1. Responder chain
Any class that takes UIResponder as the superclass is a responder. UIView and UIControl are subclasses of UIReponder, so all views and all controls are responders.
1. Initial Correspondence
The event will first be passed to the UIApplication object, and then it will be passed to the application's UIWindow. The UIWindow will select an initial corresponding to handle the event. The initial responder will select the following method. 1. For touch events, UIWindow will determine the view touched by the user, and then hand over the event to the gesture recognizer that registers this view or the gesture recognizer with a higher level of the view. As long as there is an identifyer that can handle events, you will not continue to look for it. If not, the touched view is the initial corresponding device and the event will be passed to it.
2. For events generated by the user shaking the device or from the remote control device, it will be passed to the first responder.
If the initial responder does not process time, it passes the event to its parent view (if it exists), or to the view controller (if this view is a view of the view controller). If the view controller does not process the event, it will continue to pass along the hierarchy of the responder chain to the parent view controller (if present).
If there is no view or controller in the entire view level that can handle events, the event will be passed to the application's window. If the window cannot handle events and the application delegate is a subclass of UIResponder, the UIApplication object passes it to the application delegate. Finally, if the application delegate is not a subclass of UIResponder, or does not handle this event, then the event will be discarded.
4 gesture notification methods
#pragma mark - Touch Event Methods
// The user is called when the first time he touches the screen- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
}
// Called when certain events (such as incoming call) cause the gesture to be interrupted- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
}
// Called when the user's finger leaves the screen- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
}
// Triggered when the user's finger moves- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
}
2. Detect scan events
1. Manual detection
//
//
// Swipes
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
// Set detection rangestatic CGFloat const kMinimmGestureLength = 25;
static CGFloat const kMaximmVariance = 5;
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UILabel *label;
@property (nonatomic) CGPoint gestureStartPoint;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
= [touch locationInView:];
}
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint currentPosition = [touch locationInView:];
// Returns the absolute value of a float CGFloat deltaX = fabsf( - );
CGFloat deltaY = fabsf( - );
// After obtaining two increments, determine the distance the user has moved in both directions, and detect whether the user has moved far enough in one direction but not in the other direction to form a swipe action if (deltaX >= kMinimmGestureLength && deltaY <= kMaximmVariance) {
= @"Horizontal swipe detected";
// Erase the text after 2s dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)),
dispatch_get_main_queue(),
^{
= @"";
});
}else if (deltaY >= kMinimmGestureLength && deltaX <= kMaximmVariance){
= @"Vertical swipe detected";
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
= @"";
});
}
}
@end
2. Recognizer detection
//
//
// Swipes
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UILabel *label;
@property (nonatomic) CGPoint gestureStartPoint;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
//Create two gesture recognizers // 1. Horizontal direction identifier UISwipeGestureRecognizer *horizontal = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(reportHorizontalSwipe:)];
= UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight;
[ addGestureRecognizer:horizontal];
// 2. Vertical direction identifier UISwipeGestureRecognizer *vertical = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(reportVerticalSwipe:)];
= UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown;
[ addGestureRecognizer:vertical];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)reportHorizontalSwipe:(UIGestureRecognizer *)recognizer
{
= @"Horizontal swipe detected";
// Erase the text after 2s dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)),
dispatch_get_main_queue(),
^{
= @"";
});
}
- (void)reportVerticalSwipe:(UIGestureRecognizer *)recognizer
{
= @"Vertical swipe detected";
// Erase the text after 2s dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)),
dispatch_get_main_queue(),
^{
= @"";
});
}
@end
3. Achieve multi-finger light swipe
//
//
// Swipes
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UILabel *label;
@property (nonatomic) CGPoint gestureStartPoint;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
for (NSUInteger touchCount = 1; touchCount <= 5; touchCount++) {
//Create two gesture recognizers // 1. Horizontal direction identifier UISwipeGestureRecognizer *horizontal = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(reportHorizontalSwipe:)];
= UISwipeGestureRecognizerDirectionLeft | UISwipeGestureRecognizerDirectionRight;
[ addGestureRecognizer:horizontal];
// 2. Vertical direction identifier UISwipeGestureRecognizer *vertical = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(reportVerticalSwipe:)];
= UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown;
[ addGestureRecognizer:vertical];
}
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (NSString *)descriptionForTouchCount:(NSUInteger)touchCount
{
switch (touchCount) {
case 1:
return @"Single";
case 2:
return @"Double";
case 3:
return @"Triple";
case 4:
return @"Quadruple";
case 5:
return @"Quintuple";
default:
return @"";
}
}
- (void)reportHorizontalSwipe:(UIGestureRecognizer *)recognizer
{
= [NSString stringWithFormat:@"%@ Horizontal swipe detected",[self descriptionForTouchCount:[recognizer numberOfTouches]]];
// Erase the text after 2s dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)),
dispatch_get_main_queue(),
^{
= @"";
});
}
- (void)reportVerticalSwipe:(UIGestureRecognizer *)recognizer
{
= [NSString stringWithFormat:@"%@ Vertical swipe detected",[self descriptionForTouchCount:[recognizer numberOfTouches]]];
// Erase the text after 2s dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)),
dispatch_get_main_queue(),
^{
= @"";
});
}
@end
4. Tap multiple times
//
//
// TapTaps
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UILabel *singleLabel;
@property (weak, nonatomic) IBOutlet UILabel *doubleLabel;
@property (weak, nonatomic) IBOutlet UILabel *tripleLabel;
@property (weak, nonatomic) IBOutlet UILabel *quadrupleLabel;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
// Create 4 click gesture recognizers UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(singleTap)];
= 1;
= 1;
// Attach to view [ addGestureRecognizer:singleTap];
UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTap)];
= 2;
= 1;
[ addGestureRecognizer:doubleTap];
// SingleTap is run when the doubleTap response "failed" [singleTap requireGestureRecognizerToFail:doubleTap];
UITapGestureRecognizer *tripleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tripleTap)];
= 3;
= 1;
[ addGestureRecognizer:tripleTap];
[doubleTap requireGestureRecognizerToFail:tripleTap];
UITapGestureRecognizer *quadrupleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(quadrupleTap)];
= 4;
= 1;
[ addGestureRecognizer:quadrupleTap];
[tripleTap requireGestureRecognizerToFail:quadrupleTap];
}
- (void)singleTap
{
= @"Single Tap Detected";
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
= @"";
});
}
- (void)doubleTap
{
= @"Double Tap Detected";
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
= @"";
});
}
- (void)tripleTap
{
= @"Triple Tap Detected";
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
= @"";
});
}
- (void)quadrupleTap
{
= @"Quadruple Tap Detected";
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
= @"";
});
}
@end
5. Detect kneading and rotation
#import <UIKit/> @interface ViewController : UIViewController<UIGestureRecognizerDelegate> @end
//
//
// PinchMe
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
@interface ViewController ()
@property (strong,nonatomic) UIImageView *imageView;
@end
@implementation ViewController
// Current scaling, previous scalingCGFloat scale,previousScale;
// Current rotation angle, previous rotation angleCGFloat rotation,previousRotation;
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
previousScale = 1;
UIImage *image = [UIImage imageNamed:@"yosemite-meadows"];
= [[UIImageView alloc] initWithImage:image];
// Enable interactive function for images = YES;
= ;
[ addSubview:];
// Create a pinch gesture recognizer UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(doPinch:)];
= self;
[ addGestureRecognizer:pinchGesture];
// Create a rotary gesture recognizer UIRotationGestureRecognizer *rotationGesture = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(doRorate:)];
= self;
[ addGestureRecognizer:rotationGesture];
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
// Allows pinch gestures and rotary gestures to work simultaneously. Otherwise, the gesture recognizer that started first blocks another one return YES;
}
// Transform the image based on the scaling and rotation angle obtained in the gesture recognizer- (void)transformImageView
{
CGAffineTransform t = CGAffineTransformMakeScale(scale * previousScale, scale * previousScale);
t = CGAffineTransformRotate(t, rotation + previousRotation);
= t;
}
- (void)doPinch:(UIPinchGestureRecognizer *)gesture
{
scale = ;
[self transformImageView];
if ( == UIGestureRecognizerStateEnded) {
previousScale = scale * previousScale;
scale = 1;
}
}
- (void)doRorate:(UIRotationGestureRecognizer *)gesture
{
rotation = ;
[self transformImageView];
if ( == UIGestureRecognizerStateEnded) {
previousRotation = rotation + previousRotation;
rotation = 0;
}
}
@end
6. Custom gestures
//
//
// CheckPlease
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
#import ""
#import <UIKit// An important purpose is to make the state property of the gesture recognizer writable. The subclass will use this mechanism to assert that the gesture we are observing has been successfully completed.
// Set detection rangestatic CGFloat const kMinimunCheckMarkAngle = 80;
static CGFloat const kMaximumCheckMarkAngle = 100;
static CGFloat const kMinimumCheckMarkLength = 10;
@implementation CheckMarkRecognizer{
// The first two instance variables provide the previous line segment CGPoint lastPreviousPoint;
CGPoint lastCurrentPoint;
// The length of the drawn line segment CGFloat lineLengthSoFar;
}
// Use lastPreviousPoint and lastCurrentPoint to form the first line segment and form an angle with the second line segment to complete the gesture- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event];
UITouch *touch = [touches anyObject];
CGPoint point = [touch locationInView:];
lastPreviousPoint = point;
lastCurrentPoint = point;
lineLengthSoFar = 0.0;
}
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];
UITouch *touch = [touches anyObject];
CGPoint previousPoint = [touch previousLocationInView:];
CGPoint currentPoint = [touch locationInView:];
CGFloat angle = angleBetweenLines(lastPreviousPoint, lastCurrentPoint, previousPoint, currentPoint);
if (angle >= kMinimunCheckMarkAngle && angle <= kMaximumCheckMarkAngle && lineLengthSoFar > kMinimumCheckMarkLength) {
= UIGestureRecognizerStateRecognized;
}
lineLengthSoFar += distanceBetweenPoints(previousPoint, currentPoint);
lastPreviousPoint = previousPoint;
lastCurrentPoint = currentPoint;
}
@end
//
//
// CheckPlease
//
// Created by Jierism on 16/8/4.
// Copyright © 2016 Jierism. All rights reserved.//
#import ""
#import ""
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIImageView *imageView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
CheckMarkRecognizer *check = [[CheckMarkRecognizer alloc] initWithTarget:self action:@selector(doCheck:)];
[ addGestureRecognizer:check];
= YES;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)doCheck:(CheckMarkRecognizer *)check
{
= NO;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
= YES;
});
}
@end
The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.