在屏幕上拖動UIImageViews？

Question

我在我的應用程序中有以下代碼，每次我都可以複製和粘貼，但我寧願讓它在其他區域也可以重用。它允許我在屏幕上拖動UIImageView，但是我不喜歡這個錯誤很容易出錯的事實！

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { 
UITouch *touch = [touches anyObject]; 
CGPoint location = [touch locationInView:self.view]; 




if (touch.view == first) { 
    first.center = location; 

    if (((first.center.x >= 100) && (first.center.y >= 100) && 
     (first.center.x <= 150) && (first.center.y <= 150))) { 

     first.center = CGPointMake(125, 125); 
     [first setUserInteractionEnabled:NO]; 

     theCentre = [[NSUserDefaults standardUserDefaults] init]; 

     NSString *centre = NSStringFromCGPoint(first.center); 

     [theCentre setObject:centre forKey:@"centre"]; 

     // NSLog(@"%@", [theCentre objectForKey:@"centre"]); 
     [theCentre synchronize]; 

    } 

} 
if (touch.view == second) { 
    second.center = location; 

    if (((second.center.x >= 150) && (second.center.y >= 150) && 
     (second.center.x <= 180) && (second.center.y <= 180))) { 

     second.center = CGPointMake(165, 165); 
     [second setUserInteractionEnabled:NO]; 

     theCentre = [[NSUserDefaults standardUserDefaults] init]; 

     NSString *centre = NSStringFromCGPoint(second.center); 

     [theCentre setObject:centre forKey:@"secondCentre"]; 

     // NSLog(@"%@", [theCentre objectForKey:@"centre"]); 
     [theCentre synchronize]; 
} 
} 
if (touch.view == third) { 
    third.center = location; 

    if (((third.center.x >= 200) && (third.center.y >= 200) && 
     (third.center.x <= 230) && (third.center.y <= 230))) { 

     third.center = CGPointMake(215, 215); 
     [third setUserInteractionEnabled:NO]; 

     theCentre = [[NSUserDefaults standardUserDefaults] init]; 

     NSString *centre = NSStringFromCGPoint(third.center); 

     [theCentre setObject:centre forKey:@"thirdCentre"]; 

     // NSLog(@"%@", [theCentre objectForKey:@"centre"]); 
     [theCentre synchronize]; 
    } 

} 

} 

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 
[self touchesBegan:touches withEvent:event]; 
} 

我已經嘗試過快速枚舉，但這使得一個imageView移動，其他人只是消失在屏幕上！顯然不是想要的效果...

Answer 1

我推薦使用UIGestureRecognizers。當您設置你的形象的看法寫：

NSArray *imageViews = [NSArray arrayWithObjects:first, second, third, nil]; 
for (UIView *imageView in imageViews) { 
    UIPanGestureRecognizer *panGR = [[UIPanGestureRecognizer alloc]  
     initWithTarget:self action:@selector(handlePanGesture:)] 
    [imageView addGestureRecognizer:panGR]; 
    [panGR release]; 
} 

，然後實現手勢處理機：

- (void)handlePanGesture:(UIGestureRecognizer *)gestureRecognizer { 
    UIPanGestureRecognizer *panGR = (UIPanGestureRecognizer *)gestureRecognizer; 
    UIView *gestureView = [panGR view]; 
    CGPoint translation = [panGR translationInView:gestureView]; 
    gestureView.center = CGPointMake(gestureView.center.x + translation.x, 
            gestureView.center.y + translation.y); 
    [panGR setTranslation:CGPointZero inView:gestureView]; 
} 

此代碼是未經測試（用記事本），但是這是正確的方向。