I'm going to explain about a custom textview control with hovering.

The scenario which directed me to build up a control like this as follows. Let's say you have a textview (max number of lines: 1) with a limited width. When you set a lengthy text on it, it will automatically truncate some part of the text and add 3 dots (...) towards the end.

The solution which I proposed would work like this. Say you have a textview with a lengthy text. When you tap and hold it, it'll bring up the entire text (without any truncation) in a hover view/separate view.

Example: A textview with a lengthy text.

When you tap and hold the textview...

Now I'm going to the details of the actual implementation.

.h file

#import <UIKit/UIKit.h>

@interface CustomTextView : UITextView

@property(atomic, weak) UIViewController* currentViewController;
@property(atomic, strong) UIView* hoverView;

@end

.m file

#import <Foundation/Foundation.h>
#import "CustomTextView.h"
#import "UIHelper.h"


@implementation CustomTextView

- (id)initWithCoder:(NSCoder *)aDecoder{
    self = [super initWithCoder:aDecoder];
    if (self)
        [self initialSetup];
    return self;
}

- (id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self)
        [self initialSetup];
    return self;
}

- (void)onLongPress:(UILongPressGestureRecognizer *) longPressGestureRecognizer{
    if (longPressGestureRecognizer.state == UIGestureRecognizerStateBegan){
        if(longPressGestureRecognizer.view != nil){
            if ([longPressGestureRecognizer.view isKindOfClass:[UITextView class]]) {
                UITextView *textView = (UITextView*)longPressGestureRecognizer.view;
                self.currentViewController = self.window.rootViewController;
                NSString *text = textView.text;

                CGSize sizeRequired = [textView.text sizeWithAttributes:@{NSFontAttributeName :textView.font}];
                CGFloat widthRequired = sizeRequired.width;
                CGFloat widthAvailable = textView.bounds.size.width;
                if(widthRequired <= widthAvailable) return;

                [textView sizeToFit];

                CGFloat navigationBarHeight = 0;
                if(self.currentViewController.navigationController.navigationBar != nil) navigationBarHeight = self.currentViewController.navigationController.navigationBar.frame.size.height;
                CGFloat toolbarHeight = 0;
                UIToolbar *toolbar = [UIHelper findToolbar:self.currentViewController.view];
                if (toolbar != nil) toolbarHeight = toolbar.frame.size.height;
                CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
                CGFloat availableHeight = screenHeight - (navigationBarHeight + toolbarHeight);
                CGPoint currentRelativePoint = [self.currentViewController.view convertPoint:textView.frame.origin toView:nil];
                CGRect originalRect = textView.frame;
                CGFloat currentYPos = (currentRelativePoint.y + originalRect.size.height);


                UITextView *innerTextView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, originalRect.size.width, originalRect.size.height)];
                [innerTextView setFont:[UIFont systemFontOfSize:12]];
                [innerTextView setText:text];
                [innerTextView setFrame:CGRectMake(0, 0, originalRect.size.width, innerTextView.contentSize.height)];

                CGRect innerRect = innerTextView.frame;
                if ((availableHeight - currentYPos) >= innerRect.size.height)
                    self.hoverView = [[UIView alloc] initWithFrame:CGRectMake(originalRect.origin.x, (originalRect.origin.y + originalRect.size.height), innerRect.size.width, innerRect.size.height)];
                else
                    self.hoverView = [[UIView alloc] initWithFrame:CGRectMake(originalRect.origin.x, (originalRect.origin.y - innerRect.size.height), innerRect.size.width, innerRect.size.height)];
                [self.hoverView.layer setBorderColor:[UIColor purpleColor].CGColor];
                [self.hoverView.layer setBorderWidth:1];
                [self.hoverView.layer setCornerRadius:4];              
                [self.hoverView addSubview:innerTextView];
                [textView.superview addSubview:self.hoverView];
            }
        }
    }
    else{
        if (longPressGestureRecognizer.state == UIGestureRecognizerStateCancelled
            || longPressGestureRecognizer.state == UIGestureRecognizerStateFailed
            || longPressGestureRecognizer.state == UIGestureRecognizerStateEnded){
            if (self.hoverView != nil){
                UITextView *innerTextView = [self.hoverView subviews][0];
                NSMutableArray *words = [NSMutableArray arrayWithArray:[innerTextView.text componentsSeparatedByCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]];
                NSInteger wordCount = [words count];
                double noOfWordsPerSec = 3.33;//average readers are the majority and only reach around 200 wpm.
                double noOfSecsRequired = (ceil)(wordCount/noOfWordsPerSec);
                double bonusSecs = 1.0;

                [UIView animateWithDuration:1 delay:(noOfSecsRequired + bonusSecs) options:0
                                 animations:^{
                                     [self.hoverView setAlpha:0.0f];
                                 }
                                 completion:^(BOOL finished){
                                     if (finished)
                                         [self.hoverView removeFromSuperview];
                                 }];
            }
        }
    }
}

- (void)initialSetup{
    self.textContainer.maximumNumberOfLines = 1;
    self.textContainer.lineBreakMode = NSLineBreakByTruncatingTail;
    self.scrollEnabled = false;
    self.editable = FALSE;
    self.selectable = FALSE;
    [self setDataDetectorTypes:UIDataDetectorTypeAll];

    for (UIGestureRecognizer *recognizer in self.gestureRecognizers){
        if ([recognizer isKindOfClass:[UILongPressGestureRecognizer class]]){
            recognizer.enabled = NO;
        }
    }

    UILongPressGestureRecognizer *longPressGesRec = [[UILongPressGestureRecognizer alloc]
                                                     initWithTarget:self
                                                     action:@selector(onLongPress:)];
    [self addGestureRecognizer:longPressGesRec];
}

- (void)awakeFromNib{
    [super awakeFromNib];
}

@end

Usage:

CustomTextView *ctv = [[CustomTextView alloc] initWithFrame:CGRectMake(65, 300, 150, 30)];
ctv.text = @"replace this with a lengthy text.....";
[self.view addSubview:ctv];

Please note the following:

1. The width of the hover view is matched with the width of the textview.
2. Depending on the available height, the hover view will appear above or below the textview.
3. The hover view will automatically fade away after a certain amount of time - the displaying time will be calculated based on the number of words in the given text.

Thank you and happy coding... :)