uiscrollview - UITextView、setContentOffset 和缺少底部

Question

出于某种奇怪的原因，当设置 scrollofset 时，我的 UITextView 的文本显示为裁剪。

这是它的样子:


执行以下操作后会发生这种情况:

        textview.contentInset = UIEdgeInsetsZero;
        [textview setContentOffset:CGPointMake(0, startypos + offset_yshift) animated:NO];

我尝试手动设置 contentSize.height，但这引入了另一种奇怪的行为，内容偏移似乎被忽略了..

''Edit'':这是用于实例化文本字段的代码:

  CGRect myImageRect = CGRectMake(-50.0f, -50.0f, 40.0f, 40.0f);
  textview = [[UITextView alloc] initWithFrame: myImageRect];
  textview.autocapitalizationType = UITextAutocapitalizationTypeNone;
  [textview setScrollEnabled:YES];
  textview.hidden = YES;
  textview.contentInset = UIEdgeInsetsZero;
  textview.opaque = NO;
  textview.backgroundColor = [UIColor clearColor];
  textview.textColor = [UIColor colorWithWhite:1 alpha:1];
  textview.textAlignment = NSTextAlignmentCenter;
  textview.frame = CGRectMake(0, 0, 250, 30);
  textview.scrollEnabled = NO;

以及检查每一帧内容定位的“更新”代码:

  // setting the actual size here
  UITextPosition * pos = [textview positionFromPosition: textview.endOfDocument offset:nil];
  CGRect therect = [textview caretRectForPosition:pos];

  CGRect frame = textview.frame;

  if([textview.text length] == 0){
     frame.size.height = 30;
  } else {
     frame.size.height = therect.origin.y + therect.size.height;
  }

  // and here, we're changing the frame variable's height to max to 50
  if(frame.size.height > 50){
     frame.size.height = 50;
  }
  frame.size.width = desiredwidth; // some other variable

  textview.frame = frame;

  /*

     ... snip, unrelated code ...

  */

  // later on

        textview.contentInset = UIEdgeInsetsZero;
        [textview setContentOffset:CGPointMake(0, startypos + offset_yshift) animated:NO];

可以想象， setContentOffset 位是导致问题的原因。

到底是怎么回事？

Answer 1

请从上一篇文章中尝试这个

CGPoint offset = CGPointMake(0, self.textView.contentSize.height - self.textView.frame.size.height);
[self.textView setContentOffset: CGPointMake(0,0) animated:NO]; 
or
[self.textView setContentOffset:bottomOffset animated:YES];

【发帖】: UITextView contentOffset on iOS 7 “上一篇”\