remove

Detect and remove Emojis from Text on Windows Phone

noemoticonskeyboard

In my recent project, I work with a lot of text that get’s its value from user input. To enable the best possible experience for my users, I choose the InputScope Text on all TextBoxes, because it provides the word suggestions while writing.

The Text will be submitted to a webserver via a REST API. And now the problem starts. The emojis that are part of the Windows Phone OS are not supported by the API and the webserver.

Of course, I was immediately looking for a way to get around this. I thought this might be helpful for some of you, so I am sharing two little helper methods for detecting and removing the emojis .

After publishing the first version of this post, I got some feedback that made me investigating a bit more on this topic.  The emojis are so called unicode symbols, and thanks to the Unicode behind it, they are compatible with all platforms that have the matching Unicode list implemented.

Windows Phone has  a subset of all available Unicode characters in the OS keyboard, coming from different ranges in the Unicode characters charts. Like we have to do sometimes, we have to maintain our own list to make sure that all emojis are covered by our app in this case and update our code if needed.

If you want to learn more about unicode charts, they are officially available here: http://www.unicode.org/charts/

Update 2: I am using this methods in a real world app. Although the underlying Unicode can be used, often normal text will be read as emoji. That’s why I reverted back to my initial version with the emojis in it. I never had any problems with that.

Now let’s have a look at the code I am using. First is my detecting method, that returns a bool after checking the text (input):

             public static bool HasUnsoppertedCharacter(string text)
             {
            string pattern = @"[{allemojisshere}]";

            Regex RegexEmojisKeyboard = new Regex(pattern);

            bool booleanreturnvalue = false;

            if (RegexEmojisKeyboard.IsMatch(text))
            {
                booleanreturnvalue = true;
            }
            else if (!RegexEmojisKeyboard.IsMatch(text))
            {
                booleanreturnvalue = false;
            }
            return booleanreturnvalue;
            }

 

As you can see, I declared a character range with all emojis. If one or more emojis is found, the bool will always return true. This can be used to display a MessageBox for example while the user is typing.

The second method removes the emojis from any text that is passed as input string.

             public static string RemovedUnSoppertedCharacterString(string text)
             {
            string result = string.Empty;
            string cleanedResult = string.Empty;

            string pattern = @"[{allemojishere}]";

            MatchCollection matches = Regex.Matches(text, pattern);

            foreach (Match match in matches)
            {
                result = Regex.Replace(text, pattern, string.Empty);
                cleanedResult = Regex.Replace(result, "  ", " ");
            }
            return cleanedResult;
             }

Also here I am using the character range with all emojis . The method writes all occurrences of emojis into a MatchCollection for Regex. I iterate trough this collection to remove all of them. The Method also checks the string for double spaces in the text and makes it a single space, as this happens while removing the emojis .

User Experience hint:

use this method with care, as it could be seen as a data loss from your users. I am using the first method to display a MessageBox to the user that emojis are not supported and that they will be removed, which I am doing with the second method. This way, my users are informed and they don’t need to do anything to correct that.

You might have noticed that there is a placeholder “{allemojishere}” in the code above. WordPress or the code plugin I use aren’t supporting the Emoticons in code, that’s why I attached my helper class.

As always, I hope this will be helpful for some of you.

Happy coding!

Posted by msicc in Dev Stories, windev, 1 comment

A simple approach to remove QueryStrings from NavigationContext on Windows Phone

QuerystringsRemove

Like most of you know, I am currently adding a lot of new features to my NFC Toolkit for Windows Phone.

Today, my coding session is all about uri schemes again. I successfully added some new uri schemes that you will be able to use soon.

However, if you start an app via an uri scheme, you will have  QueryStrings in your NavigationContext on the desired ApplicationPage. If a user continues to use your app, navigates away from the launched page and back to it, the code based on your QueryStrings will be called again.

As I am a daily Windows Phone user by myself, I know this is somewhat annoying. So I searched for a solution. I first thought about removing entries in the BackStack, but that would need a lot of code if you are running an application that has more than two pages – you’ll need to add methods to check if you are coming from an uri scheme, clear the BackStack, pass the parameters to the next page, get back to your MainPage, check the parameters again. Totally unusable in my opinion.

The NavigationContext.QueryString property has a Remove() method as I found out while researching a bit more – that’s what I am using now to get the result I want – make the app running like it was launched normally without uri scheme after the action has taken place.

I found some examples that are using the method in the  OnNavigatedTo() event. I don’t think that’s the right way, as I often happen to have some more code in this event, and it will probably break other functionality. I am using the OnNavigatedFrom() event.

Add this lines of code for every QueryString you want to remove (depending on your method structure, it is ok to remove only the QueryString you rely on in your further code, additional parameters can be still there ):

protected override void OnNavigatedFrom(NavigationEventArgs e)
{
   if (NavigationContext.QueryString.ContainsKey("key1"))
   {
      NavigationContext.QueryString.Remove("key1");                                
   }
   if (NavigationContext.QueryString.ContainsKey("key2"))
   {
       NavigationContext.QueryString.Remove("key2");
   }            
   base.OnNavigatedFrom(e);
}

This way, if you are navigating to another page in your app or even if the user uses the Windows Button, the corresponding QueryString will be removed – and your users are able to use the app as they would have launch it without an uri scheme.

However, that’s not all. When your app get’s Tombstoned, the UriMapper will map the uri scheme again on Activation – not what you might want. To get around this, I use a simple Boolean, set it to true when I am coming back from Tombstoning:

private void Application_Activated(object sender, ActivatedEventArgs e)
{
    if (!e.IsApplicationInstancePreserved)
    {
        wasTombstoned = true;  
    }
}

Now the only thing you will need to to is to add

&& App.wasTombstoned == false

as second argument to your QueryString clause – that’s it!

I am not sure if this is a good approach or not, but it works. It allows you to launch your uri scheme, and enables the user to use your app after that as it would have been launched normally. If you have other ways to get the same result, feel free to leave a comment below.

Otherwise, I hope this post is helpful for some of you.

Happy coding!

Posted by msicc in Dev Stories, windev, 5 comments