iOS tableView高度緩衝

標籤：dict   turn   rect   mat   led   緩衝   計算   Dimension   不必要   

tableView計算完高度後，把高度緩衝起來，避免下次重複計算，以減少不必要的消耗

// declare cellHeightsDictionaryNSMutableDictionary *cellHeightsDictionary; // initialize in code (thanks to @Gerharbo)cellHeightsDictionary = @{}.mutableCopy; // declare table dynamic row height and create correct constraints in cellstableView.rowHeight = UITableViewAutomaticDimension; // save height- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {    [cellHeightsDictionary setObject:@(cell.frame.size.height) forKey:indexPath];} // give exact height value- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath {    NSNumber *height = [cellHeightsDictionary objectForKey:indexPath];    if (height) return height.doubleValue;    return UITableViewAutomaticDimension;}

iOS tableView高度緩衝