自定义瀑布流

#define kWidth self.frame.size.width

#define kHeight self.frame.size.height

@interface
JRScrollView()

@property (nonatomic,
strong) NSMutableArray * frameArray;

@property (nonatomic,
strong) NSMutableDictionary * temDic;

@property (nonatomic,
strong) NSMutableSet * temSet;

@property (nonatomic,
strong) NSMutableDictionary * inDic;

@end

@implementation JRScrollView

//懒加载
- (NSMutableArray *)frameArray
{

if (_frameArray ==
nil)
{

_frameArray = [NSMutableArray
array];
}

return
_frameArray;
}

- (NSMutableDictionary *)temDic
{

if (_temDic ==
nil)
{

_temDic = [NSMutableDictionary
dictionary];
}

return
_temDic;
}

- (NSMutableSet *)temSet
{

if (_temSet ==
nil)
{

_temSet = [NSMutableSet
set];
}

return
_temSet;
}

- (NSMutableDictionary *)inDic
{

if (_inDic ==
nil)
{

_inDic = [NSMutableDictionary
dictionary];
}

return _inDic;
}

//初始化
- (instancetype)initWithFrame:(CGRect)frame
{

if (self = [super
initWithFrame:frame])
{

self.showsVerticalScrollIndicator =
NO;

self.backgroundColor = [UIColor
whiteColor];
}

return
self;
}

//加载数据
- (void)loadDataWithArray:(NSMutableArray *)array
{

//获得列数

NSInteger colums =
3;

if ([self.delegateMe
respondsToSelector:@selector(numberOfColums:)])
{
colums = [self.delegateMe
numberOfColums:self];
}

//获取cell数

NSInteger count =
0;

if ([self.dataSourceMe
respondsToSelector:@selector(numberOfCell:)])
{
count = [self.dataSourceMe
numberOfCell:self];
}

//计算左右间距

CGFloat marginLR =
10;

//计算上下间距

CGFloat marginUD = marginLR;

//计算cell宽度

CGFloat cellW = (kWidth-marginLR*(colums+1))/colums;

//标记每一列的做大Y值

NSMutableArray * maxYAry = [NSMutableArray
array];

for (int i =
0; i<colums; i++)
{

NSMutableDictionary * dic = [NSMutableDictionary
dictionary];
[dic
setObject:@(0)
forKey:@"maxY"];

//计算放在这一列的x坐标

CGFloat cellX = (cellW+marginLR)*i+marginLR;
[dic
setObject:@(cellX)
forKey:@"cellX"];

//添加数组
[maxYAry
addObject:dic];
}

//计算高度和坐标

for (int i =
0; i<count; i++)
{

JRCellModel * model = array[i];

//计算cell高度

CGFloat cellH = model.h*cellW/model.w;

//获取maxY最小的一列
[maxYAry
sortUsingComparator:^NSComparisonResult(id obj1,
id obj2)
{

return [obj1[@"maxY"]
doubleValue] - [obj2[@"maxY"]
doubleValue];
}];

NSMutableDictionary * dic = [maxYAry
firstObject];

//cell放在那一列（x值）

CGFloat cellX = [dic[@"cellX"]
doubleValue];

//cell的y值

CGFloat cellY = [dic[@"maxY"]
intValue] + marginUD;

//更新这个字典的属性

CGFloat tempY = cellY+cellH;
[dic
setObject:@(tempY)
forKey:@"maxY"];

//创建frame，加入数组

CGRect frame = CGRectMake(cellX, cellY, cellW, cellH);

[self.frameArray
addObject:[NSValue
valueWithCGRect:frame]];

//计算contentsize

if (i == count - 1)
self.contentSize =
CGSizeMake(kWidth, tempY+marginUD);

}

//布局
- (void)layoutSubviews
{

[super
layoutSubviews];

//判断frame在不在视野中

BOOL isIn;

for (int i =
0; i<self.frameArray.count; i++)
{

CGRect frame = [self.frameArray[i]
CGRectValue];

CGFloat offsetY =
self.contentOffset.y;
isIn = offsetY<CGRectGetMaxY(frame) && (offsetY+self.frame.size.height)>CGRectGetMinY(frame);

//在，新添加的（原来有的不处理）

if(isIn)
{

if(!self.inDic[@(i)])
{

//添加新的视图

JRCell * cell = [self.dataSourceMe
scroll:self
cellAtIndex:i];
cell.frame = [self.frameArray[i]
CGRectValue];
[self
addSubview:cell];

//处理inDic字典
[self.inDic
setObject:cell forKey:@(i)];
}
}

//不在，新删除的（一直不在的不处理）

else
{

JRCell * cell = self.inDic[@(i)];

if(cell)
{

NSMutableSet * set =
self.temDic[cell.reuseableID];
[set
addObject:cell];

[self.inDic
removeObjectForKey:@(i)];
[cell
removeFromSuperview];
}
}
}
}

//重复利用
- (JRCell *)dequWithReusedableID:(NSString *)ID
{

NSMutableSet * set =
self.temDic[ID];

if (!set)
{
set = [NSMutableSet
set];
[self.temDic
setObject:set forKey:ID];
}

// NSLog(@"%li", set.count);

JRCell * cell = [set
anyObject];

if (cell)
{
[set
removeObject:cell];
}

return cell;
}

@end