I've seen all the work you guys here at XDA developer do (and it's all really great).
And i'd really like to be able to develop stuff for android devices like you guys!
I know how to use Eclipse to develop apps and i've made a few apps already (no games or any real good stuff because i'm still learning right now).
But I want to be able to develop ROMs,kernels,...etc.U know!!
I've signed up for a java coarse at "New Horizons" training center and i'm gonna start in about a month.
But that won't teach me everything,it won't even teach me everything about application-creating
So,here I am,asking you guys (android developers):
How can I learn the stuff that you've learned?
What websites should I check out?
Where and how can I learn how to develop complete apps,games,Roms and kernels for any android smartphone?
In other words;Tell me how you learned all this stuff,and how can I learn it too?
Thank U!!!
Custom ROMS are not created from scratch.
Existing ROMs from the manufactors are taken appart, dissected, modified and packed again to be uploaded here.
The best way to start on that is just by taking apart existing ROMs and looking through the files.
Modifiy some, repack them and check if it still works.
Repeat said process .
If you want to go deeper read up about decompiling & recompiling apk files.
Modifying bak smali code.
For creating your own kernels, just use google, so much info about that. Its not an android only topic, but a linux topic and the internet has plenty of info on that.
Good luck on your journy .
The first thing you have to do is to understand the system. This means you have to understand Linux, the kernel, the datasystem(because Android is obvisiously based on Linux).
You have to be able to understand written code or program/code yourself.
The best way to code for android is to learn java.
Read this here: http://developer.android.com/guide/index.html
Ok,thanks for the information.
But let me tell you what I already know and understand:
Android is Linux,I know what linux is,I know everything about it and i'm already using GNU Fedora and Ubuntu (I have spent countless hours reading the "about Ubuntu" and "about GNU"),In Android or Linux everything is a file and everything in the system or the apps has a file .
Now I have some questions that I need you to answer first before adding anything else:
1-Is learning Java enough?don't I need to learn any other programing languages?And if I do,then what languages will I need to learn?
2-how can I learn to build or modify an android kernel (linux)?give me a good site or something?
3-how can i learn to decompile and recompile apks and roms?
4-What will I be needing to learn in order to buid a kernel?
5-What programing langusge is the android source code written in?I think it's java,am I right?
I hope you answer these questions before adding anymore information.
Thanks in advance,and I hope it's not any trouble)
1-No, you need to compile and modify kernels etc. therefore you need to program in C(I guess)
2- Well, buy books about Linux and Kernels etc. Its quite difficult to teach it. You gotta learn yourself.
3- Decompiling and recompiling is not an option. Its like stealing - Dont modify apks without permission. If you got permission then you modify apks with the SDK(Java).
Roms are often compiled in C(I think)
4 - Books and the will to learn.
5. Android Source Code is C(like Linux), Android Apps are Java.
Quinity said:
1-No, you need to compile and modify kernels etc. therefore you need to program in C#(I guess)
2- Well, buy books about Linux and Kernels etc. Its quite difficult to teach it. You gotta learn yourself.
3- Decompiling and recompiling is not an option. Its like stealing - Dont modify apks without permission. If you got permission then you modify apks with the SDK(Java).
Roms are often compiled in C#(I think)
4 - Books and the will to learn.
5. Android Source Code is C#(like Linux), Android Apps are Java.
Click to expand...
Click to collapse
Just making sure you mean c, not c# right??
Try visiting the android website. There is a tutorial on how to get started with android development.
There is a fee that you would need to pay per year in order for your application to appear on the android market where you will be able to sell your product.
Java will be advantageous when it comes to android programming and if you know J2ME that will be a bonus as well.
ps:Learn from examples, buy a good book for beginners: “Hello, Android” and “Beginning Android“.
(i’m not a developer)
Nilurun said:
There is a fee that you would need to pay per year in order for your application to appear on the android market where you will be able to sell your product.
Click to expand...
Click to collapse
I believe it is a one time fee when you sign up, not a yearly fee.
Ok,I'm already using the Android developer website,but the whole thing takes time to read all the guidelines and do tutorials and packages.
So all i'm asking here:
What programming languages do I need to learn in order to be able to understand the native android source code and develop everything starting from kernel down to apps,I already know that I need to learn Java for apps and thanks to "Quinity" I know I need to learn C to understand the native source code.
I can easily learn C at any professional training center.The questions now are:
1-how and where can I learn to edit the Linux kernel and decompile and recompile ROM and APK files?
2-why do I even need to learn Java ME (formerly J2ME)?
I understand that Java ME is the java environment originally running on small devices with limited processors and performance such as mobile phones and smart phones,but what is the use of it when it comes to the app development,or any Android development at all?
And thanks for all the replies.
One more thing,I have to make sure what the android source code written in.And Quick answers;PLEASE.
Is it C,or C#?
C
Check out the wikipedia article, which states at the beginning:
The Android open-source software stack consists of Java applications running on a Java-based, object-oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore[21] media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc.
Dark3n said:
C
Check out the wikipedia article, which states at the beginning:
The Android open-source software stack consists of Java applications running on a Java-based, object-oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore[21] media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc.
Click to expand...
Click to collapse
Thanks,the article really did help a lot.
So,now I need to learn Java SE (without question),but what about Java EE and Java ME,will they be useful in the app development process,will I need them?
And what If I can't learn C (it's extremely hard to find a training center that teaches C these days),will learning C++ or C# do me any good?
I know that the source code is written in C,but is it really a big difference between the three,If I learn C# or C++ will I still be able to do everything I need to do and fully understand the code?
note that i'm on a tight schedule for now and I need to learn only the stuff I can't do without.
speeed_demon47 said:
Thanks,the article really did help a lot.
So,now I need to learn Java SE (without question),but what about Java EE and Java ME,will they be useful in the app development process,will I need them?
And what If I can't learn C (it's extremely hard to find a training center that teaches C these days),will learning C++ or C# do me any good?
I know that the source code is written in C,but is it really a big difference between the three,If I learn C# or C++ will I still be able to do everything I need to do and fully understand the code?
note that i'm on a tight schedule for now and I need to learn only the stuff I can't do without.
Click to expand...
Click to collapse
I think you are missunderstanding something here.
You should start by just learning java, the different EE ME SE etc. are still java.
The difference is that those are sets of java platforms. They bring, as does the android platform, prebuild libaries along, these contain functions (i.e. print that, create datastructure X) so you don't have to write every tiny bit of code.
Forget about those.
You want to use java on the android platform, which still uses java, but brings along its own libaries with prebuild code you can use ( See http://developer.android.com/reference/packages.html ).
So just learn java, if you want to work with android you can learn java on the android platform, this way you will already be familiar with the libaries provided by android.
I would say C# is more similar to java and C++ is more similar to C.
I don't understand what you mean with "do everything i need to do".
What do you need to do?
"Understand code".
Understanding code does require more than knowing what each line does, you will have to see the bigger picture ,not just few lines of code, to understand what is does. Depending on how the code is written (tidy or confusing), is the code commented? It might take ages to understand it.
Programming is sometimes a bit like art . Code can be beautiful or horrible
You don't have to do everything in a training center either.
The internet, time and interest is enough. There are so many tutorials and pages available...
You could have also found most of the answers by just using google...
Wikipedia article about java holds the information about the differences between EE/ME/SE etc...
Searching for terms like "difference C C sharp" etc. holds the answer to that question...
So maybe a training center is better for you to learn those programming languages, as "google skills" will certainly be required to teach you those things yourself.
What tight schedule are you on?
Dark3n said:
I think you are missunderstanding something here.
You should start by just learning java, the different EE ME SE etc. are still java.
The difference is that those are sets of java platforms. They bring, as does the android platform, prebuild libaries along, these contain functions (i.e. print that, create datastructure X) so you don't have to write every tiny bit of code.
Forget about those.
You want to use java on the android platform, which still uses java, but brings along its own libaries with prebuild code you can use ( See http://developer.android.com/reference/packages.html ).
So just learn java, if you want to work with android you can learn java on the android platform, this way you will already be familiar with the libaries provided by android.
I would say C# is more similar to java and C++ is more similar to C.
I don't understand what you mean with "do everything i need to do".
What do you need to do?
"Understand code".
Understanding code does require more than knowing what each line does, you will have to see the bigger picture ,not just few lines of code, to understand what is does. Depending on how the code is written (tidy or confusing), is the code commented? It might take ages to understand it.
Programming is sometimes a bit like art . Code can be beautiful or horrible
You don't have to do everything in a training center either.
The internet, time and interest is enough. There are so many tutorials and pages available...
You could have also found most of the answers by just using google...
Wikipedia article about java holds the information about the differences between EE/ME/SE etc...
Searching for terms like "difference C C sharp" etc. holds the answer to that question...
So maybe a training center is better for you to learn those programming languages, as "google skills" will certainly be required to teach you those things yourself.
What tight schedule are you on?
Click to expand...
Click to collapse
Yes,I already know all about java,I read the articles on wikipedia,but why would I need to learn java enterprise? Isn't it mostly used around internet applications and servers? Can't I just use the APIs if i'm going to build an app that needs internet or server connectivity?
And why would I need to learn java Micro? Doesn't android use dalvik virtual machine to run apps? I mean,java Micro is mostly used to create feature phone apps,why would I need it with android?
There's something I don't understand though,on wikipedia the article about android says this:"Applications are usually developed in the Java language using the Android Software Development Kit, but other development tools are available, including a Native Development Kit for applications or extensions in C or C++"
So,the question is;what is the difference between apps developed in java and apps developed in C or C++?
The problem about C# is that I don't know anything about it;can't find any articles on wikipedia and other sites really don't help!!!
I meant by "understanding the code",having the ability to understand the command lines,what they do,what each line is responsible for and having the ability to edit or adjust something,.....etc.
And for the tight schedule;I need to learn everything about android within 6 months (I don't need to learn C as much,but it'd be a bonus),and that's why I go to training centers,faster and more efficient than self learning.
What did u mean by "google skills"?
And what did u mean by "learn java on the android platform"?
Thanks for the help and providing quick answers.
speeed_demon47 said:
Yes,I already know all about java,I read the articles on wikipedia,but why would I need to learn java enterprise? Isn't it mostly used around internet applications and servers? Can't I just use the APIs if i'm going to build an app that needs internet or server connectivity?
And why would I need to learn java Micro? Doesn't android use dalvik virtual machine to run apps? I mean,java Micro is mostly used to create feature phone apps,why would I need it with android?
There's something I don't understand though,on wikipedia the article about android says this:"Applications are usually developed in the Java language using the Android Software Development Kit, but other development tools are available, including a Native Development Kit for applications or extensions in C or C++"
So,the question is;what is the difference between apps developed in java and apps developed in C or C++?
The problem about C# is that I don't know anything about it;can't find any articles on wikipedia and other sites really don't help!!!
I meant by "understanding the code",having the ability to understand the command lines,what they do,what each line is responsible for and having the ability to edit or adjust something,.....etc.
And for the tight schedule;I need to learn everything about android within 6 months (I don't need to learn C as much,but it'd be a bonus),and that's why I go to training centers,faster and more efficient than self learning.
What did u mean by "google skills"?
And what did u mean by "learn java on the android platform"?
Thanks for the help and providing quick answers.
Click to expand...
Click to collapse
You miss understood again...
I will try to be clearer:
I meant by google skills, that you would find most answer yourself if you just use a search engine with the right terms.
You DONT need to learn Java ME/SE etc.
You can and will only use the APIs provided by the android toolkit.
So if you already know java, google "android developement tutorial" and start build some apps to get experience.
Forget C#, you don't need that, AT ALL for android.
Android apps, only need java.
If you want to understand the deeper layers of android, those are written in C.
But "int i=0;" is a variable i with value 0 in java and in C. So if you just want to read some of the code of the deeper layers and change small bits, you don't need to take extra courses in C.
So the conclusion is, you need to understand the android architecture and be able to write apps and have experience...
I would recommend to just think of some thing and write an app for that, learning by doing. Occasionally you can read some theory about the underlying concept of what you are doing.
An example would be to write an app that sorts values the user enters.
You would use already premade sort and array functions from the android api
Something like
Code:
Array x;
x.addAll(y);
x.sort(Descending);
To get deeper knowledge you could then browse the android sourcecode and see how x.sort actually sorts the array.
I think Android application is writen in Java ?
But maybe it is not that your question?
Dark3n said:
You miss understood again...
I will try to be clearer:
I meant by google skills, that you would find most answer yourself if you just use a search engine with the right terms.
You DONT need to learn Java ME/SE etc.
You can and will only use the APIs provided by the android toolkit.
So if you already know java, google "android developement tutorial" and start build some apps to get experience.
Forget C#, you don't need that, AT ALL for android.
Android apps, only need java.
If you want to understand the deeper layers of android, those are written in C.
But "int i=0;" is a variable i with value 0 in java and in C. So if you just want to read some of the code of the deeper layers and change small bits, you don't need to take extra courses in C.
So the conclusion is, you need to understand the android architecture and be able to write apps and have experience...
I would recommend to just think of some thing and write an app for that, learning by doing. Occasionally you can read some theory about the underlying concept of what you are doing.
An example would be to write an app that sorts values the user enters.
You would use already premade sort and array functions from the android api
Something like
Code:
Array x;
x.addAll(y);
x.sort(Descending);
To get deeper knowledge you could then browse the android sourcecode and see how x.sort actually sorts the array.
Click to expand...
Click to collapse
Ok,good,thanks.
So,I don't need EE or ME,right? But if I learn them later on (maybe next year or so),would they come in handy or would they be useless?
I've been developing in Eclipse and SDK with ADT plugin,it's very helpful and I've completed most of the tutorials so far (hello world,tom cat,......etc) and started building something of my own.I've been also using Titanium app accelerator,it's really good too (still mainly eclipse but the tutorials and help are better);but so far all i've done is just copy the code and that's all,I didn't write a single line of code (maybe a few lines,but that's it).
I also started a course a week ago (learning Linux kernel),so far so good,And I found a good site to teach me image files.
But a little hung up on the programming languages section,so,conclusion;I need to learn Java Standard,would enterprise or micro be any good?
And about the native source code,will java be enough? won't I need to learn C?
Thanks for the quick responses,it's a lot of help.
HuTcHx said:
I think Android application is writen in Java ?
But maybe it is not that your question?
Click to expand...
Click to collapse
I already know that,but that's not what i'm asking about.
The enterprise edition and what not just offer different sets of libary for other platforms, aslong as long as you program for android devices you will have little use for knowledge of the other editions.
Think of it as being a specialised technican for cars. They all have engines and 4 tires and a steering wheel and all technicans can work with that, but will you work in a VW repair shop or in the Mercedes repair shop?
In this case you will work on the android platform, as long as you don't want to switch to server programming in java (Java EE) or embedded systems (Java ME), there is no need to get familiar with that.
Java SE means standart edition and basicly already included in the android libaries.
If you don't want to keep copy pasting code, try something different that has not been done in a tutorial, or modifiy a tutorial to do something else.
But there is nothing wrong with copying code, if you have written a good piece of code there is no harm in reusing it elsewhere.
The android sourcecode is a mix of java and C, the lower layers are written in C the higher ones in java.
I don't know what you want to achieve with your knowledge? To write apps you don't need to learn C.
It is difficult to master all fields, easier if you choose one.
Dark3n said:
The enterprise edition and what not just offer different sets of libary for other platforms, aslong as long as you program for android devices you will have little use for knowledge of the other editions.
Think of it as being a specialised technican for cars. They all have engines and 4 tires and a steering wheel and all technicans can work with that, but will you work in a VW repair shop or in the Mercedes repair shop?
In this case you will work on the android platform, as long as you don't want to switch to server programming in java (Java EE) or embedded systems (Java ME), there is no need to get familiar with that.
Java SE means standart edition and basicly already included in the android libaries.
If you don't want to keep copy pasting code, try something different that has not been done in a tutorial, or modifiy a tutorial to do something else.
But there is nothing wrong with copying code, if you have written a good piece of code there is no harm in reusing it elsewhere.
The android sourcecode is a mix of java and C, the lower layers are written in C the higher ones in java.
I don't know what you want to achieve with your knowledge? To write apps you don't need to learn C.
It is difficult to master all fields, easier if you choose one.
Click to expand...
Click to collapse
So,learning java enterprise isn't really important;but is it important if I want to excel in the development process?
But what's the use of learning Micro edition AT ALL when it comes to android development???
Isn't it used to develop apps for feature phones and PDAs,not smartphones?
And after I learn Java standard will I need to learn any special libraries for android? I mean,will I be able to get to writing the code right away or do I need to learn about the android files and libraries? or are they java standard already? I know I need to learn to compile the packages,but is that it?
And what about XML files,I can do them with JDK or Apache Ant,right? so,I don't need to worry about them,do I?
I'm trying to learn as much I can from the dev guide and the tutorials on the developers site,but the dev guide is too long to both read and comprehend,and that's basically a huge problem,cuz I have a job and education and I can't find time to know everything in the dev guide.
I know it'll be difficult to master all fields,but the team I'm going to work with needs someone who's able to edit the deeper layers of the code and,so I think I'll need both java and C for that job,it don't matter anyways I have time to learn both.
I am a programmer who has programmed in x86 Assembler, Visual C++ under Windows and DOS.
I need to be able to do own applications for Android KitKat 4.4.4
I need any help and information such as manuals, books, lists of commands, lists of functions, C compiler or, best, Assembler compilers for a given processor, etcetera.
I would like to code in Assembler. I guess I need an Assembler for a given processor and cell phone. In case not possible, I need a C compiler for Android 4.4.4 KitKat. I need the basic rules on how to code for this OS as well as the OS calls which I can use, as well as a description of function libraries which may come with the C compiler.
I prefer pure C than C++ or Java.
I have briefly searched the Internet with various key words and I have not been able to find anything relevant.
Please, does anyone have any information where I can get anything helpful.
I am totally new to this OS and I do not even know the shell commands. I do not have much information of the shell, although I have found a basic list on this forum and I use ls and ? and go by the name as a dumb fool.
Please, advise.
While Android is in Java, it also allows you to run C/C++ native code.
Search "Android NDK" and you will find the relevant documentation.
Arws Apps said:
While Android is in Java, it also allows you to run C/C++ native code.
Search "Android NDK" and you will find the relevant documentation.
Click to expand...
Click to collapse
Thanks. I have tried NDK. I am not sure whether I have installed this correctly but I would keep this.
Because NDK is hardware specific and I am not sure whether and how much Moto E XT1023 and others are supported, I have installed Android Studio 1.2 ad started with XML and Java. I have done similar things with HTML and Java for web sites. I would use XML as much as I can and Java only to get and set some variables, then I would use C for programming and then I would set Java variables and methods. I am not very happy with Java but there is not any other way for now. Hopefully, in the future, they would make XML a real language with all the resources available, functions and methods.
At least Java has a very C-like syntax, so in general it shouldn't be that difficult. In some sense it would even be easier (no memory management).
Arws Apps said:
At least Java has a very C-like syntax, so in general it shouldn't be that difficult. In some sense it would even be easier (no memory management).
Click to expand...
Click to collapse
Yes. You are right. I would prefer, however, a pure ANSI C. This can be done either as an interpreter to be hardware independent or as a compiler upon launch, the system would have a compiler, the user would download only the ASCI text. Upon launch, the compiler would be called first to compile and then the application can be launched. Then, the user can either keep the .exe or keep just the ASCI text, in which case, new compilation has to be done with every launch. A compilation would normally take one or a few seconds only for normal applications.