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你真的了解UIEvent、UITouch吗？
小程序：扫一扫查出行【扫一扫了解最新限行尾号】
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一：首先查看一下关于UIEvent的定义
//事件类型
typedef NS_ENUM(NSInteger, UIEventType) {
UIEventTypeTouches,
UIEventTypeMotion,
UIEventTypeRemoteControl,
}; // 触摸事件的类型
typedef NS_ENUM(NSInteger, UIEventSubtype) { UIEventSubtypeNone = ,
//摇晃
UIEventSubtypeMotionShake = ,
//播放
UIEventSubtypeRemoteControlPlay = ,
//暂停
UIEventSubtypeRemoteControlPause = ,
//停止
UIEventSubtypeRemoteControlStop = ,
//播放和暂停切换
UIEventSubtypeRemoteControlTogglePlayPause = ,
//下一首
UIEventSubtypeRemoteControlNextTrack = ,
//上一首
UIEventSubtypeRemoteControlPreviousTrack = ,
//开始后退
UIEventSubtypeRemoteControlBeginSeekingBackward = ,
//结束后退
UIEventSubtypeRemoteControlEndSeekingBackward = ,
//开始快进
UIEventSubtypeRemoteControlBeginSeekingForward = ,
//结束快进
UIEventSubtypeRemoteControlEndSeekingForward = ,
}; NS_CLASS_AVAILABLE_IOS(2_0) @interface UIEvent : NSObject
//事件类型
@property(nonatomic,readonly) UIEventType type NS_AVAILABLE_IOS(3_0);
// 触摸事件的类型
@property(nonatomic,readonly) UIEventSubtype subtype NS_AVAILABLE_IOS(3_0); //事件的时间戳
@property(nonatomic,readonly) NSTimeInterval timestamp; //所有的触摸
- (nullable NSSet <UITouch *> *)allTouches;
//获得UIWindow的触摸
- (nullable NSSet <UITouch *> *)touchesForWindow:(UIWindow *)window;
//获得UIView的触摸
- (nullable NSSet <UITouch *> *)touchesForView:(UIView *)view;
//获得事件中特定手势的触摸
- (nullable NSSet <UITouch *> *)touchesForGestureRecognizer:(UIGestureRecognizer *)gesture NS_AVAILABLE_IOS(3_2); //会将丢失的触摸放到一个新的 UIEvent 数组中，你可以用 coalescedTouchesForTouch(_:) 方法来访问
- (nullable NSArray <UITouch *> *)coalescedTouchesForTouch:(UITouch *)touch NS_AVAILABLE_IOS(9_0);
//辅助UITouch的触摸，预测发生了一系列主要的触摸事件。这些预测可能不完全匹配的触摸的真正的行为，因为它的移动，所以他们应该被解释为一个估计。
- (nullable NSArray <UITouch *> *)predictedTouchesForTouch:(UITouch *)touch NS_AVAILABLE_IOS(9_0); @end
UIEvent是代表iOS系统中的一个事件,一个事件包含一个或多个的UITouch；UIEvent分为三类:UIEventTypeTouches触摸事件(通过触摸、手势进行触发,例如手指点击、缩放)、UIEventTypeMotion运动事件,通过加速器进行触发（例如手机晃动）、UIEventTypeRemoteControl远程控制事件通过其他远程设备触发（例如耳机控制按钮）；
知识点1：在iOS中并不是所有的类都能处理接收并事件，只有继承自UIResponder类的对象才能处理事件，（如我们常用的UIView、UIViewController、UIApplication都继承自UIResponder，它们都能接收并处理事件）。在UIResponder中定义了上面三类事件相关的处理方法：
触摸事件：
(void)touchesBegan:(NSSet )touches withEvent:(UIEvent )event;
一根或多根手指开始触摸屏幕时执行； (void)touchesMoved:(NSSet )touches withEvent:(UIEvent )event;
一根或多根手指在屏幕上移动时执行，注意此方法在移动过程中会重复调用； (void)touchesEnded:(NSSet )touches withEvent:(UIEvent )event;
一根或多根手指触摸结束离开屏幕时执行； (void)touchesCancelled:(NSSet )touches withEvent:(UIEvent )event;
触摸意外取消时执行（例如正在触摸时打入电话）；
运动事件：
(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event NS_AVAILABLE_IOS(3_0);
运动开始时执行； (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event NS_AVAILABLE_IOS(3_0);
运动结束后执行； (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event NS_AVAILABLE_IOS(3_0);
运动被意外取消时执行；
远程控制事件：
(void)remoteControlReceivedWithEvent:(UIEvent *)event NS_AVAILABLE_IOS(4_0);
接收到远程控制消息时执行；
知识点2：iOS「摇一摇」功能的实现（运动事件的运用）
- (void)viewDidLoad {
[super viewDidLoad];
// 设置允许摇一摇功能
[UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;
// 并让自己成为第一响应者
[self becomeFirstResponder];
return;
}
//摇一摇相关方法
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event {
NSLog(@"开始摇动");
return;
}
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event {
NSLog(@"取消摇动");
return;
}
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
if (event.subtype == UIEventSubtypeMotionShake) { // 判断是否是摇动结束
NSLog(@"摇动结束");
}
return;
}
另外:监听运动事件前提，监听对象必须成为第一响应者；在模拟器中运行时，可以通过「Hardware」-「Shake Gesture」来测试「摇一摇」功能
知识点3：一个摇动随机图片显示的实例（运动事件的运用）
KCImageView.m
#import "KCImageView.h"
#define kImageCount 3
@implementation KCImageView
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
self.image = [self getImage];
}
return self;
}
#pragma mark 设置控件可以成为第一响应者
- (BOOL)canBecomeFirstResponder{
return YES;
}
#pragma mark 运动开始
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event{
//这里只处理摇晃事件
if (motion == UIEventSubtypeMotionShake) {
self.image = [self getImage];
}
}
#pragma mark 运动结束
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event{
}
#pragma mark 随机取得图片
- (UIImage *)getImage{
int index = arc4random() % kImageCount;
NSString *imageName = [NSString stringWithFormat:@"avatar%i.png",index];
UIImage *image = [UIImage imageNamed:imageName];
return image;
}
@end
KCShakeViewController.m
#import "KCShakeViewController.h"
#import "KCImageView.h"
@interface KCShakeViewController (){
KCImageView *_imageView;
}
@end
@implementation KCShakeViewController
- (void)viewDidLoad {
[super viewDidLoad];
}
#pragma mark 视图显示时让控件变成第一响应者
- (void)viewDidAppear:(BOOL)animated{
_imageView = [[KCImageView alloc] initWithFrame:[UIScreen mainScreen].applicationFrame];
_imageView.userInteractionEnabled = true;
[self.view addSubview:_imageView];
[_imageView becomeFirstResponder];
}
#pragma mark 视图不显示时注销控件第一响应者的身份
- (void)viewDidDisappear:(BOOL)animated{
[_imageView resignFirstResponder];
}
@end
知识点4：远程控制事件的运用
iOS远程控制事件，是通过其他远程设备触发的（比如耳机控制按钮），iOS远程控制事件相关的只有-(void)remoteControlReceivedWithEvent:(UIEvent *)event；监听远程控制事件的前提：启动远程事件接收，调用[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];UI控件同样要求必须成为第一响应者【使用参考运动事件】，但如果是视图控制器或UIApplication，就没有要求成为第一响应者，应用程序必须是 当前音频额控制者，目前iOS7给我们的远程控制权限仅限于音频控制；
一个关于音乐远程控制实例：
#import "ViewController.h"
@interface ViewController (){
UIButton *_playButton;
BOOL _isPlaying;
}
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
[self initLayout];
}
- (BOOL)canBecomeFirstResponder{
return NO;
}
- (void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
NSURL *url = [NSURL URLWithString:@"http://stream.jewishmusicstream.com:8000"];
_player = [[AVPlayer alloc] initWithURL:url];
}
#pragma mark 远程控制事件
- (void)remoteControlReceivedWithEvent:(UIEvent *)event{
if(event.type == UIEventTypeRemoteControl){
switch (event.subtype) {
case UIEventSubtypeRemoteControlPlay:
[_player play];
_isPlaying = true;
break;
case UIEventSubtypeRemoteControlTogglePlayPause:
[self btnClick:_playButton];
break;
case UIEventSubtypeRemoteControlNextTrack:
NSLog(@"Next...");
break;
case UIEventSubtypeRemoteControlPreviousTrack:
NSLog(@"Previous...");
break;
case UIEventSubtypeRemoteControlBeginSeekingForward:
NSLog(@"Begin seek forward...");
break;
case UIEventSubtypeRemoteControlEndSeekingForward:
NSLog(@"End seek forward...");
break;
case UIEventSubtypeRemoteControlBeginSeekingBackward:
NSLog(@"Begin seek backward...");
break;
case UIEventSubtypeRemoteControlEndSeekingBackward:
NSLog(@"End seek backward...");
break;
default:
break;
}
[self changeUIState];
}
}
#pragma mark 界面布局
- (void)initLayout{
//专辑封面
UIImage *image = [UIImage imageNamed:@"wxl.jpg"];
CGRect *frame = [UIScreen mainScreen].applicationFrame;
UIImageView *imageView = [[UIImageView alloc] initWithFrame:frame];
imageView.image = image;
imageView.contentMode = UIViewContentModeScaleAspectFill;
[self.view addSubview:imageView];
//播放控制面板
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(, , , )];
view.backgroundColor = [UIColor lightGrayColor];
view.alpha = 0.9;
[self.view addSubview:view];
//添加播放按钮
_playButton = [UIButton buttonWithType:UIButtonTypeCustom];
_playButton.bounds = CGRectMake(, , , );
CGFloat playBtnX = view.frame.size.width/;
CGFloat playBtnY = view.frame.size.height/;
_playButton.center = CGPointMake(playBtnX, playBtnY);
[self changeUIState];
[_playButton addTarget:self
action:@selector(btnClick:)
forControlEvents:UIControlEventTouchUpInside];
[view addSubview:_playButton];
}
#pragma mark 界面状态
- (void)changeUIState{
if(_isPlaying){
UIImage *pauseImage = [UIImage imageNamed:@"playing_btn_pause_n.png"];
UIImage *pauseImageH = [UIImage imageNamed:@"playing_btn_pause_h.png"];
[_playButton setImage:pauseImage forState:UIControlStateNormal];
[_playButton setImage:pauseImageH forState:UIControlStateHighlighted];
}else{
UIImage *playImage = [UIImage imageNamed:@"playing_btn_play_n.png"];
UIImage *playImageH = [UIImage imageNamed:@"playing_btn_play_h.png"];
[_playButton setImage:playImage forState:UIControlStateNormal];
[_playButton setImage:playImageH forState:UIControlStateHighlighted];
}
}
- (void)btnClick:(UIButton *)btn{
if (_isPlaying) {
[_player pause];
}else{
[_player play];
}
_isPlaying =! _isPlaying;
[self changeUIState];
}
@end
二：首先查看一下关于UITouch的定义
//触摸事件在屏幕上有一个周期
typedef NS_ENUM(NSInteger, UITouchPhase) {
UITouchPhaseBegan, //开始触摸
UITouchPhaseMoved, //移动
UITouchPhaseStationary, //停留
UITouchPhaseEnded, //触摸结束
UITouchPhaseCancelled, //触摸中断
}; //检测是否支持3DTouch
typedef NS_ENUM(NSInteger, UIForceTouchCapability) {
UIForceTouchCapabilityUnknown = , //3D Touch检测失败
UIForceTouchCapabilityUnavailable = , //3D Touch不可用
UIForceTouchCapabilityAvailable = //3D Touch可用
}; NS_CLASS_AVAILABLE_IOS(2_0) @interface UITouch : NSObject //触摸产生或变化的时间戳 只读
@property(nonatomic,readonly) NSTimeInterval timestamp;
//触摸周期内的各个状态
@property(nonatomic,readonly) UITouchPhase phase;
//短时间内点击的次数 只读
@property(nonatomic,readonly) NSUInteger tapCount; //获取手指与屏幕的接触半径 IOS8以后可用 只读
@property(nonatomic,readonly) CGFloat majorRadius NS_AVAILABLE_IOS(8_0);
//获取手指与屏幕的接触半径的误差 IOS8以后可用 只读
@property(nonatomic,readonly) CGFloat majorRadiusTolerance NS_AVAILABLE_IOS(8_0); //触摸时所在的窗口 只读
@property(nullable,nonatomic,readonly,strong) UIWindow *window;
//触摸时所在视图
@property(nullable,nonatomic,readonly,strong) UIView *view;
//获取触摸手势
@property(nullable,nonatomic,readonly,copy) NSArray <UIGestureRecognizer *> *gestureRecognizers NS_AVAILABLE_IOS(3_2); //取得在指定视图的位置
// 返回值表示触摸在view上的位置
// 这里返回的位置是针对view的坐标系的（以view的左上角为原点(0,0)）
// 调用时传入的view参数为nil的话，返回的是触摸点在UIWindow的位置
- (CGPoint)locationInView:(nullable UIView *)view;
//该方法记录了前一个触摸点的位置
- (CGPoint)previousLocationInView:(nullable UIView *)view; //获取触摸压力值，一般的压力感应值为1.0 IOS9 只读
@property(nonatomic,readonly) CGFloat force NS_AVAILABLE_IOS(9_0); //获取最大触摸压力值
@property(nonatomic,readonly) CGFloat maximumPossibleForce NS_AVAILABLE_IOS(9_0); @end
知识点1：触摸时，图片移动（实例）
- (void)viewDidLoad
{
UIImageView *image = [[UIImageView alloc] initWithFrame:CGRectMake(20.0, 50.0, 45.0, 45.0)];
image.image = [UIImage imageNamed:@"baby.png"];
image.tag = ;
[self.view addSubview:image]; [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
} -(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
UIImageView *view1 = (UIImageView*)[self.view viewWithTag:];
CGPoint point = [touch locationInView:self.view];
CGRect frame = view1.frame;
frame.origin = point;
view1.frame = frame;
}
知识点2：创建可以拖动的视图
CGPoint originalLocation;
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
originalLocation = [touch locationInView:self.view];
} -(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint currentLocation = [touch locationInView:self.view];
CGRect frame = self.view.frame;
frame.origin.x += currentLocation.x-originalLocation.x;
frame.origin.y += currentLocation.y-originalLocation.y;
self.view.frame = frame;
}
这里先在touchesBegan中通过[touch locationInView:self.view]获取手指触摸在当前视图上的位置，用CGPoint变量记录，然后在手指移动事件touchesMoved方法中获取触摸对象当前位置，并通过于与原始位置的差值计算出移动偏移量，再设置当前视图的位置。
