Develop Reference

Bar code Reader without installing Third party application

I am new to Android. Can anyone give an idea to read bar code and Qr code without installing third party application ( without using Zxing Library). Just using phone camera only.? I am looking for ur answers..

Zxing is the best. You can use it without installing the zxing app.
You can use Zxing.
It's a better customisable QR Scanning library. Something that can be easy to implement and have more control for the developer.
I found some links
Alternative to zxing QR reader library for Java/Android?
Better use this :https://github.com/LivotovLabs/zxscanlib
https://code.google.com/p/android-quick-response-code/
You can use it without installing application.
Just extent the CaptureActivity Class after adding zxing as library project.

Please check this library - https://github.com/embarkmobile/zxing-android-minimal. It offers a minimal ZXing setup to include directly into your app without need to download the barcode scanner app from the Google Play. It's easy to use and it's available as dependency for Gradle and Maven.

include Zxing library as jar for android without adding it as a library

I am trying to create a QR code scanner using zxing library in my android application, i am able to create project by making zxing application as a library and add to my application as library, but for this to happen we need the application to be installed zxing appication to be installed, is there any possibility to use the library as jar file and acess scanner intent without library.
Thanks & Regards.
Nagendra.

Use ZBar, it's so much simpler to use.
http://zbar.sourceforge.net/
BTW it also supports iOS

Previewing and Opening PDF Documents in Android SDK like IOS SDK

For PDF files ios platform has UIDocumentInteractionController controller and UIDocumentInteractionControllerDelegate to open PDF documents in another application like evernote, dropbox, google drive etc. Is there a way like this for android platform? I found a sample for IOS in here but could not find a sample for Android.
Thanks.

I strongly recomend you look at MuPDF. This is open source project so you are free to integrate mupdf with your project, as well modify and distribute it. Developer say that muPdf is small, fast, and yet complete. And it's completly true!
But integrate MuPDF with existing android project is not easy. Here a few useful links:
Official docs
also look here
how to use with existing android project
Hope it help you

Not used this but you can try it ..
https://github.com/JoanZapata/android-pdfview

What is a better and easy way to integrate QR code scanning in android application

I have read about zxing library but have no experience on that, also is this possible to use inbuilt or installed barcode reader in my application..
Any one having any experience on this please can guide me step by step.
lots of thanks

Yes, it's very easy. Here is how you integrate by Intent.

Change apk made with app inventor using Eclipse (SDK)

I made an application using App Inventor and now I want to add Admob advertising to it. I need to change manifest and some "activity".
How I could open apk in Eclipse to cahnge it? If someone added admob advertising to application made in app inventor?
Please, help

I think that this isn't possible, because an apk doesn't contain source files but compiled bytecode files. So if you would want to edit such a project in eclipse, you would have to obtain the sourcecode of your app, which isn't possible in App Inventor AFAIK.
If you want to have full control over your source code, you should consider learning to program natively on android.
If you are really interested in android development, check out the official Android Developer's Guide at
http://developer.android.com/guide/index.html .
A good tutorial can also be found at
http://www.vogella.de/articles/Android/article.html .