Question

在我的代码中，我有一个对象数组，这些对象是带有UIImages的UIImageViews。

我在-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event中使用for循环来逐个移动数组中的所有对象。

一旦将它们移动到主视图上的不同位置，我希望能够抓住任何这些对象并将它们移动到其他位置。

我不确定如何做到最好。有没有办法可以使用touchesbegin，这样我只能拖动我点击的项目？

基本上，现在有五个UIImageViews，每个都有UIImage，我试图达到这样的程度，当我点击它们中的任何一个时，它们都可以移动。

Answer 1

编辑：John Muchow在博客here上发布了此消息。你应该能够适应自己的目的。

//UIDraggableImageView.h
#import <UIKit/UIKit.h>

@interface UIDraggableImageView : UIImageView
{
    CGPoint currentPoint;
}

@end

//UIDraggableImageView.m
#import "UIDraggableImageView.h"

@implementation UIDraggableImageView

- (id)initWithImage:(UIImage *)image
{
    if (self = [super initWithImage:image]) {
        self.userInteractionEnabled = YES;
    }
    return self;
}

-(void)dealloc {
    [super dealloc];
}

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
    // When a touch starts, get the current location in the view
    currentPoint = [[touches anyObject] locationInView:self];
}

- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
    // Get active location upon move
    CGPoint activePoint = [[touches anyObject] locationInView:self];

    // Determine new point based on where the touch is now located
    CGPoint newPoint = CGPointMake(self.center.x + (activePoint.x - currentPoint.x),
                                   self.center.y + (activePoint.y - currentPoint.y));

    //--------------------------------------------------------
    // Make sure we stay within the bounds of the parent view
    //--------------------------------------------------------
    float midPointX = CGRectGetMidX(self.bounds);
    // If too far right...
    if (newPoint.x > self.superview.bounds.size.width  - midPointX)
        newPoint.x = self.superview.bounds.size.width - midPointX;
    else if (newPoint.x < midPointX)  // If too far left...
        newPoint.x = midPointX;

    float midPointY = CGRectGetMidY(self.bounds);
    // If too far down...
    if (newPoint.y > self.superview.bounds.size.height  - midPointY)
        newPoint.y = self.superview.bounds.size.height - midPointY;
        else if (newPoint.y < midPointY)  // If too far up...
        newPoint.y = midPointY;

    // Set new center location
    self.center = newPoint;
}

@end

Answer 2

我在可拖动视图中使用UIPanGestureRecognizer取得了类似的成功。要连接它，它可能看起来像这样：

@implementation DraggableView

-(id)initWithFrame:(CGRect)frame
{
   ...
   ...
   UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)] autorelease];
   [self addGestureRecognizer:panGesture];
   ..
   return self;
}
@end

在pan:方法中，您可以检查手势的状态，甚至捕捉手势的位置并使用它来重新定位视图。这是一个粗略示例：

-(void)pan:(UIPanGestureRecognizer *)gesture
{

   if (gesture.state==UIGestureRecognizerStateChanged)
   {
      //We're moving!
      UIView *aRootView = <perhaps your root view controller's view>;
      CGPoint currentOrigin = [gesture translationInView:aRootView];
      self.frame = CGRectMake(currentOrigin.x,currentOrigin.y,self.frame.size.width,self.frame.size.hight);
      ...
      ...
   }

}

UIPanGestureRecognizer上的

Here is more reading。

Answer 3

您可能需要考虑为要移动的视图添加手势识别器，这样您就可以轻松判断它们何时被轻击，并且您可以使用touchesMoved来移动它们...

Answer 4

在按钮上单击将相机胶卷中的图像添加到imageview。图像可以放大和缩小，并应将该图像拖动到视图中的任何位置。

拖动特定的UIImageView

4 个答案: