Center text vertically in a UITextView
IphoneObjective CIosXcodeUitextviewIphone Problem Overview
I want to center the text vertically inside a big UITextView
that fills the whole screen - so that when there's little of text, say a couple of words, it is centered by height.
It's not a question about centering the text (a property that can be found in IB) but about putting the text vertically right in the middle of UITextView
if the text is short, so there are no blank areas in the UITextView
.
Can this be done? Thanks in advance!
Iphone Solutions
Solution 1 - Iphone
First add an observer for the contentSize
key value of the UITextView
when the view is loaded:
- (void) viewDidLoad {
[textField addObserver:self forKeyPath:@"contentSize" options:(NSKeyValueObservingOptionNew) context:NULL];
[super viewDidLoad];
}
Then add this method to adjust the contentOffset
every time the contentSize
value changes:
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
UITextView *tv = object;
CGFloat topCorrect = ([tv bounds].size.height - [tv contentSize].height * [tv zoomScale])/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
tv.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
}
Solution 2 - Iphone
Because UIKit is not KVO compliant, I decided to implement this as a subclass of UITextView
which updates whenever the contentSize
changes.
It's a slightly modified version of Carlos's answer which sets the contentInset
instead of the contentOffset
. In addition to being compatible with iOS 9, it also seems to be less buggy on iOS 8.4.
class VerticallyCenteredTextView: UITextView {
override var contentSize: CGSize {
didSet {
var topCorrection = (bounds.size.height - contentSize.height * zoomScale) / 2.0
topCorrection = max(0, topCorrection)
contentInset = UIEdgeInsets(top: topCorrection, left: 0, bottom: 0, right: 0)
}
}
}
Solution 3 - Iphone
If you don't want to use KVO you can also manually adjust offset with exporting this code to a function like this :
-(void)adjustContentSize:(UITextView*)tv{
CGFloat deadSpace = ([tv bounds].size.height - [tv contentSize].height);
CGFloat inset = MAX(0, deadSpace/2.0);
tv.contentInset = UIEdgeInsetsMake(inset, tv.contentInset.left, inset, tv.contentInset.right);
}
and calling it in
-(void)textViewDidChange:(UITextView *)textView{
[self adjustContentSize:textView];
}
and every time you edit the text in the code. Don't forget to set the controller as the delegate
Swift 3 version:
func adjustContentSize(tv: UITextView){
let deadSpace = tv.bounds.size.height - tv.contentSize.height
let inset = max(0, deadSpace/2.0)
tv.contentInset = UIEdgeInsetsMake(inset, tv.contentInset.left, inset, tv.contentInset.right)
}
func textViewDidChange(_ textView: UITextView) {
self.adjustContentSize(tv: textView)
}
Solution 4 - Iphone
For iOS 9.0.2. we'll need to set the contentInset instead. If we KVO the contentOffset, iOS 9.0.2 sets it to 0 at the last moment, overriding the changes to contentOffset.
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
UITextView *tv = object;
CGFloat topCorrect = ([tv bounds].size.height - [tv contentSize].height * [tv zoomScale])/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
[tv setContentInset:UIEdgeInsetsMake(topCorrect,0,0,0)];
}
- (void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:NO];
[questionTextView addObserver:self forKeyPath:@"contentSize" options:(NSKeyValueObservingOptionNew) context:NULL];
}
I used 0,0, and 0 for the left,bottom and right edge insets respectively. Make sure to calculate those as well for your use case.
Solution 5 - Iphone
Here's a UITextView
extension that centers content vertically:
extension UITextView {
func centerVertically() {
let fittingSize = CGSize(width: bounds.width, height: CGFloat.max)
let size = sizeThatFits(fittingSize)
let topOffset = (bounds.size.height - size.height * zoomScale) / 2
let positiveTopOffset = max(0, topOffset)
contentOffset.y = -positiveTopOffset
}
}
Solution 6 - Iphone
You can set it up directly with only constraints:
There are 3 constraints i added to align text vertically and horizontally in constraints as below :
- Make height 0 and add constraints greater than
- Add vertically align to parent constraints
- Add horizontally align to parent constraints
Solution 7 - Iphone
It is the simple task using NSLayoutManager
to get real text size of the NSTextContainer
class VerticallyCenteredTextView: UITextView {
override func layoutSubviews() {
super.layoutSubviews()
let rect = layoutManager.usedRect(for: textContainer)
let topInset = (bounds.size.height - rect.height) / 2.0
textContainerInset.top = max(0, topInset)
}
}
Don't use contentSize
and contentInset
in your final calculations.
Solution 8 - Iphone
I just created a custom vertically centered text view in Swift 3:
class VerticallyCenteredTextView: UITextView {
override var contentSize: CGSize {
didSet {
var topCorrection = (bounds.size.height - contentSize.height * zoomScale) / 2.0
topCorrection = max(0, topCorrection)
contentInset = UIEdgeInsets(top: topCorrection, left: 0, bottom: 0, right: 0)
}
}
}
Ref: https://geek-is-stupid.github.io/2017-05-15-how-to-center-text-vertically-in-a-uitextview/
Solution 9 - Iphone
func alignTextVerticalInTextView(textView :UITextView) {
let size = textView.sizeThatFits(CGSizeMake(CGRectGetWidth(textView.bounds), CGFloat(MAXFLOAT)))
var topoffset = (textView.bounds.size.height - size.height * textView.zoomScale) / 2.0
topoffset = topoffset < 0.0 ? 0.0 : topoffset
textView.contentOffset = CGPointMake(0, -topoffset)
}
Solution 10 - Iphone
I have a textview that I'm using with autolayout and with setting the lineFragmentPadding
and textContainerInset
to zero. None of the solutions above worked in my situation. However, this works for me. Tested with iOS 9
@interface VerticallyCenteredTextView : UITextView
@end
@implementation VerticallyCenteredTextView
-(void)layoutSubviews{
[self recenter];
}
-(void)recenter{
// using self.contentSize doesn't work correctly, have to calculate content size
CGSize contentSize = [self sizeThatFits:CGSizeMake(self.bounds.size.width, CGFLOAT_MAX)];
CGFloat topCorrection = (self.bounds.size.height - contentSize.height * self.zoomScale) / 2.0;
self.contentOffset = CGPointMake(0, -topCorrection);
}
@end
Solution 11 - Iphone
I have also this problem and I solved it with a UITableViewCell
with UITextView
. I created method in a custom UITableViewCell
subclass, property statusTextView
:
- (void)centerTextInTextView
{
CGFloat topCorrect = ([self.statusTextView bounds].size.height - [self.statusTextView contentSize].height * [self.statusTextView zoomScale])/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
self.statusTextView.contentOffset = (CGPoint){ .x = 0, .y = -topCorrect };
And call this method in methods:
- (void)textViewDidBeginEditing:(UITextView *)textView
- (void)textViewDidEndEditing:(UITextView *)textView
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
This solution worked for me with no issues, you can try it.
Solution 12 - Iphone
Swift 3:
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
textField.frame = self.view.bounds
var topCorrect : CGFloat = (self.view.frame.height / 2) - (textField.contentSize.height / 2)
topCorrect = topCorrect < 0.0 ? 0.0 : topCorrect
textField.contentInset = UIEdgeInsetsMake(topCorrect,0,0,0)
}
Solution 13 - Iphone
Add to Carlos answer, just in case you have text in tv bigger then tv size you don't need to recenter text, so change this code:
tv.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
to this:
if ([tv contentSize].height < [tv bounds].size.height) {
tv.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
}
Solution 14 - Iphone
Auto-layout solution:
- Create a UIView that acts as a container for the UITextView.
- Add the following constraints:
- TextView: Align leading space to: Container
- TextView: Align trailing space to: Container
- TextView: Align center Y to: Container
- TextView: Equal Height to: Container, Relation: ≤
Solution 15 - Iphone
You can try below code, no observer mandatorily required. observer throws error sometimes when view deallocates. You can keep this code in viewDidLoad, viewWillAppear or in viewDidAppear anywhere.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
dispatch_async(dispatch_get_main_queue(), ^(void) {
UITextView *tv = txtviewDesc;
CGFloat topCorrect = ([tv bounds].size.height - [tv contentSize].height * [tv zoomScale])/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
tv.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
});
});
Solution 16 - Iphone
I did it like this: first of all, I embedded the UITextView in an UIView (this should work for mac OS too). Then I pinned all four sides of the external UIView to the sides of its container, giving it a shape and size similar or equal to that of the UITextView. Thus I had a proper container for the UITextView. Then I pinned the left and right borders of the UITextView to the sides of the UIView, and gave the UITextView a height. Finally, I centered the UITextView vertically in the UIView. Bingo :) now the UITextView is vertically centered in the UIView, hence text inside the UITextView is vertically centered too.
Solution 17 - Iphone
UITextView+VerticalAlignment.h
// UITextView+VerticalAlignment.h
// (c) The Internet 2015
#import <UIKit/UIKit.h>
@interface UITextView (VerticalAlignment)
- (void)alignToVerticalCenter;
- (void)disableAlignment;
@end
UITextView+VerticalAlignment.m
#import "UITextView+VerticalAlignment.h"
@implementation UITextView (VerticalAlignment)
- (void)alignToVerticalCenter {
[self addObserver:self forKeyPath:@"contentSize" options:NSKeyValueObservingOptionNew context:NULL];
}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
UITextView *tv = object;
CGFloat topCorrect = ([tv bounds].size.height - [tv contentSize].height * [tv zoomScale])/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
tv.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
}
- (void)disableAlignment {
[self removeObserver:self forKeyPath:@"contentSize"];
}
@end
Solution 18 - Iphone
I fixed this problem by creating extension to center height vertically.
SWIFT 5:
extension UITextView {
func centerContentVertically() {
let fitSize = CGSize(width: bounds.width, height: CGFloat.greatestFiniteMagnitude)
let size = sizeThatFits(fitSize)
let heightOffset = (bounds.size.height - size.height * zoomScale) / 2
let positiveTopOffset = max(0, heightOffset)
contentOffset.y = -positiveTopOffset
}
}
Solution 19 - Iphone
Solution for iOS10 in RubyMotion:
class VerticallyCenteredTextView < UITextView
def init
super
end
def layoutSubviews
self.recenter
end
def recenter
contentSize = self.sizeThatFits(CGSizeMake(self.bounds.size.width, Float::MAX))
topCorrection = (self.bounds.size.height - contentSize.height * self.zoomScale) / 2.0;
topCorrection = 0 if topCorrection < 0
self.contentInset = UIEdgeInsetsMake(topCorrection, 0, 0, 0)
end
end