Develop Reference

Android Material Design Components Sample

I'm new at material design. I'm working on some projects and I want to use the material design. But I cannot find any source or sample for components. Is there any code sample (especially animated circle loader)?
Thanks a lot!

There are tens (if not hundreds) samples regarding ways to implement Material Design, some of 'em even described how you could make it work for older versions of Android.
This blog post by Google's own Chris Banes regarding AppCompat v21 is a good place to start when you're also working on Android versions lower than Lollipop.
While this, still from Mr. Banes, thoroughly describe one of Lollipop's most famed API, Palette.
Moving on, this blog post would help you started with those shiny round buttons (or FABs) and, as a bonus, a trick to apply ripple effect to it.
I think those three links should be more than enough to get you started making Material apps - I've built mine and those three were my first guides. Sadly though, I can't find one that matches exactly with your Dribbble link. Then again, I doubt a widget such as those exists today. I've been wrong before though. :)
Hope this helped!

Learn more:
Modular and customizable Material Design UI components for Android
Git link:
https://github.com/material-components/material-components-android
Playstore link:
https://play.google.com/store/apps/details?id=io.materialdesign.catalog

Android Bootstrap what is that really, what does it do?

According to this link www.androidbootstrap.com/‎ I am wondering what does it really do, what is for? Am I supposed to use it?
I've read all text on this main page but I am still confused and I do not know should I use it.
The main problem is I don't see the point. Could someone tell me what is it for?
I am open for new technologies but here is the example where I don't understand, but they say that using their package will shorten my work on application.
Regards and I am looking for any information.

I am wondering what does it really do
It generates a skeleton Android project containing specific libraries. It is reminiscent of the new-project wizard in Eclipse, just supporting more third-party libraries, particularly ones that may be a bit of a challenge to get working together.

I had a look at this project to provide a quick set up for actionbarsherlock and dagger DI.
I think it’s a good idea as it seeks to provide an android template, with an out the box solution including sherlock and dagger. But I couldn’t get it working on eclipse, and the forum had a lot of people saying the same (I think its designed for Intelij IDEA)
I also looked at androidkickstartr which is more mature, but again had import issues, so just made my own template and imported sherlock and dagger

Path-App like round menu in Android

today I came across the Path App:
And wanted to ask if its possible to implement this round menu in Android. Would be a Framelayout a good solution or what would be better? Also I heard hat somebody had crated a library which implemented almost the same thing. But didn't found anything.

Here are some open source projects that do it:
https://github.com/daCapricorn/ArcMenu - Apache 2.0
https://github.com/siyamed/android-satellite-menu/ - LGPL

XML for Android Programming

I just picked up the Android Apps for Absolute Beginners and I read the introduction, it turns out you have to know Java.... so I read Sam's Teach Yourself Java And 24 Hours and I thought I was ready to dive into Android programming. When I began reading the book I noticed there was a lot of XML stuff and I don't know XML.. my question is, how much XML do you have to know in order to write Android apps. Can someone recommend a book or resource that has information about XML and Android? I have about three years of Objective-C experience and a couple days of Java experience.
Thanks!

You don't need to know much about XML. Most of what you need can be absorbed by imitation. You don't need to know much more than the basics of XML syntax. (An easy XML tutorial can be found at W3Schools. An even briefer tutorial, as well as links to the W3Schools tutorial and other learning resources can be found at the XML Introduction page at the Mozilla Developer Network site.) As to concepts of how XML and Java work together in Android, I'd strongly recommend that you go through the training material on XML at the Android web site.

OK so there are a few questions in here that need breaking down...
"how much XML do you have to know in order to write Android apps"
You need to know the basics. XML is not a programming language (as I am sure you are aware) and is a markup language. If you have 3 years of C under your belt this will take you all of a day at most to get your head round if not less.
Read the W3 Schools guide to XML http://www.w3schools.com/xml/ it has everything you need.
"it turns out you have to know Java.... so I read Sam's Teach Yourself
Java And 24 Hours and I thought I was ready to dive into Android
programming"
Your existing knowledge should serve you well but spending 3 days on a language may simply not be enough (unless you are amazing in which case i retract this statement). Java in my own opinion is quite as nice language to learn and you should pick it up quite quickly with a little time.
Have you read the Android Developers documentation? Read it well, it has lots and lots of help. Every time I seem to write an answer or comment I reference the documentation. Have you checked the samples? I find learning by example/practically quite useful and far more engaging.

You should see and learn developer.android.com for android developers. In this website, you'll know about XML s very well and they're also sample to understand. You don't need to think about that. Check it out.

Please be aware that this answer is mostly focused on Android application development using Android Studio and may not be true for other development tools and methods.
XML is a markup language used for styling Android applications, it is generally used as a means of separating the application’s styling from the actual logic - meaning that that the “image” and “functionality” of the application are separate and if one changes, the other does not have to.
To develop an Android application, you don’t need to know XML, On Android's Developer website - it states that you can either style your application at runtime using Java or use XML. Though a basic understanding of XML may come in handy for problem-solving.
And even if you wish to use XML to style your app - you don't need /an in-depth knowledge of it as you can simply use Android Studio’s Layout-Editor (only versions 2.3 or higher can do this) - which will allow you to style your application visually and generate the corresponding XML afterwards which you're free to edit if you please.
Sources
https://developer.android.com/guide/topics/ui/declaring-layout.html
https://developer.android.com/training/basics/firstapp/building-ui.html#strings
Also see:
- TutorialsPoint's Android tutorial titled "Styles and Themes"
- W3Schools' XML tutorials.
- As well as any of the appealing links on Android's developer website, TutorialsPoint and off-course W3Schools websites.
Forgive me for any mistakes in this post and you're free to correct them, forgive me for my inability to provide all the relevant links (due to my low reputation) and I hope this helps at least someone.

Learning resources for Android Open Source Project (AOSP)

I can't find any good learning resource on AOSP. Can't find any books, or comperhensive web resources on that topic. Book that would cover all topics about it would be best. Like how to setup enviroment, download code, use repo/git, change basic things, make custom roms, etc etc. Is there any book like that? Or any other resource on web that have that info in one place?

Karim Yaghmour's embedded android covers a fair bit of AOSP stuff. There are some good videos by Tim Bird and Yaghmour, google for those.
If you want to create custom roms you probably want the xda-developers and their forums or cyanogen.
Repo docs are fairly sparse: see this post for that.

this could be a start : http://source.android.com/source/downloading.html

The resource that really introduced me in this topic is this. There are two videos that give basic knowledge about the AOSP development process. After that, the best your choice is Google :) But then you'll know what to answer!