How to calculate TextView height base on text - ios

Question

I am using the code below for calculate the height of text, then set this height for UILabel and UITextView
CGSize targetSize = CGSizeMake(300, CGFLOAT_MAX);
NSString *message = #"The Internet connection appears to be offline.";
NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
CGSize boundingBox = [message boundingRectWithSize:targetSize
options:NSStringDrawingUsesLineFragmentOrigin
attributes:#{NSFontAttributeName:FontOpenSanWithSize(14)}
context:context].size;
CGSize size = CGSizeMake(ceil(boundingBox.width), ceil(boundingBox.height));
// it will return size:width = 299 and size height 20
// => if I use this height and set for UILabel, it can display full content
// => if I use this height and set for UITextView, it can not display full content
It's work perfect for UILabel but for UITextView sometime it calculate wrong.
I think the problem happened because the padding (left, right) of UITextView is bigger than UILabel.
So how can I calculate the correct size of text for display in UITextView. Any help or suggestion would be great appreciated.
Like the description image below
With the same size (300), same font, same text but the UITextView display in 2 lines, but UILabel in 1 lines.
And my code for calculate height return 20, it not enough for display in 2 lines, so the UITextViewcan not display full content
The reason why I need to calculate the height of UITextView base on text because my UITextView is in a popup.
And the popup height will depend on the TextView height

Answer 1

There are two things you can try:
Set textView.textContainerInset = UIEdgeInsetsZero
Set textView.textContainer.lineFragmentPadding = 0
With these operations you can get rid of all the padding in the textView and when its width matches with the label's one the heights are also the same.
Here's a sample code you can place in an empty viewController and test it yourself:
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
NSString *text = #"The internet connection appears to be offline.";
CGFloat width = 100.f;
UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(20, 20, width, 300)];
textView.font = [UIFont fontWithName:#"AvenirNext-Regular" size:12.f];
textView.text = text;
[self.view addSubview:textView];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(20 + width, 20, width, 300)];
label.numberOfLines = 0;
label.font = [UIFont fontWithName:#"AvenirNext-Regular" size:12.f];
label.text = text;
[self.view addSubview:label];
// Getting rid of textView's padding
textView.textContainerInset = UIEdgeInsetsZero;
textView.textContainer.lineFragmentPadding = 0;
// Setting height of textView to its contentSize.height
CGRect textViewFrame = textView.frame;
textViewFrame.size = textView.contentSize;
textView.frame = textViewFrame;
// Setting height of label accorting to it contents and width
CGRect labelFrame = label.frame;
labelFrame.size = [label sizeThatFits:CGSizeMake(width, HUGE_VALF)];
labelFrame.size.width = width;
label.frame = labelFrame;
NSLog(#"Label bounds: %#", NSStringFromCGRect(label.bounds));
NSLog(#"TextView bounds: %#", NSStringFromCGRect(textView.bounds));
// Visualizing final effect with borders
textView.layer.borderColor = [UIColor redColor].CGColor;
textView.layer.borderWidth = 1.f;
label.layer.borderColor = [UIColor greenColor].CGColor;
label.layer.borderWidth = 1.f;
}
Console output:
2016-09-01 14:29:06.118 stack39268477[943:243243] Label bounds: {{0, 0}, {100, 66}}
2016-09-01 14:29:06.119 stack39268477[943:243243] TextView bounds: {{0, 0}, {100, 66}}

Answer 2

You don't need to calculate Height of UITextview based on text.
Just change frame and set height like this:
textview.size.height = textview.contentSize.height;
This is easy solution. I hope this helps you.

Answer 3

This calculates the size of any string, whether or not you put them in a text view.
let frame = NSString(string: yourText).boundingRect(
with: CGSize(width: yourDesiredWidth, height: .infinity),
options: [.usesFontLeading, .usesLineFragmentOrigin],
attributes: [.font : yourFont],
context: nil)
let height = frame.size.height

Answer 4

Most of the answers here are hints into the right direction :-)
So, just to sum it all up...
UITextView uses a NSTextContainer (inside a private API _UITextContainerView) to do the real layout work.
This NSTextContainer(View) may have insets to the surrounding UITextView, which are set by UITextView's textContainerInset property.
The defaults for this insets seem to be:
top: 8
left: 0
bottom: 8
right: 0
The NSTextContainer itself may have additional left and right insets for the text itself. These insets are set in NSTextContainer's lineFragmentPadding property.
The default for this is 5.0.
As a result, when calculating the optimum frame size for a UITextView based on the boundingRect for some text inside that UITextView, we have to take all these insets into account:
CGSize reservedSpace = CGSizeMake((textView.textContainerInset.left + (2.0 * textView.textContainer.lineFragmentPadding) + textView.textContainerInset.right),
(textView.textContainerInset.top + textView.textContainerInset.bottom));
CGSize targetSize = CGSizeMake((300.0 - reservedSpace.width), CGFLOAT_MAX);
NSString* message = #"The Internet connection appears to be offline.";
NSStringDrawingContext* context = [[NSStringDrawingContext alloc] init];
CGSize boundingBox = [message boundingRectWithSize:targetSize
options:NSStringDrawingUsesLineFragmentOrigin
attributes:#{NSFontAttributeName:FontOpenSanWithSize(14)}
context:context].size;
CGSize size = CGSizeMake(ceil(boundingBox.width),
(ceil(boundingBox.height) + reservedSpace.height));
Good luck :-)

Answer 5

Swift 5
A classic hack I've used to do this is create a function that takes the String as a parameter. Within the function it generates a label with the width required, infinite number of lines, and a height of "too much". Then apply sizeToFit() on the label and return the height of the frame.
func calculatedHeight(for text: String, width: CGFloat) -> CGFloat {
let label = UILabel(frame: CGRect(x: 0, y: 0, width: width,
height: .greatestFiniteMagnitude))
label.numberOfLines = 0
label.text = text
label.sizeToFit()
return label.frame.height
}
The returned height can be applied to a UITextField height anchor. Though I do recommend calculating the width dynamically based on screen size, but that's up to you.

Answer 6

self.textView.textContainerInset = UIEdgeInsets.zero
self.textView.textContainer.lineFragmentPadding = 0
In storyboard or xib mark textview height >=0.
If you are using text view with table view.
Calculate cell height according to content, textview will adjust it's space.