ios - UITextView firstRectForRange 返回错误的框架

Question

编辑

简单的解决方案是将任何帧计算从 viewDidLoad 移动到 viewDidAppear:

---

我很难让下面的代码正常工作

代码返回 UITextView 中给定 NSRange 的第一帧。

如果没有换行符它会工作，但是当我在 UITextView 中添加换行符时我会得到一些奇怪的行为。

@implementation UITextView (TextFrame)

- (CGRect)frameOfTextRange:(NSRange)range {
    UITextPosition *beginning = self.beginningOfDocument;
    UITextPosition *start = [self positionFromPosition:beginning offset:range.location];
    UITextPosition *end = [self positionFromPosition:start offset:range.length];
    UITextRange *textRange = [self textRangeFromPosition:start toPosition:end];
    CGRect rect = [self firstRectForRange:textRange];

    return [self convertRect:rect fromView:self.textInputView];
}

@end

@implementation DetailViewController

- (void)viewDidLoad 
{
    [super viewDidLoad];
   if (self.searchString) {
        CGRect rect = [self.textView frameOfTextRange:[self.textView.text rangeOfString:self.searchString]];
        ...
    }
}

Answer 1

我发现以下解决方案有效。我没有使用仅返回一个矩形的 firstRectForRange:，而是使用 selectionRectsForRange:，然后遍历所有矩形并使用 CGRectUnion 将它们组合起来.

- (CGRect)frameOfTextRange:(NSRange)range
{
   UITextPosition *beginning = self.beginningOfDocument;
   UITextPosition *start = [self positionFromPosition: beginning offset: range.location];
   UITextPosition *end = [self positionFromPosition: start offset: range.length];

   UITextRange *textRange = [self textRangeFromPosition: start toPosition: end];

   CGRect  rect = CGRectZero;

   NSArray *selectionRects = [self selectionRectsForRange: textRange];

   for (UITextSelectionRect *selectionRect in selectionRects)
   {
      rect = CGRectUnion(rect, selectionRect.rect);
   }

   return rect;
}