iOS开发UIEvent事件简介

1、UIEvent简介

　　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分为四类: UIEventType

typedef NS_ENUM(NSInteger, UIEventType) {
    UIEventTypeTouches,//触摸事件类型 iOS3.0之后可以用
    UIEventTypeMotion,//摇晃事件类型 iOS3.0之后可以用
    UIEventTypeRemoteControl,//遥控事件类型 iOS4.0之后可以用
    UIEventTypePresses NS_ENUM_AVAILABLE_IOS(9_0),//物理按钮事件类型 iOS9.0之后可以用
};

　　子事件类型：UIEventSubtype

typedef NS_ENUM(NSInteger, UIEventSubtype) {
    //事件没有子类型 iOS3.0之后可以用
    UIEventSubtypeNone                              = ,

    //事件子类型晃动的设备 iOS3.0之后可以用
    UIEventSubtypeMotionShake                       = ,

    //遥控的事件子类型 iOS4.0之后可以用
    UIEventSubtypeRemoteControlPlay                 = ,//播放
    UIEventSubtypeRemoteControlPause                = ,//暂停
    UIEventSubtypeRemoteControlStop                 = ,//停止
    UIEventSubtypeRemoteControlTogglePlayPause      = ,//播放和暂停之间切换【操作：播放或暂停状态下，按耳机线控中间按钮一下】
    UIEventSubtypeRemoteControlNextTrack            = ,//下一曲【操作：按耳机线控中间按钮两下】
    UIEventSubtypeRemoteControlPreviousTrack        = ,//上一曲【操作：按耳机线控中间按钮三下】
    UIEventSubtypeRemoteControlBeginSeekingBackward = ,//快退开始【操作：按耳机线控中间按钮三下不要松开】
    UIEventSubtypeRemoteControlEndSeekingBackward   = ,//快退结束【操作：按耳机线控中间按钮三下到了快退的位置松开】
    UIEventSubtypeRemoteControlBeginSeekingForward  = ,//快进开始【操作：按耳机线控中间按钮两下不要松开】
    UIEventSubtypeRemoteControlEndSeekingForward    = ,//快进结束【操作：按耳机线控中间按钮两下到了快进的位置松开】
};

2、相关API

NS_CLASS_AVAILABLE_IOS(2_0) @interface UIEvent : NSObject

@property(nonatomic,readonly) UIEventType     type NS_AVAILABLE_IOS(3_0);//事件类型
@property(nonatomic,readonly) UIEventSubtype  subtype NS_AVAILABLE_IOS(3_0);//子事件类型

@property(nonatomic,readonly) NSTimeInterval  timestamp;//事件发生时间

//返回与接收器相关联的所有触摸对象。
#if UIKIT_DEFINE_AS_PROPERTIES
@property(nonatomic, readonly, nullable) NSSet <UITouch *> *allTouches;
#else
- (nullable NSSet <UITouch *> *)allTouches;
#endif
- (nullable NSSet <UITouch *> *)touchesForWindow:(UIWindow *)window;//返回属于一个给定视图的触摸对象，用于表示由接收器所表示的事件。
- (nullable NSSet <UITouch *> *)touchesForView:(UIView *)view;//返回属于一个给定窗口的接收器的事件响应的触摸对象。
- (nullable NSSet <UITouch *> *)touchesForGestureRecognizer:(UIGestureRecognizer *)gesture NS_AVAILABLE_IOS(3_2);//返回触摸对象被传递到特殊手势识别

//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

3、触摸事件示例

　　相关方法：

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
- (void)touchesEstimatedPropertiesUpdated:(NSSet<UITouch *> *)touches NS_AVAILABLE_IOS(9_1);

　　拖动和移动效果图：

　　代码展示：

//拖动视图
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    CGPoint currPoint = [touch locationInView:self.view];
    CGPoint prePoint = [touch previousLocationInView:self.view];
    CGRect frame = self.btnView.frame;
    frame.origin.x += currPoint.x -prePoint.x;
    frame.origin.y += currPoint.y -prePoint.y;
    self.btnView.frame = frame;
}

//点击移动
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [touches anyObject];
    CGRect frame = self.btnView.frame;
    frame.origin = [touch locationInView:self.view];
    self.btnView.frame = frame;
}

4、摇晃事件示例

　　相关方法：

- (void)motionBegan:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0);
- (void)motionEnded:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0);
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(3_0);

　　效果图：模拟器摇一摇「Hardware」-「Shake Gesture」来测试 ，快捷键：command+control+z

　　摇一摇显示随机图片：

@implementation MotionImageView
- (instancetype)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        self.image = [self getImage];
    }
    return self;
}

- (BOOL)canBecomeFirstResponder{
    return YES;
}

- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event{
    if (motion == UIEventSubtypeMotionShake) {
        self.image = [self getImage];
    }
}
- (UIImage *)getImage{
    int index = arc4random() % +;
    NSString *imageName = [NSString stringWithFormat:@"pic%i.png",index];
    UIImage *image = [UIImage imageNamed:imageName];
    return image;

}
@end

　　在ViewController中使用：

//成为第一响应者
- (void)viewDidAppear:(BOOL)animated{
    [self.imageView becomeFirstResponder];
}
//注销第一响应者
- (void)viewDidDisappear:(BOOL)animated{
    [self.imageView resignFirstResponder];
}
//支持摇一摇功能
- (void)viewDidLoad {
    [super viewDidLoad];
    [UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;
}

5、遥控事件示例

　　相关方法：

- (void)remoteControlReceivedWithEvent:(nullable UIEvent *)event NS_AVAILABLE_IOS(4_0);

　　代码实现：

#import "VideoViewController.h"
#import <AVFoundation/AVFoundation.h>
@interface VideoViewController ()
{
    UIButton *_playButton;
    BOOL _isPlaying;
    AVPlayer    *_player;
}
@end

@implementation VideoViewController

- (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://music.163.com/song/media/outer/url?id=1293886117.mp3"];
    _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;
                NSLog(@"播放");
                break;
            case UIEventSubtypeRemoteControlTogglePlayPause:
                [self btnClick:_playButton];
                NSLog(@"播放和暂停之间切换【操作：播放或暂停状态下，按耳机线控中间按钮一下】");
                break;
            case UIEventSubtypeRemoteControlNextTrack:
                NSLog(@"下一曲【操作：按耳机线控中间按钮两下】");
                break;
            case UIEventSubtypeRemoteControlPreviousTrack:
                NSLog(@"上一曲【操作：按耳机线控中间按钮三下】");
                break;
            case UIEventSubtypeRemoteControlBeginSeekingForward:
                NSLog(@"快进开始【操作：按耳机线控中间按钮两下不要松开】");
                break;
            case UIEventSubtypeRemoteControlEndSeekingForward:
                NSLog(@"快进结束【操作：按耳机线控中间按钮两下到了快进的位置松开】");
                break;
            case UIEventSubtypeRemoteControlBeginSeekingBackward:
                NSLog(@"快退开始【操作：按耳机线控中间按钮三下不要松开】");
                break;
            case UIEventSubtypeRemoteControlEndSeekingBackward:
                NSLog(@"快退结束【操作：按耳机线控中间按钮三下到了快退的位置松开】");
                break;
            case UIEventSubtypeRemoteControlStop:
                NSLog(@"停止");
                break;
            case UIEventSubtypeRemoteControlPause:
                NSLog(@"暂停");
                break;
            default:
                break;
        }
        [self changeUIState];
    }

}

#pragma mark 界面布局
- (void)initLayout{
    //专辑封面
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:[UIScreen mainScreen].bounds];
    imageView.image = [UIImage imageNamed:@"pic1.jpg"];
    imageView.contentMode = UIViewContentModeScaleAspectFill;
    [self.view addSubview:imageView];

    //播放控制面板
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(, , [UIScreen mainScreen].bounds.size.width, )];
    view.backgroundColor = [UIColor yellowColor];
    view.alpha = 0.9;
    [self.view addSubview:view];

    //添加播放按钮
    _playButton = [UIButton buttonWithType:UIButtonTypeCustom];
    _playButton.bounds = CGRectMake(, , , );
    _playButton.center = CGPointMake(CGRectGetWidth(view.frame)/,CGRectGetHeight(view.frame)/);
    [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:@"pic2.png"];
        [_playButton setImage:pauseImage forState:UIControlStateNormal];
    }else{
        UIImage *playImage = [UIImage imageNamed:@"pic3.png"];
        [_playButton setImage:playImage forState:UIControlStateNormal];
    }
}

- (void)btnClick:(UIButton *)btn{
    if (_isPlaying) {
        [_player pause];
    }else{
        [_player play];
    }
    _isPlaying =! _isPlaying;
    [self changeUIState];
}
@end

线控代码实现

　　号外1：获取网易云mp3路径

　　号外2：后台播放音乐

- (void)applicationWillResignActive:(UIApplication *)application {
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    AVAudioSession *session = [AVAudioSession sharedInstance];
    [session setActive:YES error:nil];
    [session setCategory:AVAudioSessionCategoryPlayback error:nil];
}

6、物理按钮示例

　　按压事件代表了对一个游戏控制器,苹果TV远程,或其他有物理按钮的设备之间的交互。；

　　所以对于iPhone的手机而言在没有物理按键连接的情况下,是无法触发该事件的；

　　相关方法：

//物理按钮 深按API，一般用于遥控器
- (void)pressesBegan:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);// 开始按压的时候调用
- (void)pressesChanged:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);// 按压改变的时候调用
- (void)pressesEnded:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);// 按压结束的时候调用
- (void)pressesCancelled:(NSSet<UIPress *> *)presses withEvent:(nullable UIPressesEvent *)event NS_AVAILABLE_IOS(9_0);// 当系统发出取消按压事件的时候调用

　　UIPress相关API

NS_ENUM_AVAILABLE_IOS(9_0) typedef NS_ENUM(NSInteger, UIPressPhase) {
    UIPressPhaseBegan,         // 开始
    UIPressPhaseChanged,       // 变化
    UIPressPhaseStationary,    // 按下不动时
    UIPressPhaseEnded,         // 结束
    UIPressPhaseCancelled,     // 取消
};

NS_ENUM_AVAILABLE_IOS(9_0) typedef NS_ENUM(NSInteger, UIPressType) {
    UIPressTypeUpArrow,     //向上的键被按压
    UIPressTypeDownArrow,   //向下的键被按压
    UIPressTypeLeftArrow,   //向左的键被按压
    UIPressTypeRightArrow,  //向右的键被按压

    UIPressTypeSelect,      //选择 的键被按压
    UIPressTypeMenu,        //菜单 的键被按压
    UIPressTypePlayPause,   //播放/暂停 的键被按压
};

NS_CLASS_AVAILABLE_IOS(9_0) @interface UIPress : NSObject

@property(nonatomic,readonly) NSTimeInterval   timestamp;   //时间
@property(nonatomic,readonly) UIPressPhase     phase;       //按下阶段
@property(nonatomic,readonly) UIPressType      type;        //按下的类型

@property(nullable,nonatomic,readonly,strong) UIWindow                        *window; //所处视图
@property(nullable,nonatomic,readonly,strong) UIResponder                     *responder;//
@property(nullable,nonatomic,readonly,copy)   NSArray <UIGestureRecognizer *> *gestureRecognizers;//手势

@property(nonatomic, readonly) CGFloat force; //按钮按压的力 返回一个介于0和1之间的值。数字按钮返回0或1。