Gadgetory

hello there my name is Gary Sims from Android authority now I'm sure you know that Android is an open source project that means all the source code is available on the Internet and you can download it and build your own based version of Android now this means that there are plenty of private individuals hobbyist groups and even commercial enterprises that use the open-source code for Android to build their own Android variation if you think about signage and model sides and ink they are probably the two most famous examples now have you ever wondered how to download and build Android make some modifications and therefore produce your own customized version of Android well let me explain everyone we get any grand visions of producing the next version of Sandwich in modern we're going to just modify Android so much let's just have a reality check here Android is a complicated and full operating system and there is lots and lots of components to it there's all with the lips kernel and there are all the frameworks and subsystems and different stacks that need to do all the stuff that Android can do then there's the user interface on top of that and there's the core applications on top of that I mean it's big I mean the build space on my build machine is 120 gigs so that just shows you how much data there is involved in building a vote about not all source code by any means but it's a huge amount of data so what we're going to do today is do some very very simple things just pitting step baby steps really just to see the principles involved in building and modifying androids ah you get your own custom distribution now what we're going to do is two things first of all we're going to download and build the Android source code using the Android Open Source project and then once we have that successfully flashed onto a test device we are going to modify some things about it and then flash that modifications onto the test device to see a variation of Android that we've done using our own fingers now before we get started we must say there are some prerequisites to this now what are the prerequisites you need to have some command line knowledge with let's on Linux with us on Mac OS 10 you really do need to have some command line knowledge and that includes also not only things like CD and LS and change directory and all that kind of stuff but also things like make and Java compilers and just editing source code from the command line if you don't have that kind of knowledge then really you're going to find this a bit of a struggle but you have that knowledge if you know what I make file is if you know what a compiler is then this is going to be fairly straightforward now Google have got some great documentation on the Android Open Source project website about how you download and build the Android Open Source project now I'm not going to repeat in verbatim all the things they've said there so a couple of bits of advice first of all go and read that documentation the link is here in the description it's also over on the Android chrome website with the article that goes along with this video read it then we in again and then when you think you've read it again read it a third time because if you skip over bits if you don't register things and it's said if you didn't understand something you said it's going to make the whole build process difficult but if you've absorbed all of those build instructions if you understand the principles are going on you can be a whole lot easier for you now the basic steps to building the Android Open Source project are like this first of all you need to have a compatible build environment and that means basically a Linux machine or a Mac os10 machine now you're going to need quite a bit of memory in hard disk space my Mac has got eight gigs of memory and 120 gigabytes of disk space was put aside for this build so you're going to need those kind of requirements to be able to download and start the build process now once you establish the build environment the next step is to sync your local repository with the repository without on the incident and that's pretty huge for me it took 24 hours so it's the kind of thing you're going to run overnight and maybe a bit longer and you're going to see the results slowly but it is working don't worry it is working it just takes a long long time now once you've got the source code once you've got the build environment established you need to get hold of the binaries now not all the drivers for the different parts of these Nexus devices are distributed our source code now I've chosen to use a nexus 5x really the nexus is the easiest devices for building the AOSP project and the binaries are available inside the project repository need to download them and unpack them inside of your build environment now once you have the binaries the source and the build environment setup the next thing to do is to choose the build type and you do that using the lunch tool and then you've got a whole bunch of options there you just pick the one for your particular device then once that's all set up you can actually go ahead and start the build process using make now again this process can take quite a while several hours again depending on the performance of your machine so be prepared to let this thing just churn away in the background until it's finished building the whole project and then once you have a built firmware or you get a success from that make command you then need to make sure the or bootloader is unlocked on your Nexus device and then you can flash over the new ROM onto the device now as I've said the instructions are pretty good that Google provide however there probably are some pitfalls and some bumps that you going to meet along the way and I've done this whole process recently and I've got over in the written article all the different tricks and tips I learned on how to make the build successful I'll give an example is one stage during the make process where I was constantly running out of memory even though I've got a gigabytes now there are ways around that and I've got that listed over in the article so please go and read article because I always expect in this recent process has been dumped out there I think you'll find that useful if you hit a barrier during this build process now if you make a download and build the firmware and flash it on to your device first of all congratulations well done that's a big step in this process now the next thing we're going to do is modify Android so that we can say we have our own custom very very slightly custom of course but our own custom version of Android and we going to do two things first of all we're going to modify the messaging app that's the app that's used for SMS messaging just to be slightly different something that we've added to it ourselves and secondly we're going to modify the Settings app so that we can have the build name and the build number of this rom inside of the settings okay let's go ahead and modify the messaging app what you need to do is you need to change directory into packages apps and then inside they need to find the messaging app which is in packages app messaging then drill down through source comm Android messaging and edit the file called bugle application Java now bugle application Java is basically the entry point into the messaging app now scroll down art of a long list of import statements you want to import the toast widget and you do that using this line of code now once you've added that in now go down to the oncreate function that's the function that's called when the app is first started and add in these two following lines of code towards the bottom of the function you they need to save that file CD back up to the beginning of your working directory the root of your working directory and then start another make and that will recompile the necessary files and produce a new system image which you can then flash on over to your device now once it's flashed over at the device reboots go into the meshing app and you will notice that the first time you open the messaging app a nice little toast appears at the bottom saying welcome it's a minor change but it just shows you that we can modify the Java code of these core apps and get them to do the things that we won't want to do now no self-respecting ROM would be without its settings page that tells you the name of the ROM maybe the name of the author when it was built the version number and so on we're just going to add two fields to the setting page in the about phone section to just talk about the name of our ROM and the version number so to do that you need to go into packages apps settings res XML and find the device info settings XML file and then right down at the bottom just before the preference screen close tag you need to add in these lines of code now as you can see they basically give us a preference we talked about the wrong name whiz-bang pop ROM and the ROM build number seven point zero point one I get you to follow the same process save that file go back up to the root of your working directory rebuild the Android Open Source project flash it over onto your device and then when it reboots go to settings go to about phone and you'll see those two new fields that you have added in there well done now it was like it add as a caveat that's really a hack what I've just done there with the settings page really all strings need to be defined in strings.xml under each of the individual languages that are supported by your wrong these are hard-coded strings it's the wrong way to do it but it's the quickest way to show you for this video if you're going to do any serious open source Android project development then you need to make sure you do it right you rings dot XML now let me just emphasize that what we've done here are some very simple changes however the principles are exactly the same you modify the Java code or you modify the XML for the layout and for the user interface and you make it you compile it and then you flash it on to your test device now again we've made some very small modifications however with more work and more effort you can make a more and more customized version of Android well my name is Gary Simms from anger Authority I hope you enjoyed this video if you did please do give it a thumbs up also don't forget to subscribe to handle authorities youtube channel definitely download the endless royalty app because that is a great place to get all the latest news and features directly on your mobile phone and also never forget to visit and refer calm because we are your source for all things Android now I'm glad you what hits into the video because I want to tell you I've now got a new green screen what do you think about my new green screen please tell me in the comments you think I should use it more in the future use it less I'd love to hear what you think because a new thing for me and I'm just playing around with it your opinion please