#pragma mark - 动态计算cell高度
+ (CGFloat)kCalculation_HeightForCellWithTableView:(UITableView *)tableView byIdentifier:(NSString *)identifier configuration:(void (^)(id cell))configuration {
NSAssert(identifier.length > 0, @"Expect a valid identifier - %@", identifier); NSMutableDictionary*templateCellsByIdentifiers = objc_getAssociatedObject(tableView, _cmd);
if (!templateCellsByIdentifiers) {
templateCellsByIdentifiers = @{}.mutableCopy;
objc_setAssociatedObject(tableView, _cmd, templateCellsByIdentifiers, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
UITableViewCell *cell = templateCellsByIdentifiers[identifier];
if (!cell) {
cell = [tableView dequeueReusableCellWithIdentifier:identifier];
NSAssert(cell != nil, @"Cell must be registered to table view for identifier - %@", identifier);
cell.contentView.translatesAutoresizingMaskIntoConstraints = NO;
templateCellsByIdentifiers[identifier] = cell;
}
[cell prepareForReuse];
if (configuration) {
configuration(cell);
}
CGFloat contentViewWidth = CGRectGetWidth(tableView.frame);
if (cell.accessoryView) {
contentViewWidth -= 16 + CGRectGetWidth(cell.accessoryView.frame);
} else {
static const CGFloat systemAccessoryWidths[] = {
[UITableViewCellAccessoryNone] = 0,
[UITableViewCellAccessoryDisclosureIndicator] = 34,
[UITableViewCellAccessoryDetailDisclosureButton] = 68,
[UITableViewCellAccessoryCheckmark] = 40,
[UITableViewCellAccessoryDetailButton] = 48
};
contentViewWidth -= systemAccessoryWidths[cell.accessoryType];
}
CGFloat fittingHeight = 0;
if (contentViewWidth > 0) {
NSLayoutConstraint *widthFenceConstraint = [NSLayoutConstraint constraintWithItem:cell.contentView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:contentViewWidth];
[cell.contentView addConstraint:widthFenceConstraint];
fittingHeight = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
[cell.contentView removeConstraint:widthFenceConstraint];
}
if (fittingHeight == 0) {
fittingHeight = 44;
}
return fittingHeight;
}