相关疑难解决方法(0)

我通过扩展UITextView来实现自定义的富文本编辑器.当用户选择文本范围并使用"突出显示"菜单时,编辑器将为所选文本绘制蓝色背景:

- (CGRect)getRectAtRangePos:(NSInteger)pos {
    UITextPosition *beginning = self.beginningOfDocument;
    UITextPosition *start = [self positionFromPosition:beginning offset:pos];
    CGRect rect = [self caretRectForPosition:start];
    return [self convertRect:rect fromView:self.textInputView];
}


- (void)drawRange:(NSRange)range {
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetRGBFillColor(context, 0x16/255.f, 0x38/255.f, 0xfc/255.f, 0.5);
    CGRect startRect = [self getRectAtRangePos:range.location];
    CGRect endRect = [self getRectAtRangePos:range.location + range.length];

    CGFloat padding = 1;
    CGFloat margin = 1;

    if (ABS(endRect.origin.y - startRect.origin.y) < 5) {//They are in the same line
        CGRect wholeRect = CGRectMake(startRect.origin.x, startRect.origin.y + padding, endRect.origin.x - startRect.origin.x, startRect.size.height - …