[英]How to detect bottom of UITextView (UIScrollView) glitch in iOS
我正在使用惰性加载器,但遇到一个问题,即在我加载更多数据后, UITextView
认为它立即位于视图的底部,因此错误地设置了我的偏移量。
我只是试图加载新数据,并让UITextView
稍微向下滚动,以便用户知道已加载了更多数据。
码:
-(void)scrollViewDidScroll: (UIScrollView*)scrollView
{
float scrollViewHeight = scrollView.frame.size.height;
float scrollContentSizeHeight = scrollView.contentSize.height;
float yOffset = scrollView.contentOffset.y;
NSLog(@"yOffset + scrollViewHeight = %f",yOffset + scrollViewHeight);
NSLog(@"yOffset = %f",yOffset );
if (yOffset == 0) {
// then we are at the top
}
else if (yOffset + scrollViewHeight == scrollContentSizeHeight) {
if (self.updateInProgress) {
NSLog(@"updateInProgress");
return;
}
// then we are at the end
self.updateInProgress = TRUE;
NSLog(@"scrollContentSizeHeight = %f",scrollView.contentSize.height);
NSLog(@" === at bottom of scrollview ===");
// JUST NEED TO FIX WHERE SCROLLVIEW APPEARS!
self.TextView.text = [NSString stringWithFormat:@"%@\n\n%@",self.TextView.text, self.nextChapterString];
CGPoint offset = self.TextView.contentOffset;
offset.y = yOffset + scrollViewHeight + 100;
[self.TextView setContentOffset:offset animated:NO];
//NSLog(@"updated TextView = %@", self.TextView.text);
// since disabled scrolling while updating, force scroll down a bit
// CGPoint offset = scrollView.contentOffset;
// offset.y += 100;
// [scrollView setContentOffset:offset animated:YES];
}
self.updateInProgress = FALSE;
}
OUTPUT:
这是我看到的输出,如您所见,在加载更多数据后,我的yOffset发生了巨大变化。
2014-05-07 23:11:40.370 Test[6314:60b] yOffset + scrollViewHeight = 1821.500000
2014-05-07 23:11:40.370 Test[6314:60b] yOffset = 1432.500000
2014-05-07 23:11:40.371 Test[6314:60b] yOffset = 389.000000
2014-05-07 23:11:40.403 Test[6314:60b] yOffset + scrollViewHeight = 1821.000000
2014-05-07 23:11:40.403 Test[6314:60b] yOffset = 1432.000000
2014-05-07 23:11:40.404 Test[6314:60b] yOffset = 389.000000
2014-05-07 23:11:40.470 Test[6314:60b] yOffset + scrollViewHeight = 1820.500000
2014-05-07 23:11:40.471 Test[6314:60b] yOffset = 1431.500000
2014-05-07 23:11:40.471 Test[6314:60b] yOffset = 389.000000
2014-05-07 23:11:40.504 Test[6314:60b] yOffset + scrollViewHeight = 1820.000000
2014-05-07 23:11:40.505 Test[6314:60b] yOffset = 1431.000000
2014-05-07 23:11:40.505 Test[6314:60b] yOffset = 389.000000
2014-05-07 23:11:40.506 Test[6314:60b] scrollContentSizeHeight = 1820.000000
2014-05-07 23:11:40.506 Test[6314:60b] === at bottom of scrollview ===
2014-05-07 23:11:40.508 Test[6314:60b] yOffset + scrollViewHeight = 2309.000000
2014-05-07 23:11:40.508 Test[6314:60b] yOffset = 1920.000000
2014-05-07 23:11:40.508 Test[6314:60b] yOffset = 389.000000
2014-05-07 23:11:40.509 Test[6314:60b] yOffset + scrollViewHeight = 1954.000000
2014-05-07 23:11:40.509 Test[6314:60b] yOffset = 1565.000000
2014-05-07 23:11:40.510 Test[6314:60b] yOffset = 389.000000
2014-05-07 23:11:40.510 Test[6314:60b] scrollContentSizeHeight = 1954.000000
2014-05-07 23:11:40.510 Test[6314:60b] === at bottom of scrollview ===
2014-05-07 23:11:40.512 Test[6314:60b] yOffset + scrollViewHeight = 2443.000000
2014-05-07 23:11:40.512 Test[6314:60b] yOffset = 2054.000000
2014-05-07 23:11:40.513 Test[6314:60b] yOffset = 389.000000
关于我在做什么错的任何建议吗?
尝试这个
text.text = [NSString stringWithFormat:@"%@\n\n%@",text.text, str];
CGPoint offset = text.contentOffset;
offset.y = yOffset + scrollViewHeight + 100;
text.delegate = nil;//set your delegate nil
[text setContentOffset:offset animated:NO];
text.delegate = self;//set back
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