iOS開發中的幾個手勢操作實例分享

2020-07-26 03:33:57

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手勢操作---識別單擊還是雙擊
在視圖上同時識別單擊手勢和雙擊手勢的問題在于，當檢測到一個單擊操作時，無法確定是確實是一個單擊操作或者只是雙擊操作中的第一次點擊。解決這個問題的方法就是:在檢測到單擊時，需要等一段時間等待第二次點擊，如果沒有第二次點擊，則為單擊操作；如果有第二次點擊，則為雙擊操作。
檢測手勢有兩種方法，一種是定制子視圖，重寫視圖從UIResponder類中繼承來的事件處理方法,即touchesBegan:withEvent:等一系列方法來檢測手勢；另一個方法是使用手勢識別器，即UIGestureRecognizer的各種具體子類。
一.重寫事件處理方法

復制代碼代碼如下:

- (id)init {
    if ((self = [super init])) {
        self.userInteractionEnabled = YES;
        self.multipleTouchEnabled = YES;
        // ...
    }
    return self;
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    UITouch *touch = [touches anyObject];
    CGPoint touchPoint = [touch locationInView:self];

    if (touch.tapCount == 1) {
        [self performSelector:@selector(handleSingleTap:) withObject:[NSValue valueWithCGPoint:touchPoint] afterDelay:0.3];
    }else if(touch.tapCount == 2)
    {
        [self handleDoubleTap:[NSValue valueWithCGPoint:touchPoint]];
    }
}

-(void)handleSingleTap:(NSValue*)pointValue
{
    CGPoint touchPoint = [pointValue CGPointValue];
    //...
}

-(void)handleDoubleTap:(NSValue*)pointValue
{
    CGPoint touchPoint = [pointValue CGPointValue];
    //...
}

首先確認定制視圖的userInteractionEnabled和multipleTouchEnabled屬性都為YES.
在touchesEnded:withEvent:方法中，如果是第一次觸摸結束，則cancelPreviousPerformRequestsWithTarget:方法不會起作用，因為self未調度任何方法，此時tapCount為1，使用performSelector:withObject:afterDelay:調用單擊事件處理方法，在0.3s鐘后執行。

復制代碼代碼如下:

[self performSelector:@selector(handleSingleTap:) withObject:[NSValue valueWithCGPoint:touchPoint] afterDelay:0.3];

如果這是一個單擊操作，則后面0.3鐘內不會再有觸摸事件，則handleSingleTap:方法執行，這樣識別出了單擊操作。
如果這是一個雙擊操作，則第二次點擊在0.3s內觸發，在第二次觸摸操作的touchesEnded:withEvent:方法中，cancelPreviousPerformRequestsWithTarget:首先會取消之前對handleSingleTap:方法的調度，使之不會執行，然后在調用handleDoubleTap:方法處理雙擊操作。
二.使用Gesture Recognizer
使用Gesture Recognizer識別就會簡單許多，只需添加兩個手勢識別器，分別檢測單擊和雙擊事件，設置必要的屬性即可。

復制代碼代碼如下:

- (id)init {
    if ((self = [super init])) {
    self.userInteractionEnabled = YES;
        UITapGestureRecognizer *singleTapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleSingleTap:)];
        singleTapGesture.numberOfTapsRequired = 1;
        singleTapGesture.numberOfTouchesRequired = 1;
        [self addGestureRecognizer:singleTapGesture];

        UITapGestureRecognizer *doubleTapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleDoubleTap:)];
        doubleTapGesture.numberOfTapsRequired = 2;
        doubleTapGesture.numberOfTouchesRequired = 1;
        [self addGestureRecognizer:doubleTapGesture];

        [singleTapGesture requireGestureRecognizerToFail:doubleTapGesture];
    }
    return self;
}
-(void)handleSingleTap:(UIGestureRecognizer *)sender{
    CGPoint touchPoint = [sender locationInView:self];
    //...
}
-(void)handleDoubleTap:(UIGestureRecognizer *)sender{
    CGPoint touchPoint = [sender locationInView:self];
    //...
}

唯一需要注意的是

復制代碼代碼如下:

[singleTapGesture requireGestureRecognizerToFail:doubleTapGesture];

這句話的意思時，只有當doubleTapGesture識別失敗的時候(即識別出這不是雙擊操作)，singleTapGesture才能開始識別，同我們一開始講的是同一個問題。

UIGestureRecognizer小應用
1、輕拍手勢：雙指、單擊，修改imageView的frame為(0,0,320,200)
2、長按手指：單指，修改imageView的alpha=0.5
3、實現平移、旋轉、捏合
4、輕掃：豎向輕掃實現圖：像隨機切換顯示；橫向輕掃實現：圖像消失，隨機修改imageview的背景顏色
5、imageview每次只能添加一種手勢識別器。

復制代碼代碼如下:

#define _originalRect CGRectMake(10, 50, 300, 450)  
#define _originalImageName  @"h4.jpeg"  
  
#import "HMTRootViewController.h"  
  
@interface HMTRootViewController (){  
  
    UITapGestureRecognizer       * _tapGesture;  
    UILongPressGestureRecognizer * _longGesture;  
    UIPanGestureRecognizer       * _panGesture;  
    UIRotationGestureRecognizer  * _rotateGesture;  
    UIPinchGestureRecognizer     * _pinchGesture;  
    UISwipeGestureRecognizer     * _verticalSwipeGesture;  
    UISwipeGestureRecognizer     * _horizontanlSwipeGesture;  
    BOOL isTopDownOfRightLeft;    // 垂直滑動是YES,水平滑動是NO  
      
}  
  
@property (nonatomic,retain) UIButton * button;  
@property (nonatomic,retain) UIImageView * imageView;  
  
@end  
  
@implementation HMTRootViewController  
  
- (void)dealloc{  
      
    RELEASE_SAFELY(_imageView);  
    RELEASE_SAFELY(_button);  
    [super dealloc];  
  
}  
  
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil  
{  
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];  
    if (self) {  
        // Custom initialization  
        isTopDownOfRightLeft = YES;  
    }  
    return self;  
}  
  
- (void)viewDidLoad  
{  
    [super viewDidLoad];  
    // Do any additional setup after loading the view.  
      
    [self createButtonView];  
    [self createImageView];  
  
}  
  
#pragma mark - 設置圖像  
- (void)createImageView{  
      
    self.imageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:_originalImageName]];  
    _imageView.frame = CGRectMake(10, 50, 300, 450);  
    _imageView.userInteractionEnabled = YES;  
    [self.view addSubview:_imageView];  
    [_imageView release];  
}  
  
  
  
#pragma mark - 設置手勢  
  
#pragma mark  點擊手勢  
- (void)createTapGestureRecognizer{  
     
  
    _tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(TapGestureRecognizer:)];  
    _tapGesture.numberOfTapsRequired = 1;  
    _tapGesture.numberOfTouchesRequired = 2;  
    [self.imageView addGestureRecognizer:_tapGesture];  
    [_tapGesture release];  
  
}  
  
- (void)TapGestureRecognizer:(UITapGestureRecognizer *)tapGesture{  
  
    self.imageView.frame = CGRectMake(0, 0, 320, 200);  
    NSLog(@"%@",NSStringFromCGRect(self.imageView.frame));  
  
}  
  
#pragma mark  長按手勢  
- (void)createLongGestureRecognizer{  
      
    _longGesture = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longGestureRecognizer:)];  
    _longGesture.numberOfTouchesRequired = 1;  
    _longGesture.minimumPressDuration = 1.0;  
    [self.imageView addGestureRecognizer:_longGesture];  
    [_longGesture release];  
      
}  
  
- (void)longGestureRecognizer:(UILongPressGestureRecognizer *)longGesture{  
  
    self.imageView.alpha = 0.5;  
    NSLog(@"%s",__FUNCTION__);  
  
}  
  
#pragma mark 平移拖拽手勢  
- (void)createPanGestureRecognizer{  
      
    _panGesture = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGestureRecognizer:)];  
    [self.imageView addGestureRecognizer:_panGesture];  
    [_panGesture release];  
      
}  
  
- (void)panGestureRecognizer:(UIPanGestureRecognizer *)panGesture{  
      
    NSLog(@"%s",__FUNCTION__);  
   
    CGPoint txty = [panGesture translationInView:self.view];  
    self.imageView.transform = CGAffineTransformTranslate(self.imageView.transform, txty.x, txty.y);  
      
    [panGesture setTranslation:CGPointMake(0, 0) inView:self.view];  
      
}  
  
#pragma mark 旋轉手勢  
- (void)createRotationGestureRecognizer{  
      
      
    _rotateGesture = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotationGestureRecognizer:)];  
    [self.imageView addGestureRecognizer:_rotateGesture];  
    [_rotateGesture release];  
      
}  
  
- (void)rotationGestureRecognizer:(UIRotationGestureRecognizer *)rotateGesture{  
      
    NSLog(@"%s",__FUNCTION__);  
    self.imageView.transform = CGAffineTransformRotate(self.imageView.transform, rotateGesture.rotation);  
    rotateGesture.rotation = 0;  
      
}  
  
#pragma mark 捏合縮放手勢  
- (void)createPinchGestureRecognizer{  
      
    _pinchGesture = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(pinchGestureRecognizer:)];  
    [self.imageView addGestureRecognizer:_pinchGesture];  
    [_pinchGesture release];  
      
}  
  
- (void)pinchGestureRecognizer:(UIPinchGestureRecognizer *)pinchGesture{  
      
    NSLog(@"%s",__FUNCTION__);  
    self.imageView.transform = CGAffineTransformScale(self.imageView.transform, pinchGesture.scale, pinchGesture.scale);  
    pinchGesture.scale = 1;  
      
}  
  
#pragma mark - 輕掃手勢  
#pragma mark 上下 豎 垂直輕掃  
- (void)createVerticalSwipeGestureRecognizer{  
     
    _verticalSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeGestureRecognizer:)];  
    _verticalSwipeGesture.direction = UISwipeGestureRecognizerDirectionUp | UISwipeGestureRecognizerDirectionDown;  
    [self.imageView addGestureRecognizer:_verticalSwipeGesture];  
    [_verticalSwipeGesture release];  
}  
  
#pragma mark 水平 左右輕掃  
- (void)createHorizontanlSwipeGesture{  
      
    _horizontanlSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeGestureRecognizer:)];  
    _horizontanlSwipeGesture.direction = UISwipeGestureRecognizerDirectionLeft |UISwipeGestureRecognizerDirectionRight;  
    [self.imageView addGestureRecognizer:_horizontanlSwipeGesture];  
      
}  
  
- (void)swipeGestureRecognizer:(UISwipeGestureRecognizer *)swipeGesture{  
      
    NSLog(@"%s",__FUNCTION__);  
     
    if (swipeGesture.direction == (UISwipeGestureRecognizerDirectionUp|UISwipeGestureRecognizerDirectionDown)) {  
        self.imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"h%i.jpeg",arc4random()%7+1]];  
        ;  
  
    }else if (swipeGesture.direction == (UISwipeGestureRecognizerDirectionLeft|UISwipeGestureRecognizerDirectionRight)){  
      
        self.imageView.image = nil;  
        self.imageView.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1.0];  
    }  
}  
  
  
#pragma mark - 設置按鈕  
- (void)createButtonView{  
      
    NSArray * buttonArray = @[@"輕點",@"長按",@"平移",@"旋轉",@"捏合",@"輕掃"];  
      
    for (int i = 0; i < [buttonArray count]; i++) {  
          
        self.button = [UIButton buttonWithType:UIButtonTypeSystem];  
        _button.frame = CGRectMake(10+50*i, 500, 50, 48);  
        [_button setTitle:[buttonArray objectAtIndex:i] forState:UIControlStateNormal];  
        [_button addTarget:self action:@selector(onClikButton:) forControlEvents:UIControlEventTouchUpInside];  
        _button.tag = i;  
        [self.view addSubview:_button];  
    }  
    
}  
  
- (void)onClikButton:(UIButton *)button{  
      
    [self resetImageView];  
    switch (button.tag) {  
        case 0:  
    
            [self createTapGestureRecognizer];  
            break;  
        case 1:  
   
            [self createLongGestureRecognizer];  
            break;  
        case 2:  
          
            [self createPanGestureRecognizer];  
            break;  
        case 3:  
             
            [self createRotationGestureRecognizer];  
            break;  
        case 4:  
              
            [self createPinchGestureRecognizer];  
            break;  
        case 5:  
            if (isTopDownOfRightLeft == YES) {  
                [self createVerticalSwipeGestureRecognizer];  
                isTopDownOfRightLeft = NO;  
            } else {  
                [self createHorizontanlSwipeGesture];  
                isTopDownOfRightLeft = YES;  
            }  
            break;  
        default:  
            break;  
    }  
      
}  
  
#pragma mark - 重置imageView  
- (void)resetImageView  
{  
    for (int i = 0; i < [self.imageView.gestureRecognizers count]; i++) {  
        [self.imageView removeGestureRecognizer:[self.imageView.gestureRecognizers objectAtIndex:i]];  
    }  
    self.imageView.alpha = 1.0;  
    self.imageView.transform = CGAffineTransformIdentity;  
    self.imageView.frame = _originalRect;  
    self.imageView.image = [UIImage imageNamed:_originalImageName];  
}  
  
  
- (void)didReceiveMemoryWarning  
{  
    [super didReceiveMemoryWarning];  
    // Dispose of any resources that can be recreated.  
}  
  
@end  