所以，我非常喜欢Android上的Google Now卡片界面。最近它甚至还来到了iOS。
是否有任何教程或示例项目可以帮助我为我的iOS应用程序创建卡片界面？
根据我的研究，我已经能够使用自定义UICollectionViewFlowLayout复制“堆叠”卡。
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
NSArray *allAttributesInRect = [super layoutAttributesForElementsInRect:rect];
CGPoint centerPoint = CGPointMake(CGRectGetMidX(self.collectionView.bounds), CGRectGetMidY(self.collectionView.bounds));
for (UICollectionViewLayoutAttributes *cellAttributes in allAttributesInRect)
{
if (CGRectContainsPoint(cellAttributes.frame, centerPoint))
{
cellAttributes.transform = CGAffineTransformIdentity;
cellAttributes.zIndex = 1.0;
}
else
{
cellAttributes.transform = CGAffineTransformMakeScale(0.75, 0.75);
}
}
return allAttributesInRect;
}
然后我将最小行间距设置为负值，使它们显示为“堆叠”。
滚动时，我希望卡片保持在底部，只有一辆汽车可以向上扩展并在屏幕中居中。然后我会将该卡从屏幕上滚动，堆栈中的下一张“卡片”将从堆栈向上滚动并在屏幕上居中。我猜这会动态调整最小行间距？
我认为没有任何教程或课程完全符合您的要求。但是，如果您不介意仅针对iOS6及更高版本，则可以使用UICollectionView。使用标准的垂直流布局，您应该很难做到您想要实现的目标。看一眼：
我知道这些例子看起来并不像你想要达到的那样。但是一旦你掌握了使用这些网站的UICollectionView的基本概念，你就能够立即构建卡片布局。
我创建了一个快速示例，展示了一种处理单元格“平移”的潜在方法。确保添加必要的代码以从//Insert code to delete the cell here的集合视图中删除该项目，然后它将填充通过删除单元格创建的间隙。
CLCollectionViewCell.h
#import <QuartzCore/QuartzCore.h>
#import <UIKit/UIKit.h>
@interface CLCollectionViewCell : UICollectionViewCell <UIGestureRecognizerDelegate>
@property (assign, setter = setDeleted:) BOOL isDeleted;
@property (strong) UIPanGestureRecognizer *panGestureRecognizer;
@end
CLCollectionViewCell.m
#import "CLCollectionViewCell.h"
@implementation CLCollectionViewCell
- (id)initWithCoder:(NSCoder *)aDecoder {
if (self = [super initWithCoder:aDecoder]) {
// Create a pan gesture recognizer with self set as the delegate and add it the cell
_panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureRecognizerDidChange:)];
[_panGestureRecognizer setDelegate:self];
[self addGestureRecognizer:_panGestureRecognizer];
// Don't clip to bounds since we want the content view to be visible outside the bounds of the cell
[self setClipsToBounds:NO];
// For debugging purposes only: set the color of the content view
[[self contentView] setBackgroundColor:[UIColor greenColor]];
}
return self;
}
- (void)panGestureRecognizerDidChange:(UIPanGestureRecognizer *)panGestureRecognizer {
if ([self isDeleted]) {
// The cell should be deleted, leave the state of the cell as it is
return;
}
// Percent holds a float value between -1 and 1 that indicates how much the user moved his finger relative to the width of the cell
CGFloat percent = [panGestureRecognizer translationInView:self].x / [self frame].size.width;
switch ([panGestureRecognizer state]) {
case UIGestureRecognizerStateChanged: {
// Create the 'throw animation' and base its current state on the percent
CGAffineTransform moveTransform = CGAffineTransformMakeTranslation(percent * [self frame].size.width, 0.f);
CGAffineTransform rotateTransform = CGAffineTransformMakeRotation(percent * M_PI / 20.f);
CGAffineTransform transform = CGAffineTransformConcat(moveTransform, rotateTransform) ;
// Apply the transformation to the content view
[[self contentView] setTransform:transform];
break;
}
case UIGestureRecognizerStateFailed:
case UIGestureRecognizerStateEnded:
case UIGestureRecognizerStateCancelled: {
// Delete the current cell if the absolute value of the percent is above O.7 or the absolute value of the velocity of the gesture is above 600
if (fabsf(percent) > 0.7f || fabsf([panGestureRecognizer velocityInView:self].x) > 600.f) {
// The direction is -1 if the gesture is going left and 1 if it's going right
CGFloat direction = percent < 0.f ? -1.f : 1.f;
// Multiply the direction to make sure the content view will be removed entirely from the screen
direction *= 1.5f;
// Create the transform based on the direction of the gesture
CGAffineTransform moveTransform = CGAffineTransformMakeTranslation(direction * [self frame].size.width , 0.f);
CGAffineTransform rotateTransform = CGAffineTransformMakeRotation(direction * M_PI / 20.f);
CGAffineTransform transform = CGAffineTransformConcat(moveTransform, rotateTransform);
// Calculate the duration of the animation based on the velocity of the pan gesture recognizer and normalize abnormal high and low values
CGFloat duration = fabsf(1000.f / [panGestureRecognizer velocityInView:self].x);
duration = duration > 2.f ? duration = 2.f : duration;
duration = duration < 0.2f ? duration = 0.2f : duration;
// Animate the 'throwing away' of the cell and update the collection view once it's completed
[UIView animateWithDuration:duration
animations:^(){
[[self contentView] setTransform:transform];
}
completion:^(BOOL finished){
[self setDeleted:YES];
// Insert code to delete the cell here
// e.g. [collectionView deleteItemsAtIndexPaths:@[[collectionView indexPathForCell:self]]];
}];
} else {
// The cell shouldn't be deleted: animate the content view back to its original position
[UIView animateWithDuration:1.f animations:^(){
[[self contentView] setTransform:CGAffineTransformIdentity];
}];
}
break;
}
default: {
break;
}
}
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
// Return YES to make sure the pan gesture recognizer doesn't interfere with the gesture recognizer of the collection view
return YES;
}
@end