iOS的手勢控制

今天做了一下iOS的手勢控制

手勢自然就是在真機上面，除了點擊這種短暫動作之外的操作，主要包括：

1 Pan

Pan就是最常見的拖動了。單個手指從屏幕滑動，系統會識別出這是一個pan gesture，當然代碼裏面需要包含一些固有的定義，纔可以對這個手勢做反應。 

注：在xcode的模擬器上面，只需要按住鼠標（or觸摸板）不放，然後拖動，就是模仿真機中的pan了。

2 Rotation

當兩個手指同時觸摸在屏幕，然後做同旋轉方向的曲線拖動，就是Rotation 這個gesture

注：在xcode的模擬器上面，需要按住鍵盤的Option，同時按住鼠標（or觸摸板）並開始拖動，模擬器上會模擬出兩個小白圓，作爲rotation。

3 Pinch

當兩個手指同時觸摸在屏幕，然後做反向直線拖動，就是Pinch

注：在xcode的模擬器上面，需要按住鍵盤的Option，同時按住鼠標（or觸摸板）並開始拖動，模擬器上會模擬出兩個小白圓，作爲rotation。

前端時間做了一個剪切圖片的cropper，其中用到了手勢控制，直接整個.m分享出來，應該能看懂的。。

#import "HYCImageCropper.h"

@interface HYCImageCropper ()
{
    UIImageView *imageView;
}

//rotation gesture需要的中間變量，記錄上一個rotation參數
@property CGFloat lastRotation;

@end

@implementation HYCImageCropper

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
}
*/

-(id)initWithFrame:(CGRect)frame Image:(UIImage *)image Area:(CGRect)area
{
    self = [super initWithFrame:frame];
    self.backgroundColor = [UIColor whiteColor];
   
    //add image view and its image
    imageView = [[UIImageView alloc]initWithFrame:self.bounds];
    [imageView setImage:image];
    [self addSubview: imageView];
    [imageView setUserInteractionEnabled:YES];
   
    //add gestures on imageView
    UIRotationGestureRecognizer *rotateGes = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotateImage:)];
    rotateGes.delegate = self;
    [imageView addGestureRecognizer:rotateGes];
   
    UIPinchGestureRecognizer *scaleGes = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scaleImage:)];
    scaleGes.delegate = self;
    [imageView addGestureRecognizer:scaleGes];
   
    UIPanGestureRecognizer *moveGes = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(moveImage:)];
    moveGes.delegate = self;
    [imageView addGestureRecognizer:moveGes];

    return self;
}


- (void)moveImage:(UIPanGestureRecognizer *)sender
{
    NSLog(@"move!");
   
    //使目標view升到表層
    [self bringSubviewToFront:imageView];
    //求當前gesture在主view中的座標
    CGPoint location = [sender locationInView:self];
    //利用center屬性直接定義目標view位置
    sender.view.center = CGPointMake(location.x,  location.y);
   
}

- (void)scaleImage:(UIPinchGestureRecognizer *)sender
{
    NSLog(@"scale!");
   
    //使目標view升到表層
    [self bringSubviewToFront:sender.view];
    //求當前gesture在主view中的座標
    CGPoint location = [sender locationInView:self];
    sender.view.center = CGPointMake(location.x, location.y);
    //用core graph裏面封裝好的CGAffineTransformScale做scale變換
    sender.view.transform = CGAffineTransformScale(sender.view.transform, sender.scale, sender.scale);
    sender.scale = 1;

}

- (void)rotateImage:(UIRotationGestureRecognizer *)sender
{
    NSLog(@"rotate");
   
    //使目標view升到表層
    [self bringSubviewToFront:sender.view];
    //求當前gesture在主view中的座標
    CGPoint location = [sender locationInView:self];
    sender.view.center = CGPointMake(location.x, location.y);
    //如果沒有旋轉，就把lastRotate參數置爲0
    if ([sender state] == UIGestureRecognizerStateEnded) {
        self.lastRotation = 0;
        return;
    }
    //找到上一次的transform參數，以便接着旋轉
    CGAffineTransform currentTransform = imageView.transform;
    //求出新的旋轉參數，並使用CGAffineTransformRotate
    CGFloat rotation = 0.0 - (self.lastRotation - sender.rotation);
    CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform, rotation);
    imageView.transform = newTransform;
    //當rotate gesture停了，就記錄這時候的狀態到lastRotate這個變量，一邊下一次接着旋轉
    self.lastRotation = sender.rotation;
}

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return  YES;
}

@end