我已经按照这篇非常有用的教程添加了类似tinder的滑动效果(http://guti.in/articles/creating-tinder-like-animations/),然而我有一个问题——当图片消失时,我想用另一张图片来替换它。我该在哪里做这个操作?
请查看这个使用Swift 4编写的项目:
https://github.com/nickypatson/TinderSwipeView
以下是处理拖动手势的函数:
func beingDragged(_ gestureRecognizer: UIPanGestureRecognizer) {
xFromCenter = gestureRecognizer.translation(in: self).x
yFromCenter = gestureRecognizer.translation(in: self).y
switch gestureRecognizer.state {
//%%% just started swiping
case .began:
originalPoint = self.center;
break;
//%%% in the middle of a swipe
case .changed:
let rotationStrength = min(xFromCenter / ROTATION_STRENGTH, ROTATION_MAX)
let rotationAngel = .pi/8 * rotationStrength
let scale = max(1 - fabs(rotationStrength) / SCALE_STRENGTH, SCALE_MAX)
center = CGPoint(x: originalPoint.x + xFromCenter, y: originalPoint.y + yFromCenter)
let transforms = CGAffineTransform(rotationAngle: rotationAngel)
let scaleTransform: CGAffineTransform = transforms.scaledBy(x: scale, y: scale)
self.transform = scaleTransform
updateOverlay(xFromCenter)
break;
case .ended:
afterSwipeAction()
break;
case .possible:break
case .cancelled:break
case .failed:break
}
}
让我们尝试一下这个方法。首先,我们需要创建一个UIPanGestureRecognizer对象,并将其指向self和beingDragged方法。然后,将其添加到手势识别器中。
希望这能起作用。请告诉我。
谢谢。
这个答案基于cwRichardKim的代码/回复(感谢cwRichardKim!)。我没有找到如何在每张卡片上添加图片的指南。下面是我的方法(在此示例中,图像URL硬编码,但在实际应用程序中可以从云获取图像URL):
在DraggableView.h中:
@property (nonatomic,strong)UIImageView* photoImageView; //%%% a placeholder for member photo to place on card
在DraggableView.m文件中:
...
@synthesize photoImageView;
...
// - (id)initWithFrame:(CGRect)frame ...
// add photo to card
//You need to specify the frame of the view
UIView *photoView = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.frame.size.width,self.frame.size.width)];
photoImageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"place_holder_image.png"]];
// UIImageView *imageView = [[UIImageView alloc] initWithImage:photo];
//specify the frame of the imageView in the superview , here it will fill the superview
photoImageView.frame = photoView.bounds;
// add the imageview to the superview
[photoView addSubview:photoImageView];
//add the view to the main view
[self addSubview:photoView];
@property(retain,nonatomic)NSArray* exampleCardUrls;
in DraggableViewBackground.m:
...
@synthesize exampleCardUrls;
...
exampleCardUrls = [[NSArray alloc]initWithObjects:@"http://images.clipartpanda.com/clipart-people-nTBX8zkgc.jpeg",@"http://epilepsyu.com/wp-content/uploads/2014/01/happy-people.jpg",@"http://alivecampus.com/wp-content/uploads/2014/09/people-02.jpg",@"https://www.google.com/images/srpr/logo11w.png",@"http://modalpoint.com/wp-content/uploads/2014/11/people-blue-stick-people-hi.png", nil];
...
// ... -(DraggableView *)createDraggableViewWithDataAtIndex:(NSInteger)index ...
// retrieve image for cell in background
NSURL *url = [NSURL URLWithString:exampleCardUrls[index]];
[self loadImage:url withIndex:index];
...
#pragma mark - cloud, load image
- (void)loadImage:(NSURL *)imageURL withIndex:(NSInteger)index
{
// create array of objects to pass to next method
NSMutableArray* params = [[NSMutableArray alloc]init];
[params addObject:imageURL];
NSNumber *indexNumber = [NSNumber numberWithInt:index];
[params addObject:indexNumber];
NSOperationQueue *queue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc]
initWithTarget:self
selector:@selector(requestRemoteImage:)
object:params];
[queue addOperation:operation];
}
- (void)requestRemoteImage:(NSMutableArray*)params
{
// get data from params
NSURL* imageURL = params[0];
NSData *imageData = [[NSData alloc] initWithContentsOfURL:imageURL];
UIImage *image = [[UIImage alloc] initWithData:imageData];
params[0] = image;
[self performSelectorOnMainThread:@selector(placeImageInUI:) withObject:params waitUntilDone:YES];
}
- (void)placeImageInUI:(NSArray*)params
{
// get data from params
UIImage* image = params[0];
NSNumber* indexNumber = params[1];
NSInteger index = [indexNumber integerValue];
DraggableView* myDraggableView = allCards[index];
myDraggableView.photoImageView.image = image;
allCards[index] = myDraggableView;
}