iOS8 使用动画更改帧时 UITextView 光标低于帧

Question

我正在尝试在键盘上方显示光标 并使用一些动画 还试图正确滚动 UITextView 背景线。

我已经在 iOS 7 中使用下面的代码完美地解决了这个问题，但它在 iOS 8 上崩溃了，我认为原因是我试图覆盖 scrollRangeToVisible 在 iOS8 中，但我无法这样做，它不像在 iOS7 中那样自动调用。触摸 UITextView 时会显示键盘，因此我无法控制如何滚动内容。我的 UITextView 也有线条。

- (void)textViewDidBeginEditing:(UITextView *)aTextView
{
    caretVisibilityTimer = [NSTimer scheduledTimerWithTimeInterval:0.2 target:self selector:@selector(scrollCaretToVisible) userInfo:nil repeats:NO];
}

- (void)textViewDidEndEditing:(UITextView *)aTextView
{
    [caretVisibilityTimer invalidate];

    caretVisibilityTimer = nil;
}

-(void) scrollRangeToVisible: (NSRange) range {
    printf("scrollRangeToVisible \n");
}

- (void) scrollCaretToVisible {
    printf("scrollCaretToVisible \n");

    //[self becomeFirstResponder];

    //This is where the cursor is at.
    CGRect caretRect = [self caretRectForPosition: self.selectedTextRange.end];

    if (CGRectEqualToRect(caretRect, oldRect))
        return;

    oldRect = caretRect;

    //This is the visible rect of the textview.
    CGRect visibleRect = self.bounds;

    visibleRect.size.height -= (self.contentInset.top + self.contentInset.bottom);

    visibleRect.origin.y = self.contentOffset.y;

    //We will scroll only if the caret falls outside of the visible rect.
    if (!CGRectContainsRect(visibleRect, caretRect)) {
        CGPoint newOffset = self.contentOffset;

        newOffset.y = MAX((caretRect.origin.y + caretRect.size.height) - visibleRect.size.height, 0);

        //Added This section
        //=======================================
        // Calculates new contentOffset
        if (caretRect.origin.y < visibleRect.origin.y)
        // rect precedes bounds, scroll up
            newOffset.y = caretRect.origin.y - self.contentInset.top - self.bottomPadding;

        else
        // rect follows bounds, scroll down
            newOffset.y = caretRect.origin.y + self.contentInset.bottom + caretRect.size.height - self.bounds.size.height;
        //=======================================

        /* */
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^ (void)
            //dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0), dispatch_get_main_queue(), ^(void)
            {
                [UIView beginAnimations: nil context: NULL];
                [UIView setAnimationDuration: 0.5];
                [UIView setAnimationCurve: UIViewAnimationCurveLinear];
                [self setContentOffset: newOffset animated: YES];
                [UIView commitAnimations];
            });

        //[self setContentOffset:newOffset animated:YES];
    }
}

参考 UITextView cursor below frame when changing frame

Answer 1

如果有人感兴趣，我发现对于 iOS8，我需要覆盖 scrollRectToVisible，这相当于覆盖 iOS7

中的 scrollRangeToVisible

iOS7

- (void) scrollRangeToVisible:(NSRange)range { }

iOS8

- (void) scrollRectToVisible:(CGRect)rect animated:(BOOL)animated{ [self scrollCaretToVisible]; }

iOS8 使用动画更改帧时 UITextView 光标低于帧

iOS8 UITextView cursor below frame when changing frame with Animation

ios

ios8

uitextview