iOS实现比例拼图的方法示例

{
 "result": true,
 "data": {
 "category_sale": [ {
  "name": "我是你的哥",
  "sale_amount": 1,
  "gross_margin_ratio": 0.22
 }, {
  "name": "不是亲哥哥",
  "sale_amount": 4,
  "gross_margin_ratio": 0
 }, {
  "name": "呵呵哒",
  "sale_amount": 3,
  "gross_margin_ratio": 0.19
 }, {
  "name": "因缺思厅",
  "sale_amount": 2,
  "gross_margin_ratio": 0.4
 }]
 },
 "msg": "ok",
 "code": 200,
 "executed": "0.0320830345"
}

- (void)setModel:(CQCategoryModel *)model {
 _model = model;
 
 CGFloat totalSaleAmount = 0;
 for (CQCategoryItemModel *itemModel in _model.category_sale) {
 totalSaleAmount += itemModel.sale_amount;
 }
 
 for (CQCategoryItemModel *itemModel in _model.category_sale) {
 if (totalSaleAmount == 0) {
  // 特殊处理只有一个item，并且SaleAmount还是0的情况
  itemModel.ratio = 1;
 } else {
  itemModel.ratio = itemModel.sale_amount/totalSaleAmount;
 }
 }
 
 // 计算列数
 NSInteger listCount = 0;
 for (int i = 0; i < _model.category_sale.count; i++) {
 if (i * i < _model.category_sale.count && (i+1) * (i+1) >= _model.category_sale.count) {
  listCount = i+1;
  break;
 }
 }
 
 // 计算行数
 NSInteger rowCount = ceil(_model.category_sale.count / (CGFloat)listCount);
 
 // 这个方阵是listCount*rowCount的矩阵（最后一排可能不足listCount）
 // 同一排的cell高度相同
 for (int i = 0; i < rowCount; i++) { // 行
 CGFloat rowArea = 0; // 行面积
 for (int j = 0; j < listCount; j++) { // 列
  if (i*listCount+j>=_model.category_sale.count) {
  break;
  }
  CQCategoryItemModel *itemModel = _model.category_sale[i*listCount+j];
  itemModel.size = itemModel.ratio * (self.collectionView.width*self.collectionView.width);
  rowArea += itemModel.size;
 }
 // 计算cell的宽高
 for (int j = 0; j < listCount; j++) { // 列
  if (i*listCount+j>=_model.category_sale.count) {
  break;
  }
  CQCategoryItemModel *itemModel = _model.category_sale[i*listCount+j];
  itemModel.height = rowArea / self.collectionView.width;
  itemModel.width = itemModel.size / itemModel.height;
 }
 }
 
 [self.collectionView reloadData];
}

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
 CQCategoryItemModel *model = self.model.category_sale[indexPath.row];
 // 减去0.01，避免因小数不精确存储导致一组cell宽度相加超过collectionView的宽度
 return CGSizeMake(model.width-0.01, model.height);
}