如果我在UITableViewCell中有一个带有排除路径的TextView,我如何计算给定字符串的单元格高度？
解决方法
我找到了一个我认为可能对其他人有帮助的解决方案.由于它不需要创建新的NSTextContainer,NSLayoutManager和NSTextStorage对象,它们已经被实例化为UITextView的一部分,我怀疑它会更有效率.
要计算使用排除路径和NSAttributedString的UITextView的大小,可以执行以下操作：
- // Assuming something like this...
- UIBezierPath * exclusionPath = [UIBezierPath bezierPathWithRect:someRect];
- self.textView.textContainer.exclusionPaths = @[exclusionPath];
- NSAttributedString * attributedString = ...
- self.textView.attributedString = attributedString;
- ...
- // Use text container,layout manager,and text storage associated with the text view.
- NSTextContainer * textContainer = self.textView.textContainer;
- NSLayoutManager * layoutManager = textContainer.layoutManager;
- NSTextStorage * textStorage = layoutManager.textStorage;
- // Limit the width or height. In this case,limiting the width to 280.
- textContainer.size = CGSizeMake(280.0,FLT_MAX);
- [textStorage setAttributedString:attributedString];
- // Because the layout manager performs layout lazily,on demand,you must force it to lay out the text,even though you don’t need the glyph range returned by this function.
- [layoutManager glyphRangeForTextContainer:textContainer];
- // Ask the layout manager for the height of the rectangle occupied by the laid-out text
- CGFloat height = [layoutManager usedRectForTextContainer:textContainer].size.height;
