I am using TTTAttributedLabel to apply formatting to text, however it seems to crash because I am trying to apply formatting to a range which includes emoji. Example:
NSString *text = #"#user1234 🍺🍺 #hashtag"; // text.length reported as 22 by NSLog as each emoji is 2 chars in length
cell.textLabel.text = text;
int length = 8;
int start = 13;
NSRange *range = NSMakeRange(start, length);
if (!NSEqualRanges(range, NSMakeRange(NSNotFound, 0))) {
// apply formatting to TTTAttributedLabel
[cell.textLabel addLinkToURL:[NSURL URLWithString:[NSString stringWithFormat:#"someaction://hashtag/%#", [cell.textLabel.text substringWithRange:range]]] withRange:range];
}
Note: I am passed the NSRange values from an API, as well as the text string.
In the above I am attempting to apply formatting to #hashtag. Normally this works fine, but because I have emoji involved in the string, I believe the range identified is attempting to format the emoji, as they are actually UTF values, which in TTTAttributedLabel causes a crash (it actually hangs with no crash, but...)
Strangely, it works fine if there is 1 emoji, but breaks if there are 2.
Can anyone help me figure out what to do here?
The problem is that any Unicode character in your string with a Unicode value of \U10000 or higher will appears as two characters in NSString.
Since you want to format the hashtag, you should use more dynamic ways to obtain the start and length values. Use NSString rangeOfString to find the location of the # character. Use that results and the string's length to get the needed length.
NSString *text = #"#user1234 🍺🍺 #hashtag"; // text.length reported as 22 by NSLog as each emoji is 2 chars in length
cell.textLabel.text = text;
NSUInteger start = [text rangeOfString:#"#"];
if (start != NSNotFound) {
NSUInteger length = text.length - start;
NSRange *range = NSMakeRange(start, length);
// apply formatting to TTTAttributedLabel
[cell.textLabel addLinkToURL:[NSURL URLWithString:[NSString stringWithFormat:#"someaction://hashtag/%#", [cell.textLabel.text substringWithRange:range]]] withRange:range];
}
I assume this is from the Twitter API, and you are trying to use the entities dictionary they return. I have just been writing code to support handling those ranges along with NSString's version of the range of a string.
My approach was to "fix" the entities dictionary that Twitter return to cope with the extra characters. I can't share code, for various reasons, but this is what I did:
Make a deep mutable copy of the entities dictionary.
Loop through the entire range of the string, unichar by unichar, doing this:
Check if the unichar is in the surrogate pair range (0xd800 -> 0xdfff).
If it is a surrogate pair codepoint, then go through all the entries in the entities dictionary and shift the indices by 1 if they are greater than the current location in the string (in terms of unichars). Then increment the loop counter by 1 to skip the partner of this surrogate pair as it's been handled now.
If it's not a surrogate pair, do nothing.
Loop through all entities and check that none of them overrun the end of the string. They shouldn't, but just incase. I found some cases where Twitter returned duff data.
I hope that helps! I also hope that one day I can open source this code as I think it would be incredibly useful!
Related
I want to replace all standard iOS emoji from a UILable or UITextView with twitters open source twemoji.
I can't find any library or documentation to do this in iOS. Does anyone have a solution that does not involve me implementing this from scratch?
The solution needs to be efficient and work offline.
The question got me intrigued, and after a bit of searching on how it would be possible to replace all standard iOS emoji with a custom set, I noticed that even Twitter's own iOS app doesn't use Twemoji:
In the end, I came to the same conclusion as you:
I can't find any library or documentation to do this in iOS.
So, I created a framework in Swift for this exact purpose.
It does all the work for you, but if you want to implement your own solution, I'll describe below how to replace all standard emoji with Twemoji.
1. Document all characters that can be represented as emoji
There are 1126 base characters that have emoji representations, and over a thousand additional representations formed by sequences. Although most base characters are confined to six Unicode blocks, all but one of these blocks are mixed with non-emoji characters and/or unassigned code points. The remaining base characters outside these blocks are scattered across various other blocks.
My implementation simply declares the UTF-32 code points for these characters, as the value property of UnicodeScalar is exactly this.
2. Check whether a character is an emoji
In Swift, a String contains a collection of Character objects, each of which represent a single extended grapheme cluster. An extended grapheme cluster is a sequence of Unicode scalars that together represent one1 human-readable character, which is helpful since you can loop through the Characters of a string and handling them based on the UnicodeScalars they contain (rather than looping through the UTF-16 values of the string).
To identify whether a Character is an emoji, only the first UnicodeScalar is significant, so comparing this value to your table of emoji characters is enough. However, I'd also recommend checking if the Character contains a Variation Selector, and if it does, make sure that it's VS16 – otherwise the character shouldn't be presented as emoji.
Extracting the UnicodeScalars from a Character requires a tiny hack:
let c: Character = "A"
let scalars = String(c).unicodeScalars
3. Convert the code points into the correct format
Twemoji images are named according to their corresponding code points2, which makes sense. So, the next step is to convert the Character into a string equivalent to the image name:
let codePoint = String("🙃").unicodeScalars.first!.value // 128579
let imageName = String(codePoint, radix: 16) // "1f643"
Great, but this won't work for flags or keycaps, so we'll have to modify our code to take those into account:
let scalars = String("🇧🇪").unicodeScalars
let filtered = scalars.filter{ $0.value != 0xfe0f } // Remove VS16 from variants, including keycaps.
let mapped = filtered.map{ String($0.value, radix: 16) }
let imageName = mapped.joined(separator: "-") // "1f1e7-1f1ea"
4. Replace the emoji in the string
In order to replace the emoji in a given String, we'll need to use NSMutableAttributedString for storing the original string, and replace the emoji with NSTextAttachment objects containing the corresponding Twemoji image.
let originalString = "🙃"
let attributedString = NSMutableAttributedString(string: originalString)
for character in originalString.characters {
// Check if character is emoji, see section 2.
...
// Get the image name from the character, see section 3.
let imageName = ...
// Safely unwrapping to make sure the image exists.
if let image = UIImage(named: imageName) {
let attachment = NSTextAttachment()
attachment.image = image
// Create an attributed string from the attachment.
let twemoji = NSAttributedString(attachment: attachment)
// Get the range of the character in attributedString.
let range = attributedString.mutableString.range(of: String(character))
// Replace the emoji with the corresponding Twemoji.
attributedString.replaceCharacters(in: range, with: twemoji)
}
}
To display the resulting attributed string, just set it as the attributedText property of a UITextView/UILabel.
Note that the above method doesn't take into account zero-width joiners or modifier sequences, but I feel like this answer is already too long as it stands.
1. There is a quirk with the Character type that interprets a sequence of joined regional indicator symbols as one object, despite containing a theoretically unlimited amount of Unicode scalars. Try "🇩🇰🇫🇮🇮🇸🇳🇴🇸🇪".characters.count in a playground.
2. The naming pattern varies slightly when it comes to zero-width joiners and variation selectors, so it's easier to strip these out of the image names – see here.
Easiest thing to do:
1) Load the twemoji images into your project.
2) Create an NSDictionary that correlates the emoji codes supported by iOS with the paths to the respective twemoji images:
NSArray *iOSEmojis = #[#"iOSEmoji1",#"iOSEmoji2];
NSDictionary *twemojiPaths = [NSDictionary dictionaryWithObjects:#[#"Project/twemoji1.png",#"Project/twemoji2.png"] andKeys:#[#"iOSEmoji1","iOSEmoji2"]];
3) Code your app to search for emoji strings and display the twemojis where the regular emojis would go:
for (NSString *emoji in iOSEmojis)
{
NSString *twemojiPath = [twemojiPaths valueForKey:emoji];
// Find the position of the emoji string in the text
// and put an image view there.
NSRange range = [label.text rangeOfString:emoji];
NSString *prefix = [label.text substringToIndex:range.location];
CGSize prefixSize = [prefix sizeWithAttributes: #{NSFontAttributeName: [UIFont fontWithName:#"HelveticaNeue" size:14]}];
CGSize emojiSize = [label.text sizeWithAttributes: #{NSFontAttributeName: [UIFont fontWithName:#"HelveticaNeue" size:14]}];
CGRect imageViewFrame = CGRectMake(prefixSize.width,label.frame.size.height,emojiSize.width,label.frame.size.height);
imageViewFrame = [self.view convertRect:imageViewFrame fromView:label];
UIImageView *imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
imageView.image = [UIImage imageWithContentsOfFile:twemojiPath];
}
In Objective-C, I am attempting to set a limit of character length for a UILabel, but I could not find a way anywhere. For example, a line of text is entered into the UILabel, say 100, but if the maximum character length is set to 50, I just want it to cut off at 50 exactly and not even truncate. I just would like for it to cut off once it hits the limit.
I have tried this; but it didn't work:
NSString *string = my_uilabelText;
if ([string length] >74) {
string = [string substringToIndex:74];
}
Any insight or help would be greatly appreciated. Thank you
Based on your comment, what you actually implemented would work. You just have to ensure your syntax is correct.
Assuming your getting a string from a database:
NSString *string = stringFromDatabase;
//execute your conditional if statement
if (string.length > 50) { //meaning 51+
/* trim the string. Its important to note that substringToIndex returns a
new string containing the characters of the receiver up to, but not
including, the one at a given index. In other words, it goes up to 50,
but not 50, so that means we have to do desired number + 1.
Additionally, this method includes counting white-spaces */
string = [string substringToIndex:51];
}
Then we must set the labels text, this doesn't happen autonomously. So completely:
NSString *string = stringFromDatabase;
if (string.length > 50) {
string = [string substringToIndex:51];
}
self.someUILabel.text = string;
I think the way you are doing it is probably not user friendly. You're getting the string of a UILabel that already has text set and then resetting it. Instead, you should set the desired text to the UILabel before it is called by the delegate
in iOS Objetive-C I am trying to get the number typed by the user in a text field to set the upper bounder of a random number generation function in C.
- (IBAction)pushTheButton2:(id)sender {
u_int32_t upperBound = (u_int32_t) textField3.text;
textField4.text = [NSString stringWithFormat:#"%d", arc4random_uniform(upperBound)];
}
The output is a giant number that makes no sense. To test if function works, if I hardcode the actual upper bound in the arc4random_uniform function, such as arc4random_uniform(5), then it works!
I figured this could be some kind of literal conversion, so I tried to make this work with u_int32_t but still not outputting the right range.
Can someone help? Thanks
You are currently taking the memory reference pointer of the text and using that as the upper bound.
Try doing something like this instead...
NSInteger upperBound = [textfield.text intValue];
This will convert the string into an int that you can then use in the arc random function.
To parse string to integer you should do:
NSInteger upperBound = [textfield.text integerValue];
Short version
From the docs:
NSLineBreakByWordWrapping
Wrapping occurs at word boundaries, unless the word itself doesn’t fit on a single line.
What is the set of all word boundary characters?
Longer version
I have a set of UILabels, which contain text, sometimes including URLs. I need to know the exact location (frame, not range) of the URLs so that I can make them tappable. My math mostly works, but I had to build in a test for certain characters:
// This code only reached if the URL is longer than the available width
NSString *theText = // A string containing an HTTP/HTTPS URL
NSCharacterSet *breakChars = [NSCharacterSet characterSetWithCharactersInString:#"?-"];
NSString *charsInRemaininsSpace = // NSString with remaining text on this line
NSUInteger breakIndex = NSNotFound;
if (charsInRemaininsSpace)
breakIndex = [charsInRemaininsSpace rangeOfCharacterFromSet:breakChars
options:NSBackwardsSearch].location;
if (breakIndex != NSNotFound && breakIndex != theText.length-1) {
// There is a breakable char in the middle, so draw a URL through that, then break
// ...
} else {
// There is no breakable char (or it's at the end), so start this word on a new line
// ...
}
The characters in my NSCharacterSet are just ? and -, which I discovered NSLineBreakByWordWrapping breaks on. It does not break on some other characters I see in URLs like % and =. Is there a complete list of characters I should be breaking on?
I recommend using "not alphanumeric" as your test.
[[NSCharacterSet alphanumerCharacterSet] invertedSet]
That said, if you're doing a lot of this, you may want to consider using CTFramesetter to do your layout instead of UILabel. Then you can use CTRunGetImageBounds to calculate actual rects. You wouldn't have to calculate your word breaks, since CTFrame will already have done this for you (and it would be guaranteed to be the same algorithm).
I have an NSString with a charactercode like this: 0x1F514.
I want to take this NSString and add it to another NSString, but not with the literal value of it, but the icon hidden behind it. In this case an emoticon of a bell.
How can I easily convert this NSString to show the emoticon instead of the character code?
Something like this would do:
NSString *c = #"0x1F514";
unsigned intVal;
NSScanner *scanner = [NSScanner scannerWithString:c];
[scanner scanHexInt:&intVal];
NSString *str = nil;
if (intVal > 0xFFFF) {
unsigned remainder = intVal - 0x10000;
unsigned topTenBits = (remainder >> 10) & 0x3FF;
unsigned botTenBits = (remainder >> 0) & 0x3FF;
unichar hi = topTenBits + 0xD800;
unichar lo = botTenBits + 0xDC00;
unichar unicodeChars[2] = {hi, lo};
str = [NSString stringWithCharacters:unicodeChars length:2];
} else {
unichar lo = (unichar)(intVal & 0xFFFF);
str = [NSString stringWithCharacters:&lo length:1];
}
NSLog(#"str = %#", str);
The reason simply #"\u1f514" doesn't work is because those \u values cannot be outside the BMP, i.e. >0xFFFF, i.e. >16-bit.
So, what my code does is check for that scenario and does the relevant surrogate pair magic to make the right string.
Hopefully that is actually what you want and makes sense!
If your NSString contains this "bell" character, then it does. You just append strings the usual way, like with stringByAppendingString.
The drawing of a bell instead of something denoting an unknown character is a completely separate issue. Your best bet is to ensure you're not using CoreText for drawing this, as it's been reported elsewhere, and I've seen it myself at work, that various non-standard characters may not work when printed that way. They do work, however, when printed with UIKit (that should be standard UI components, UIKitAdditions, and so on).
If using CoreText, you might get a bit lucky if you disable some text properties for the string with this special character, or choose appropriate font (but I won't help you here; we decided to leave the issue as Won't fix).
Having said that, the last time I was dealing with those was in pre-iOS 6 days...
Summary: your problem is not appending strings, but how you draw them.