISION
 // For code review, use the review queue listed in go/material-visionos-review.
 #define IS_VISIONOS 1
 #else
 #define IS_VISIONOS 0
 #endif

 static NSTimeInterval kStatusBarBecomesInvalidAnimationDuration = 0.2;

 #if !IS_VISIONOS
 // If the time changes then we need to invalidate the status bar.
 // This value is the minimum amount of time we'll wait before invalidating the status bar even
 // after the time has changed in an effort to minimize flickering.
 static NSTimeInterval kMinimumNumberOfSecondsToWaitFor = 3;
 #endif

 // Simple state machine for the shifter:
 //          IsReal => IsSnapshot
 //      IsSnapshot => IsReal, InvalidSnapshot
 // InvalidSnapshot => IsReal
 //
 // In other words, once a snapshot becomes invalid it must go through the real state before it can
 // become a snapshot again.
 //
 // The bulk of this state machine is represented in attemptSnapshotState:

 typedef NS_ENUM(NSInteger, MDCStatusBarShifterState) {
   MDCStatusBarShifterStateRealStatusBar,
   MDCStatusBarShifterStateIsSnapshot,
   MDCStatusBarShifterStateInvalidSnapshot,
 };

 @implementation MDCStatusBarShifter {
   UIView *_statusBarReplicaView;

   // ivars that can invalidate the status bar
   CGRect _originalStatusBarFrame;
   NSTimeInterval _replicaViewTimestamp;
   NSTimeInterval _secondsRemainingInMinute;
   NSTimer *_replicaInvalidatorTimer;

   // While our snapshot is invalid we have slightly different status bar visibility.
   BOOL _prefersStatusBarHiddenWhileInvalid;

   BOOL _isChangingInterfaceOrientation;

   BOOL _prefersStatusBarHidden;
   MDCStatusBarShifterState _snapshotState;

   // The height of the status bar as it is before we do anything to it.
   CGFloat _originalStatusBarHeight;
 }

 - (void)dealloc {
   [_replicaInvalidatorTimer invalidate];
 }

 - (instancetype)init {
   self = [super init];
   if (self) {
     _enabled = YES;
     _snapshottingEnabled = YES;

 #if IS_VISIONOS
     _originalStatusBarHeight = 0.0;
 #else
     _originalStatusBarHeight = [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
     [[NSNotificationCenter defaultCenter]
         addObserver:self
            selector:@selector(statusBarDidChangeFrame)
                name:UIApplicationDidChangeStatusBarFrameNotification
              object:nil];
 #endif
   }
   return self;
 }

 #pragma mark - Notification

 - (void)statusBarDidChangeFrame {
 #if !IS_VISIONOS
   CGFloat statusBarHeight = [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
   _originalStatusBarHeight = statusBarHeight == 0 ? _originalStatusBarHeight : statusBarHeight;
 #endif
 }

 #pragma mark - Private

 // Moves to the invalid state with a status bar animation.
 - (void)invalidateSnapshot {
   [UIView animateWithDuration:kStatusBarBecomesInvalidAnimationDuration
                    animations:^{
                      [self attemptSnapshotState:MDCStatusBarShifterStateInvalidSnapshot];
                    }];
 }

 // Conditions in which the status bar should be invalidated.
 - (BOOL)shouldInvalidateSnapshot {
   // Frames don't match up
   if (!CGRectEqualToRect(_statusBarReplicaView.frame, _originalStatusBarFrame)) {
     return YES;
   }

   // The time has changed
   if (([NSDate timeIntervalSinceReferenceDate] - _replicaViewTimestamp) >
       _secondsRemainingInMinute) {
     return YES;
   }

   return NO;
 }

 // May not necessarily end in the given state.
 - (void)attemptSnapshotState:(MDCStatusBarShifterState)snapshotState {
   if (_snapshotState == snapshotState) {
     // It's likely too good to be true that we're able to stay in the snapshot state, so let's see
     // if we can invalidate the snapshot in any way.
     if (_snapshotState == MDCStatusBarShifterStateIsSnapshot && [self shouldInvalidateSnapshot]) {
       // Frame has become invalid - kill the snapshot.
       [self invalidateSnapshot];
     }
     return;
   }

   // Don't allow changing from invalid to snapshot without going through "real" first.
   if (_snapshotState == MDCStatusBarShifterStateInvalidSnapshot &&
       snapshotState == MDCStatusBarShifterStateIsSnapshot) {
     return;
   }

   // Can't go from real => invalid
   if (_snapshotState == MDCStatusBarShifterStateRealStatusBar &&
       snapshotState == MDCStatusBarShifterStateInvalidSnapshot) {
     return;
   }

   // While disabled, can't leave the real status bar state.
   if (!_enabled && _snapshotState == MDCStatusBarShifterStateRealStatusBar) {
     return;
   }

   // If snapshotting is disabled, then can't go from real => snapshot, but must jump to invalid
   // state.
   if (!_snapshottingEnabled && _snapshotState == MDCStatusBarShifterStateRealStatusBar &&
       snapshotState == MDCStatusBarShifterStateIsSnapshot) {
     snapshotState = MDCStatusBarShifterStateInvalidSnapshot;
   }

   // Invalidate the snapshot if our replica view is currently hidden and we're attempting to take
   // a new snapshot. This handles the case where you're running on an iPhone X in landscape, you
   // hide the header, and then rotate back to portrait. It is at this point that we want to
   // invalidate the snapshot.
   if (_isChangingInterfaceOrientation && snapshotState == MDCStatusBarShifterStateIsSnapshot) {
     snapshotState = MDCStatusBarShifterStateInvalidSnapshot;
   }

   [_replicaInvalidatorTimer invalidate];

   _snapshotState = snapshotState;

   // React to changing the state
   switch (_snapshotState) {
     case MDCStatusBarShifterStateRealStatusBar: {
       // Now showing the real status bar. Remove the replica.
       [_statusBarReplicaView removeFromSuperview];
       _statusBarReplicaView = nil;
       self.prefersStatusBarHidden = NO;
       break;
     }
     case MDCStatusBarShifterStateInvalidSnapshot: {
       // Snapshot is now invalid, show the real status bar.
       [_statusBarReplicaView removeFromSuperview];
       _statusBarReplicaView = nil;
       self.prefersStatusBarHidden = _prefersStatusBarHiddenWhileInvalid;
       break;
     }
     case MDCStatusBarShifterStateIsSnapshot: {
 #if !IS_VISIONOS
       // Take a snapshot of the status bar.
       UIView *snapshotView = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO];
       UIView *clippingView = [[UIView alloc] init];
       CGFloat statusBarHeight =
           [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
       clippingView.frame = CGRectMake(0, 0, snapshotView.frame.size.width, statusBarHeight);
       clippingView.autoresizingMask =
           (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleBottomMargin);
       clippingView.clipsToBounds = YES;
       [clippingView addSubview:snapshotView];
       [self.delegate statusBarShifter:self wantsSnapshotViewAdded:clippingView];

       _statusBarReplicaView = clippingView;
       _originalStatusBarFrame = clippingView.frame;
       _replicaViewTimestamp = [NSDate timeIntervalSinceReferenceDate];

       NSCalendar *calendar = [NSCalendar currentCalendar];
       NSDateComponents *components = [calendar components:NSCalendarUnitSecond
                                                  fromDate:[NSDate date]];
       _secondsRemainingInMinute =
           MAX(kMinimumNumberOfSecondsToWaitFor, (NSTimeInterval)(60 - components.second));

       _replicaInvalidatorTimer = [NSTimer timerWithTimeInterval:_secondsRemainingInMinute
                                                          target:self
                                                        selector:@selector(invalidateSnapshot)
                                                        userInfo:nil
                                                         repeats:NO];
       [[NSRunLoop currentRunLoop] addTimer:_replicaInvalidatorTimer forMode:NSRunLoopCommonModes];
 #endif
       self.prefersStatusBarHidden = YES;
       break;
     }
   }
 }

 - (void)setPrefersStatusBarHidden:(BOOL)prefersStatusBarHidden {
   if (_prefersStatusBarHidden == prefersStatusBarHidden) {
     return;
   }

   _prefersStatusBarHidden = prefersStatusBarHidden;

   [self.delegate statusBarShifterNeedsStatusBarAppearanceUpdate:self];
 }

 #pragma mark - Public

 - (void)setOffset:(CGFloat)offset {
   if (![self canUpdateStatusBarFrame]) {
     return;
   }

   // Bound the status bar range to [0..._originalStatusBarHeight].
   CGFloat statusOffsetY = MIN(_originalStatusBarHeight, offset);

   // Adjust the frame of the status bar.
   if (statusOffsetY > 0) {
     _prefersStatusBarHiddenWhileInvalid = statusOffsetY >= _originalStatusBarHeight;

     if (_snapshotState == MDCStatusBarShifterStateInvalidSnapshot) {
       // If we're in an invalid state then we have to manage the visibility directly.
       [UIView animateWithDuration:kStatusBarBecomesInvalidAnimationDuration
                        animations:^{
                          self.prefersStatusBarHidden = self->_prefersStatusBarHiddenWhileInvalid;
                        }];

     } else {
       [self attemptSnapshotState:MDCStatusBarShifterStateIsSnapshot];
     }
   } else {
     [self attemptSnapshotState:MDCStatusBarShifterStateRealStatusBar];
   }
 }

 - (void)setEnabled:(BOOL)enabled {
   if (_enabled == enabled) {
     return;
   }
   _enabled = enabled;

   if (!_enabled) {
     [UIView animateWithDuration:kStatusBarBecomesInvalidAnimationDuration
                      animations:^{
                        [self attemptSnapshotState:MDCStatusBarShifterStateRealStatusBar];
                      }];
   }
 }

 - (BOOL)canUpdateStatusBarFrame {
 #if IS_VISIONOS
   return NO;
 #else
   CGRect statusBarFrame = [[UIApplication mdc_safeSharedApplication] statusBarFrame];
   CGFloat statusBarHeight = MIN(statusBarFrame.size.width, statusBarFrame.size.height);
   return ((statusBarHeight == _originalStatusBarHeight) || _statusBarReplicaView ||
           _snapshotState == MDCStatusBarShifterStateInvalidSnapshot);
 #endif
 }

 - (BOOL)prefersStatusBarHidden {
   return _prefersStatusBarHidden;
 }

 - (void)interfaceOrientationWillChange {
   _statusBarReplicaView.hidden = YES;
   _isChangingInterfaceOrientation = YES;
 }

 - (void)interfaceOrientationDidChange {
   _statusBarReplicaView.hidden = NO;
   _isChangingInterfaceOrientation = NO;
 }

 - (void)didMoveToWindow {
 #if !IS_VISIONOS
   _originalStatusBarHeight = [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
 #endif
 }

 @end
	// Copyright 2015-present the Material Components for iOS authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#import "MDCStatusBarShifter.h"

	#import "MDCStatusBarShifterDelegate.h"
	#import "MaterialApplication.h"

	#if defined(TARGET_OS_VISION) && TARGET_OS_VISION
	// For code review, use the review queue listed in go/material-visionos-review.
	#define IS_VISIONOS 1
	#else
	#define IS_VISIONOS 0
	#endif

	static NSTimeInterval kStatusBarBecomesInvalidAnimationDuration = 0.2;

	#if !IS_VISIONOS
	// If the time changes then we need to invalidate the status bar.
	// This value is the minimum amount of time we'll wait before invalidating the status bar even
	// after the time has changed in an effort to minimize flickering.
	static NSTimeInterval kMinimumNumberOfSecondsToWaitFor = 3;
	#endif

	// Simple state machine for the shifter:
	// IsReal => IsSnapshot
	// IsSnapshot => IsReal, InvalidSnapshot
	// InvalidSnapshot => IsReal
	//
	// In other words, once a snapshot becomes invalid it must go through the real state before it can
	// become a snapshot again.
	//
	// The bulk of this state machine is represented in attemptSnapshotState:

	typedef NS_ENUM(NSInteger, MDCStatusBarShifterState) {
	MDCStatusBarShifterStateRealStatusBar,
	MDCStatusBarShifterStateIsSnapshot,
	MDCStatusBarShifterStateInvalidSnapshot,
	};

	@implementation MDCStatusBarShifter {
	UIView *_statusBarReplicaView;

	// ivars that can invalidate the status bar
	CGRect _originalStatusBarFrame;
	NSTimeInterval _replicaViewTimestamp;
	NSTimeInterval _secondsRemainingInMinute;
	NSTimer *_replicaInvalidatorTimer;

	// While our snapshot is invalid we have slightly different status bar visibility.
	BOOL _prefersStatusBarHiddenWhileInvalid;

	BOOL _isChangingInterfaceOrientation;

	BOOL _prefersStatusBarHidden;
	MDCStatusBarShifterState _snapshotState;

	// The height of the status bar as it is before we do anything to it.
	CGFloat _originalStatusBarHeight;
	}

	- (void)dealloc {
	[_replicaInvalidatorTimer invalidate];
	}

	- (instancetype)init {
	self = [super init];
	if (self) {
	_enabled = YES;
	_snapshottingEnabled = YES;

	#if IS_VISIONOS
	_originalStatusBarHeight = 0.0;
	#else
	_originalStatusBarHeight = [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
	[[NSNotificationCenter defaultCenter]
	addObserver:self
	selector:@selector(statusBarDidChangeFrame)
	name:UIApplicationDidChangeStatusBarFrameNotification
	object:nil];
	#endif
	}
	return self;
	}

	#pragma mark - Notification

	- (void)statusBarDidChangeFrame {
	#if !IS_VISIONOS
	CGFloat statusBarHeight = [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
	_originalStatusBarHeight = statusBarHeight == 0 ? _originalStatusBarHeight : statusBarHeight;
	#endif
	}

	#pragma mark - Private

	// Moves to the invalid state with a status bar animation.
	- (void)invalidateSnapshot {
	[UIView animateWithDuration:kStatusBarBecomesInvalidAnimationDuration
	animations:^{
	[self attemptSnapshotState:MDCStatusBarShifterStateInvalidSnapshot];
	}];
	}

	// Conditions in which the status bar should be invalidated.
	- (BOOL)shouldInvalidateSnapshot {
	// Frames don't match up
	if (!CGRectEqualToRect(_statusBarReplicaView.frame, _originalStatusBarFrame)) {
	return YES;
	}

	// The time has changed
	if (([NSDate timeIntervalSinceReferenceDate] - _replicaViewTimestamp) >
	_secondsRemainingInMinute) {
	return YES;
	}

	return NO;
	}

	// May not necessarily end in the given state.
	- (void)attemptSnapshotState:(MDCStatusBarShifterState)snapshotState {
	if (_snapshotState == snapshotState) {
	// It's likely too good to be true that we're able to stay in the snapshot state, so let's see
	// if we can invalidate the snapshot in any way.
	if (_snapshotState == MDCStatusBarShifterStateIsSnapshot && [self shouldInvalidateSnapshot]) {
	// Frame has become invalid - kill the snapshot.
	[self invalidateSnapshot];
	}
	return;
	}

	// Don't allow changing from invalid to snapshot without going through "real" first.
	if (_snapshotState == MDCStatusBarShifterStateInvalidSnapshot &&
	snapshotState == MDCStatusBarShifterStateIsSnapshot) {
	return;
	}

	// Can't go from real => invalid
	if (_snapshotState == MDCStatusBarShifterStateRealStatusBar &&
	snapshotState == MDCStatusBarShifterStateInvalidSnapshot) {
	return;
	}

	// While disabled, can't leave the real status bar state.
	if (!_enabled && _snapshotState == MDCStatusBarShifterStateRealStatusBar) {
	return;
	}

	// If snapshotting is disabled, then can't go from real => snapshot, but must jump to invalid
	// state.
	if (!_snapshottingEnabled && _snapshotState == MDCStatusBarShifterStateRealStatusBar &&
	snapshotState == MDCStatusBarShifterStateIsSnapshot) {
	snapshotState = MDCStatusBarShifterStateInvalidSnapshot;
	}

	// Invalidate the snapshot if our replica view is currently hidden and we're attempting to take
	// a new snapshot. This handles the case where you're running on an iPhone X in landscape, you
	// hide the header, and then rotate back to portrait. It is at this point that we want to
	// invalidate the snapshot.
	if (_isChangingInterfaceOrientation && snapshotState == MDCStatusBarShifterStateIsSnapshot) {
	snapshotState = MDCStatusBarShifterStateInvalidSnapshot;
	}

	[_replicaInvalidatorTimer invalidate];

	_snapshotState = snapshotState;

	// React to changing the state
	switch (_snapshotState) {
	case MDCStatusBarShifterStateRealStatusBar: {
	// Now showing the real status bar. Remove the replica.
	[_statusBarReplicaView removeFromSuperview];
	_statusBarReplicaView = nil;
	self.prefersStatusBarHidden = NO;
	break;
	}
	case MDCStatusBarShifterStateInvalidSnapshot: {
	// Snapshot is now invalid, show the real status bar.
	[_statusBarReplicaView removeFromSuperview];
	_statusBarReplicaView = nil;
	self.prefersStatusBarHidden = _prefersStatusBarHiddenWhileInvalid;
	break;
	}
	case MDCStatusBarShifterStateIsSnapshot: {
	#if !IS_VISIONOS
	// Take a snapshot of the status bar.
	UIView *snapshotView = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO];
	UIView *clippingView = [[UIView alloc] init];
	CGFloat statusBarHeight =
	[UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
	clippingView.frame = CGRectMake(0, 0, snapshotView.frame.size.width, statusBarHeight);
	clippingView.autoresizingMask =
	(UIViewAutoresizingFlexibleWidth \| UIViewAutoresizingFlexibleBottomMargin);
	clippingView.clipsToBounds = YES;
	[clippingView addSubview:snapshotView];
	[self.delegate statusBarShifter:self wantsSnapshotViewAdded:clippingView];

	_statusBarReplicaView = clippingView;
	_originalStatusBarFrame = clippingView.frame;
	_replicaViewTimestamp = [NSDate timeIntervalSinceReferenceDate];

	NSCalendar *calendar = [NSCalendar currentCalendar];
	NSDateComponents *components = [calendar components:NSCalendarUnitSecond
	fromDate:[NSDate date]];
	_secondsRemainingInMinute =
	MAX(kMinimumNumberOfSecondsToWaitFor, (NSTimeInterval)(60 - components.second));

	_replicaInvalidatorTimer = [NSTimer timerWithTimeInterval:_secondsRemainingInMinute
	target:self
	selector:@selector(invalidateSnapshot)
	userInfo:nil
	repeats:NO];
	[[NSRunLoop currentRunLoop] addTimer:_replicaInvalidatorTimer forMode:NSRunLoopCommonModes];
	#endif
	self.prefersStatusBarHidden = YES;
	break;
	}
	}
	}

	- (void)setPrefersStatusBarHidden:(BOOL)prefersStatusBarHidden {
	if (_prefersStatusBarHidden == prefersStatusBarHidden) {
	return;
	}

	_prefersStatusBarHidden = prefersStatusBarHidden;

	[self.delegate statusBarShifterNeedsStatusBarAppearanceUpdate:self];
	}

	#pragma mark - Public

	- (void)setOffset:(CGFloat)offset {
	if (![self canUpdateStatusBarFrame]) {
	return;
	}

	// Bound the status bar range to [0..._originalStatusBarHeight].
	CGFloat statusOffsetY = MIN(_originalStatusBarHeight, offset);

	// Adjust the frame of the status bar.
	if (statusOffsetY > 0) {
	_prefersStatusBarHiddenWhileInvalid = statusOffsetY >= _originalStatusBarHeight;

	if (_snapshotState == MDCStatusBarShifterStateInvalidSnapshot) {
	// If we're in an invalid state then we have to manage the visibility directly.
	[UIView animateWithDuration:kStatusBarBecomesInvalidAnimationDuration
	animations:^{
	self.prefersStatusBarHidden = self->_prefersStatusBarHiddenWhileInvalid;
	}];

	} else {
	[self attemptSnapshotState:MDCStatusBarShifterStateIsSnapshot];
	}
	} else {
	[self attemptSnapshotState:MDCStatusBarShifterStateRealStatusBar];
	}
	}

	- (void)setEnabled:(BOOL)enabled {
	if (_enabled == enabled) {
	return;
	}
	_enabled = enabled;

	if (!_enabled) {
	[UIView animateWithDuration:kStatusBarBecomesInvalidAnimationDuration
	animations:^{
	[self attemptSnapshotState:MDCStatusBarShifterStateRealStatusBar];
	}];
	}
	}

	- (BOOL)canUpdateStatusBarFrame {
	#if IS_VISIONOS
	return NO;
	#else
	CGRect statusBarFrame = [[UIApplication mdc_safeSharedApplication] statusBarFrame];
	CGFloat statusBarHeight = MIN(statusBarFrame.size.width, statusBarFrame.size.height);
	return ((statusBarHeight == _originalStatusBarHeight) \|\| _statusBarReplicaView \|\|
	_snapshotState == MDCStatusBarShifterStateInvalidSnapshot);
	#endif
	}

	- (BOOL)prefersStatusBarHidden {
	return _prefersStatusBarHidden;
	}

	- (void)interfaceOrientationWillChange {
	_statusBarReplicaView.hidden = YES;
	_isChangingInterfaceOrientation = YES;
	}

	- (void)interfaceOrientationDidChange {
	_statusBarReplicaView.hidden = NO;
	_isChangingInterfaceOrientation = NO;
	}

	- (void)didMoveToWindow {
	#if !IS_VISIONOS
	_originalStatusBarHeight = [UIApplication mdc_safeSharedApplication].statusBarFrame.size.height;
	#endif
	}

	@end