Develop Reference

Is there any ways to know which language user is typing in EditText ? or Restrict user to type in English only

Any one have idea of getting language of user, who is typing in the EditText.
What I Have Tried ?
Please do not suggest Google's com.google.mlkit , I have already tried but not working when user types fast.
I have also tried setting up android:digits="All Alfabets", It is not working when I long press and paste from the ClipBoard, It is allowing text from the other language.

This seems like a very complex problem! And one that limiting the allowed characters won't solve - many non-English languages use the same Latin character set as English, or use it for a romanised version of their written language. nihongo o kaite imasu is Japanese, but that would pass an alphabet check!
Even where other characters are used (e.g. accented versions) it's not unusual for people to just drop them and use the "standard English" characters when typing, especially if they're being informal - e.g. Spanish uses accents on question words like ¿qué?, but people might just not bother (and skip the ¿ too, or just say k if they're being really informal)
And then there's the fact that English does use accented characters - someone can be naïve or blasé, but you don't want your app to tell people they're "not typing in English" if they write those things.
I don't know anything about mlkit but if it's capable of detecting language to some decent degree, it really might be the way to go for such a complex human problem. I'd suggest that instead of trying to interfere with the user's typing, you just trigger a check when they're done which validates what they've entered. If it looks ok, you can enable a button or whatever - if not, show an error message and make them fix it themselves.
You could do that kind of thing with a TextWatcher (or the doAfterTextChanged extension function that comes with the ktx-core AndroidX library) - you'd probably want to start a delayed task so it happens a moment after they stop typing, and that you can interrupt if they start typing again
val languageCheck = Runnable {
// do your check here, enable buttons / show errors as a result
}
// set up the checker
textView.doAfterTextChanged {
// cancel an existing delayed task
textView.removeCallbacks(languageCheck)
// schedule a new one
textView.postDelayed(languageCheck, delayMillis)
}

Programming in Android Studio to able the user to give three numbers and save them

in android stuido I would like to code an activity, where the user can input numbers. For, example he types the number to the textfield, click 'OK' button, then the textfield gets clear, he types the second number, than the third, and after they give the third number the program goes to another activity and sayst thanks for the free number. I would like to save the three numbers for further use and have them in an ascending order. How should I do it?

I agree with Andrii, this is a very vague and general question. To get you pointed in the right direction though, you would want a layout with an number based-editText widget (for the user input). I would then add the button, and then implement OnClickListener for the button so that everytime the button is pressed, it calls a method you will define that will store the value in an array or list (which can be sorted), along with some kind of tracker to keep track of how many numbers have been entered - then clearing the editText field so that another number can be input; on the third number, the method calls the activity via intent or some other way saying "thanks for the free number".
This is all general and it is going to take quite a bit of work and API Guide/DeveloperDocs searching on the Android web site.

android preference settings range value

I am implementing a preference activity so I can let choices to the user about what my app can and can't do and to define a user profile so I can change the way I request data.
I have one part where I need to show places to the user (restaurant, stores, etc) so I would like to be able to have a "range widget".
Let's say :
1 = poor
2 = cheap
3 = average
4 = rich
I want the user being able to say I want only store between 1 and 3 so it would need to be a widget with a double "circle" allowing the user to create a range.
Any idea of something like this existing ? (I am pretty sure I already seen something like this in the past but I can't remember where)

Take a look at RangeBar. It sounds exactly like what you need

Scan string for characters and return bounded text

I am writing a dictionary-type app. I have a list of hash-mapped terms and definitions. The basic premise is that there is a list of words that you tap on to see the definitions.
I have this functionality up and running - I am now trying to put dynamic links between the definitions.
Example: say the user taps on an item in the list, "dog". The definition might pop up, saying "A small furry [animal], commonly kept as a pet. See also [cat].". The intention is that the user can click on the word [animal] or [cat] and go to the appropriate definition. I've already gone to the trouble of making sure that any links in definitions are bounded by square brackets, so it's just a case of scanning the pop-up string for text [surrounded by brackets] and providing a link to that definition.
Note that definitions can contain multiple links, whilst some don't contain any links.
I have access to the string before it is displayed, so I guess the best way to do this is to do the scanning and ready the links before the dialog box is displayed.
The question is, how would I go about scanning for text surrounded by square brackets, and returning the text contained within those brackets?
Ideally the actual dialog box that is displayed would be devoid of the square brackets, and I need to also figure out a way of putting hyperlinks into a dialog box's text, but I'll cross that bridge when I come to it.
I'm new to Java - I've come from MATLAB and am just about staying afloat, but this is a less common task than I've had to deal with so far!

You could probably do this with a regular expression; something like this:
([^[]*)(\[[^]]+\])
which describes two "match groups"; the first of which means any string of zero or more characters that aren't "[" and the second of which means any string starting with "[", containing one or more characters that aren't "]", and ending with "]".
Then you could scan through your input for matches to this pattern. The first match group is passed through unchanged, and the second match group gets converted to a link. When the pattern stops matching your input, take whatever's left over and transmit that unchanged as well.
You'll have to experiment a little; regular expressions typically take some debugging. If your link text can only contain alphanumerics and spaces, your pattern would look more like this:
([^[]*)(\[[\s\w]+\])
Also, you may find that regular expression matching under Android is too slow to be practical, in which case you'll have to use wasyl's suggestion.

Quite simple, I think... As the text is in brackets, you need to scan every letter. So the basic recipe would be :
in a while loop scan every character (let's say, while i < len(text))
If scanned character is [:
i++;
Add letter at index i to some temporary variable
while (character # i) != ']' append it to the temporary variable
store this temporary variable in a list of results.
Some tips:
If you use solution above, use StringBuilder to append text (as regular string is immutable)
You might also want (and it's better, I think) to store starting and ending positions of all square brackets first, and then use string.substring() on each pair to get the text inside. This way you'd first iterate definition to find brackets (maybe catch unmatched ones, for early error handling), then iterate pairs of indices...
As for links, maybe this will be of use: How can I get clickable hyperlinks in AlertDialog from a string resource?

Android TextViews. Is parametrization possible? Is binding to model possible?

I am new to both Android and Stack Overflow. I have started developing and Android App and I am wondering two things:
1) Is it possible to parametrize a TextView? Lets say I want to render a text message which states something like: "The user age is 38". Lets suppose that the user age is the result of an algorithm. Using some typical i18n framework I would write in my i18n file something like "The user age is {0}". Then at run time I would populate parameters accordingly. I haven't been able to figure out how to do this or similar approach in Android.
2) Let's suppose I have a complex object with many fields. Eg: PersonModel which has id, name, age, country, favorite video game, whatever. If I want to render all this information into a single layout in one of my activities the only way I have found is getting all needed TextViews by id and then populate them one by one through code.
I was wondering if there is some mapping / binding mechanism in which I can execute something like: render(myPerson, myView) and that automatically through reflection each of the model properties get mapped into each of the TextViews.
If someone has ever worked with SpringMVC, Im looking for something similar to their mechanism to map domain objects / models to views (e.g. spring:forms).
Thanks a lot in advanced for your help. Hope this is useful for somebody else =)
bye!

In answer to #1: You want String.format(). It'll let you do something like:
int age = 38;
String ageMessage = "The user age is %d";
myTextView.setText(String.format(ageMessage, age));
The two you'll use the most are %d for numbers and %s for strings. It uses printf format if you know it, if you don't there's a quicky tutorial in the Formatter docs.
For #2 I think you're doing it the best way there is (grab view hooks and fill them in manually). If you come across anything else I'd love to see it.