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iOS AutoLayout Keyboard Adjuster
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@import UIKit; | |
typedef void (^KeyboardAdjustingBlock)(); | |
@interface KeyboardAdjuster : NSObject | |
@property (nonatomic, assign) BOOL activated; | |
@property (nonatomic, nullable, weak) IBOutlet UIView *targetView; | |
@property (nonatomic, nullable, weak) IBOutlet NSLayoutConstraint *targetConstraint; | |
+ (nonnull instancetype)createWithView:(nonnull UIView *)view constraint:(nonnull NSLayoutConstraint *)constraint; | |
- (nonnull instancetype)initWithShow:(nullable KeyboardAdjustingBlock)show hide:(nullable KeyboardAdjustingBlock)hide NS_DESIGNATED_INITIALIZER; | |
@end |
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#import "KeyboardAdjuster.h" | |
#define SAFE_RUN(block, ...) block ? block(__VA_ARGS__) : nil | |
@interface KeyboardAdjuster () | |
@property (nonatomic, assign) CGFloat advance; | |
@property (nonatomic, assign) BOOL keyboardOnScreen; | |
@end | |
@implementation KeyboardAdjuster | |
#pragma mark - Initialization | |
+ (instancetype)createWithView:(UIView *)view constraint:(NSLayoutConstraint *)constraint | |
{ | |
KeyboardAdjuster *obj = [KeyboardAdjuster new]; | |
obj.targetView = view; | |
obj.targetConstraint = constraint; | |
return obj; | |
} | |
- (instancetype)init | |
{ | |
return [self initWithShow:nil hide:nil]; | |
} | |
- (instancetype)initWithShow:(KeyboardAdjustingBlock)show hide:(KeyboardAdjustingBlock)hide | |
{ | |
if( self = [super init] ) { | |
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardStateChange:) name:UIKeyboardWillShowNotification object:show]; | |
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardStateChange:) name:UIKeyboardWillHideNotification object:hide]; | |
} | |
return self; | |
} | |
- (void)dealloc | |
{ | |
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil]; | |
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil]; | |
} | |
#pragma mark - Notification handler | |
- (void)keyboardStateChange:(NSNotification *)evt | |
{ | |
if( !self.activated ) { | |
return; | |
} | |
KeyboardAdjustingBlock block = evt.object; | |
SAFE_RUN(block); | |
NSDictionary *userInfo = evt.userInfo; | |
CGRect keyboardFrame = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue]; | |
CGRect viewFrame = [self.targetView convertRect:self.targetView.bounds toView:self.targetView.window]; | |
if( [evt.name isEqualToString:UIKeyboardWillShowNotification] && !self.keyboardOnScreen ) { | |
self.keyboardOnScreen = YES; | |
CGRect intersection = CGRectIntersection(viewFrame, keyboardFrame); | |
self.advance = intersection.size.height; | |
self.targetConstraint.constant += self.advance; | |
} else if( [evt.name isEqualToString:UIKeyboardWillHideNotification] ) { | |
self.keyboardOnScreen = NO; | |
self.targetConstraint.constant -= self.advance; | |
self.advance = 0.0; | |
} | |
NSTimeInterval duration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue]; | |
UIViewAnimationCurve curve = [userInfo[UIKeyboardAnimationCurveUserInfoKey] integerValue]; | |
UIViewAnimationOptions options = UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionLayoutSubviews | curve; | |
[UIView animateWithDuration:duration delay:0 options:options animations:^{ | |
[self.targetView.superview setNeedsLayout]; | |
[self.targetView.superview layoutIfNeeded]; | |
} completion:nil]; | |
} | |
@end |
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