UICollectionView自定义相册

2016-10-07 本文已影响501人 IIronMan

效果图

Untitled11卡片动画1.gif

一.我们要对UICollectionView的布局进行自定义

这是我自定义的宏以及静态变量

#define WIDTH  [UIScreen mainScreen].bounds.size.width
#define Height [UIScreen mainScreen].bounds.size.height
#define CWColor(a,b,c) [UIColor colorWithRed:(a)/255.0 green:(b)/255.0 blue:(c)/255.0 alpha:1.0]
/**
 *   static 表示只在此文件里可以访问(防止其他文件访问) const防止别人去改
 */
static NSString *const ID = @"cellID";

1.自定义布局,集成UICollectionViewFlowLayout即可

布局的设置(重点)
UICollectionViewFlowLayout 继承它就拥有流水的效果
UICollectionViewLayout 如果继承它,那么一切布局要从头开始
下面我们就重点讲讲自定义布局的里面一些知识点,我就以我布局的CWLineLayout为例

#import "CwLineLayout.h"
#define WIDTH  [UIScreen mainScreen].bounds.size.width
#define Height [UIScreen mainScreen].bounds.size.height

static const CGFloat CWItemH = 120;
@implementation CwLineLayout

-(instancetype)init
{
    self = [super init];

    if (self) {
  
  }
   return self;
}

/**
 *  此方法可在collectionView之后进行走的
 */
-(void)prepareLayout
{
    //设置格子的大小
    self.itemSize = CGSizeMake(CWItemH, CWItemH);

    CGFloat inset = (self.collectionView.frame.size.width-CWItemH)*0.5;

    self.sectionInset = UIEdgeInsetsMake(0, inset, 0, inset);

    self.minimumLineSpacing = 100;

   /**
    *  设置滑动方向
    *  UICollectionViewScrollDirectionHorizontal 水平方向
    *  UICollectionViewScrollDirectionVertical   垂直方向
    */
   self.scrollDirection = UICollectionViewScrollDirectionHorizontal;
  /*
    //        //设置最小行间距
    //        self.minimumLineSpacing = 10;
    //
    //        //设置最小列间距
    //        self.minimumInteritemSpacing = 10;
    //
    //        //设置与四周的边距
    //        self.sectionInset = UIEdgeInsetsMake(5, 5, 5, 5);

   */

   /**
    *  每一个cell(item)都有自己的UICollectionViewLayoutAttributes
    *  每一个indexPath都有自己的UICollectionViewLayoutAttributes
    */
}

/**
 *  用来设置collectionView停止滚动那一刻的位置
 *
 *  @param proposedContentOffset collectionView原本停留的位置
 *  @param velocity              滚动的速度
 */
-(CGPoint)targetContentOffsetForProposedContentOffset:(CGPoint)proposedContentOffset withScrollingVelocity:(CGPoint)velocity
{
    //1.计算scrollview最后会停留的范围
    CGRect lastRect;
    lastRect.origin = proposedContentOffset;
    lastRect.size = self.collectionView.frame.size;

    //计算屏幕最中间的x
    CGFloat centerX = proposedContentOffset.x + self.collectionView.frame.size.width*0.5;

  //2.取出这个范围内的所有属性
  NSArray *array1 = [self layoutAttributesForElementsInRect:lastRect];

  //遍历所有的属性
  CGFloat adjustOffsetX = MAXFLOAT;

  for (UICollectionViewLayoutAttributes *array2 in array1) {
  
  if (ABS(array2.center.x - centerX) < ABS(adjustOffsetX)) {
      
      adjustOffsetX = array2.center.x - centerX;
  }
 }
   return CGPointMake(proposedContentOffset.x+adjustOffsetX, proposedContentOffset.y);
 }

/**
 *  对collection的滚动进行实时监控
 *  只要显示的便捷发生改变就进行重新布局,内部会重新调用 layoutAttributesForElementsInRect:(CGRect)rect,获得所有cell的布局属性
 */
-(BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
    return YES;
}

 /**
  *  对传进来的item进行监听
  */
 -(NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect
 {
   //计算呢可见的矩形框
   CGRect visiableRect;

  visiableRect.size = self.collectionView.frame.size;
  visiableRect.origin = self.collectionView.contentOffset;
  //1.取出默认的cell的 UICollectionViewLayoutAttributes,super是返回所有的图片
  NSArray *array = [super layoutAttributesForElementsInRect:rect];

 //计算屏幕最中间的x

 CGFloat centerX = self.collectionView.contentOffset.x + self.collectionView.frame.size.width*0.5;

 //2.遍历所有的布局属性
  for (UICollectionViewLayoutAttributes *attributes in array) {
  
  if (!CGRectIntersectsRect(visiableRect, attributes.frame))
  {
      continue;
  }

  //每一个item中点的x
  CGFloat itemCenterX = attributes.center.x;
  
  //根据屏幕最中间的距离计算缩放比例,差距越小缩放比例越大
  CGFloat scale = 1+ 1 - ABS(itemCenterX - centerX)/(self.collectionView.frame.size.width*0.5);

  attributes.transform3D = CATransform3DMakeScale(scale, scale, scale);
 }

 return array;
}
 @end

2.建立UICollectionView(挂代理,遵守协议)
<UICollectionViewDataSource,UICollectionViewDelegate>

  /**
   *   UICollectionView的创建
   */
   UICollectionView *collectionView = [[UICollectionView alloc]initWithFrame:CGRectMake(0, 100, WIDTH, WIDTH) collectionViewLayout:layout];
   collectionView.backgroundColor = CWColor(255, 255, 0);
   collectionView.showsHorizontalScrollIndicator = NO;

   collectionView.delegate = self;
   collectionView.dataSource = self;
   /**
    *  注册UICollectionView
    */
  [collectionView registerNib:[UINib nibWithNibName:@"CWImageCell" bundle:nil] forCellWithReuseIdentifier:ID];
  [self.view addSubview: collectionView];

3.CollectionView的代理方法

 #pragma mark  collectionView的代理方法的实现
-(NSInteger )collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return self.imageArray.count;
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{

CWImageCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:ID forIndexPath:indexPath];

cell.imageName = self.imageArray[indexPath.item];

cell.number.text = [NSString stringWithFormat:@"%ld",(long)indexPath.item+1];

return cell;

}

/**
 *  collectionView的点击事件
 */
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    //删除模型数据(删除的指定item)
    [self.imageArray removeObjectAtIndex:indexPath.item];

    //刷新UI
    [collectionView deleteItemsAtIndexPaths:@[indexPath]];

}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
/**
 *  动画式切换
 */
if ([self.collectionView.collectionViewLayout isKindOfClass:[CwLineLayout class]]) {
    
    [self.collectionView setCollectionViewLayout:[[UICollectionViewFlowLayout alloc]init] animated:YES];
  }else
  {
       [self.collectionView setCollectionViewLayout:[[CwLineLayout alloc]init] animated:YES];
  }
}
#pragma mark 图片数组化
-(NSMutableArray *)imageArray
{
   if (!_imageArray) {
    
    _imageArray = [[NSMutableArray alloc]init];
    
    for (int i = 1; i <= 13 ; i++) {
        
        [_imageArray addObject:[NSString stringWithFormat:@"%d.jpg",i]];
    }
 }
  return _imageArray;
}

简单的相册demo 密码: fm69

实例2旋转相册密码:hwh3

旋转相册

值得注意的是layout的一个属性

// zIndex越大,就越在上面
attrs.zIndex = [self.collectionView numberOfItemsInSection:indexPath.section] - indexPath.item;

实例3.圆形角度相册密码: yj7w

圆形角度相册.gif

大总结:在进行layout 进行布局时记住如下几点:

1.继承方式

UICollectionViewFlowLayout 继承它就拥有流水的效果
UICollectionViewLayout 如果继承它,那么一切布局要从头开始

2.在第二种继承方式里面layout重新布局的类.m中不可缺少的方法(一般来说这3个方法不可缺少)

/**
 *  对collection的滚动进行实时监控
 *  只要显示的便捷发生改变就进行重新布局,内部会重新调用 layoutAttributesForElementsInRect:(CGRect)rect,获得所有cell的布局属性
 */
-(BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
      return YES;
}

/**
 *  位置改变就重新布局
 */
-(NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect
{
   NSMutableArray *array = [NSMutableArray array];

   NSInteger count = [self.collectionView numberOfItemsInSection:0];

  for (int i = 0; i < count; i++) {
 
      UICollectionViewLayoutAttributes *attrs = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:i inSection:0]];
 
      [array addObject:attrs];
   }
  return array;
}
//在此里面进行自己想要的设置
-(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
   UICollectionViewLayoutAttributes *attrs = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
   attrs.size = CGSizeMake(50,50);
   attrs.zIndex = indexPath.item;
   return attrs;
}

提示： UICollectionView 滚动条去掉

  垂直滚动条
  XXX.showsVerticalScrollIndicator = NO;
  水平滚动条
  XXX.showsHorizontalScrollIndicator = NO;

UICollectionView自定义相册

一.我们要对UICollectionView的布局进行自定义

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