Develop Reference

How to use TextClassificationManager to Detect language

TextClassificationManager is available from API-26. Its public methods available for classify text .
My requirement is i need to detect language from a giver Text offline.
TextClassificationManager also have detectLanguages() method but its hidden.
Can i Use TextClassificationManager to detect language ?
I have searched a bit and i Found This Project Using TextClassificationManager by Reflection. But it throws NoSuchMethodErrror and Returns ..
So if anyone Used TextClassificationManager for this purpose can help me .

It's a bad decision to use hidden functions via reflection. You can never know if the function will be there and available so you have to prepare a fallback mechanism.
For Android SDK 26-27 You can try and use this Android lib project - https://github.com/rmtheis/language-detection but be aware that it's no longer maintained so use it for your own research but it's probably not a good idea to use it for production or apps released in Google Play.

HERE SDK: Android PositioningManager.setDataSource(LocationDataSource) does not exist

I've followed the instructions for the tutorials for Android using HERE APIs.
PositioningManager.setDataSource(LocationDataSource) doesn't exist as described https://www.developer.here.com/documentation/android-premium/dev_guide/topics/advanced-positioning.html
The documentation needs to be updated or library import needs to be less confusing. I really do not know what's going on. How can I get positioning to work?

Could it be that you are using the Starter Version of SDK which does not have the DataSource feature ? I could see the setDataSource method is available in the HERE Premium SDK.
The setDataSource is intended if you want to provide any external GPS sources (other than mobile device's default) , simple positioning can be started just by calling PositioningManager.start(LocationMethod) (https://www.developer.here.com/documentation/android-premium/dev_guide/topics/map-positioning.html)

Creating custom keyboard with spelling for Android

I would like to create my keyboard with corrective and spelling for using in every application or website on my device. Please suggest me about how possible and reference of my project.

You have to create an InputMethodService and it will work on all apps.
There is a lot of explanation. But i will include some basic. let me know if you have any confusion.
Read this tutorial create an InputMethod and then go through the second one
And two great tutorial are this and openSource LatinIME

Spelling Checker Framework
The Android platform offers a spelling checker framework that lets you implement and access spell checking in your application. The framework is one of the Text Service APIs offered by the Android platform.
To use the framework in your app, you create a special type of Android service that generates a spelling checker session object. Based on text you provide, the session object returns spelling suggestions generated by the spelling checker.
you can see this link https://developer.android.com/guide/topics/text/spell-checker-framework.html

Android - Custom made spell checker

I'm wondering if its possible to create a custom spell checker that other apps will use when they request spell checking.
The setting is here: http://i.imgur.com/15Co3t3.jpg
On my current phone, there are 2, Htc's own spell checker and googles. This led me to wonder if its possible to create my own.
I understand it would never be as good as the existing ones, but for some situations, a fully custom spell checker could be useful.
Is it possible to do this?

Its a good idea to check these useful and well-designed spell checker libraries.
1) spell-check-android (link)
2) HelloSpellChecker (link)
3) AndroidHunspellService (link)
4) Spell Checker (link)
5) Android's Spelling Checker Framework (link)
If you are in a hurry, you can directly use them in your project (just remember to give proper credit) or you can see how these libraries have been developed. These samples can help you a lot learn and implement it yourself. Learn the best from all.

static UI analysis with my own grammar rules (want to make eclipse android visual UI guidelines checker)

I want to make eclipse plugin or standalone app that will help user to check if android xml layout files are according to android user interface guidelines (that I have added earlier from). User can also input his own guidelines into existed grammar rules. Also he can choose some UI guidelines patterns (ones that is created for his company or some existed ones). What's the best approach to develop this app? What's the easiest and fastest way? Which language/approach I should choose? Can you provide me if possible with some tutorials/books/examples for this? I have found that it could be done with JavaCC(but it's difficult,user should edit/create grammar rules). Also I have found some recommendations to do it with DSL(Domain specific languages), code generators but I don't know how to do this.
I am doing UI checker for my master thesis. It should enable general code analysis in next phases - for some other students (thesis) to continue with this project (tracking navigation, coding style,etc). I am doing part which checks xml files with my grammar rules(which can be added,edited by users) and shows visually in gui editor where is warning(font too big, colors not compatible, etc.). My checker would work for android, but other students will make it for ios and windows phone.Thank you in advance.

This tool already exists, it is called 'Lint' and already is built and executed automatically by the Android IDEs:
http://tools.android.com/tips/lint
The tool is designed to allow you to add your own custom rules and checks:
http://tools.android.com/tips/lint/writing-a-lint-check
There are other static analysis tools (PMD, FindBugs, etc) that can also be used with Eclipse already, that could also be extended for your purposes. I don't think you want to create your own plugin, but should extend the existing tools.