Android class libraries are written in C/C++ but java is the preferred language for developing applications.Why not C/C++ instead of java ?
If you prefer to develop via C/C++ you may use the NDK. The Android platform is run on the Dalvik Virtual Machine, what you code in java is actually compiled to Dalvik bytecode and run on the VM.
They spent a lot of time developing the facilities to make it fairly painless to make an Android application using a managed language. Some people would consider this an advantage.
There are many reasons to choose Java as the platform, but my guess as to the biggest reason why would be to not expose application developers to a slew of porting issues that arise from the sheer number of devices that Android powers. There would be far fewer apps available if every developer had to research every platform nuance for every phone and tablet out there.
Obviously, there are drawbacks, and that's why the Native Development Kit (NDK) exists. The NDK primarily addresses performance issues, but recent additions have included the ability to write an entire app completely in native code.
Java it's used in many application for mobile devices, it is a standard because it is more manageble, even the new languages that are appearing now it's based in java. It is a open language and you can learn it without going to class. Javame is used for mobile devices which incorporates some features of J2EE and adds new classes for the small devices.
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I currently work for a company which gave me an application implemented by a former student. They completely wrapped (even the main) an existing C++ application with SWIG.
The application was first designed to work on a desktop and now they want to make it work on an android phone.
My questions are:
Is that possible for the application to work knowing they didn't succeed to wrap all
the libraries?
Is there another way to do this?
Is it necessary to write the main in Java and call the C++ libraries?
Any idea will be welcome!
I have doubts about there is a automatic utility like SWIG will work to convert PC -> Android - Android OS have significantly different architecture.
Look at Android NDK - it is a development kit supporting the features called JNI in usual Java applications.
You can include C++ libraries in your Android applications with Android NDK. So it is the way to develop cross-platform applications.
I plan to create an SDK (involving huge data manipulations), which can used to create applications on Android.
I plan to develop the complete SDK, including the libraries in Java, for the reason that if I implement my libraries in the native language(C++) the data movement between the Java and the native layer will involve memory copies and will make my application look slow.
I plan to port the same SDK later to other platforms like Windows Mobile. I am a bit confused on the better approach to code in such cases, keeping in mind the portability and performance of the SDK.
Inputs will be greatly appreciated.
Windows Mobile supports native code (Visual C++, see Getting Started in Developing Applications for Windows Mobile) so using the Android NDK would be a good option. At least you wouldn't have to write the whole thing from scratch. You could have the common code base written in C/C++ and only write the Java wrappers for Android.
As you know, Windows Phone 7 (the successor to Windows Mobile) uses C# and whatever approach you take on Android, you'd need to rewrite the SDK from scratch anyway. Windows Phone 7.x might be supporting native code (C/C++) sometime in the future but not anytime soon.
How diferent is Java used in Android apps development from Java used to develop regular desktop applications? Can I use the skills acquired by developing Java Android applications in Java EE web development?
What is Java ME all about ?
How diferent is Java used in Android apps development from java used to develop regular java applications?
From a language point of view, almost identical.
From an user interface API and application life-cycle point of view, almost completely different.
Can i use the skills acquired by developing Java Android applications in Java EE web development?
Yes. Your pure "Java-skills" will come in handy for sure. But as said above, the application life-cycle for instance, is completely different from most other scenarios.
What is Java ME all about ?
JavaME is an older technique, typically used for phones without touch screens. It defines (compared to Android) a very minimal API and was originally designed to run on very limited devices compared to todays smart phones.
Android is, roughly, JavaSE without some of the more specialized features, like security layers (JSE and JAAS), GUI (AWT, Swing and Java2D).
Android's API uses the JavaME class hierarchie for OpenGL ES.
So if you know Android, you can easily move to JavaSE development.
JavaEE relies on JavaSE, but it's about server applications, so you will have to learn how it works. Look for servlets, JSP and JSF to learn more about it.
JavaME is slightly different than JavaSE. JavaME's API is smaller and less powerful than JavaSE, and slightly different.
Well, in order to develop both for Android, Java ME and Java EE the base thing to know is Java SE. Java ME is getting old. The most popular staff to develop in Java ME is software for Blackberry.
Java EE development is pretty hard to learn technology, cause it actually consists of a big ammount of frameworks and smaller technologies. It's complicated because of many things, but, definately in order to use it you should start learning Hibernate/JPA, Java SE, RMI and OOP itself. Then you may look into Spring technology.
For Android Java is about a programming language and some core java library
J2ME is also a mobile application development framework supported by many phones. The common thing between Android and J2ME is only the Java language. Both have different set of terminology for development.
Web: It's about target platform and programming model. Android's Java is for mobile development platform. Here the apis, software stack, concepts are totally different from what are there for Web development.
Recently I have to develop on mobile phones using Java and I am planning to do the development on the following brands:
Nokia
Samsung
SonyEricsson
Motorola
LG
I've browsed the "developer site" of each company and looks like they all have provided their own SDKs for J2ME development.
I am really new to this field and I have a few questions:
Since they all support Java platform, why do we need additional Java SDKs?
What can I benefit from the SDKs?
What determines whether I should use the SDKs or not?
It all depends on how complex the application your want to develop will be.
Developing a basic application to run on that many different handsets is doable but complexity will increase exponentially with each advanced feature you add, especially if you want to target existing, old and upcoming devices.
What you also need to consider is that each manufacturer can support several operating systems and platforms.
Nokia has Series40 (3rd and 5th editions), Series60 (2nd, 3rd and 5th editions), Series80.
Samsung has at least 2 major versions of their own platform and the last 2 editions of Series60
SonyEricsson has 3 major versions of their JP8 platform (and JP7 too), Series60 5th edition, UIQ 2.x and UIQ 3.x
Series80, Series60, UIQ 2.x and UIQ 3.x are based on the Symbian operating system. Different versions of Symbian OS have used different JVMs and several companies have contributed JSR implementations.
Motorola has at least 2 major versions of their own platform and a couple UIQ devices
1 - Since they all support Java platform, why do we need additional Java SDKs?
The major problem of J2ME is fragmentation. For a variety of reasons (both good and bad, both technical and commercial), the Java promise of "Write Once, Run Anywhere" is largely considered utterly unfulfilled in the mobile industry.
Many functionalities need to be coded in a platform-specific way if you want the same code to work on many platforms at once.
Many J2ME platforms also add non-standard APIs, properties, configurations, "bugs"...
Most importantly, manufacturer SDKs are supposed to allow things like on-device debugging or MIDlet deployment over USB. They provide basic or extended tools that help on-device testing because that is an area where a generic WTK should typically be lacking.
2 - What can I benefit from the SDKs?
Very probably, yes.
Ok, so, most of them will only run on a Windows desktop computer but the SDKs themselves should be free.
3 - What determines whether I should use the SDKs or not?
Start with the WTK. When you realize you're trying to do something that is specific to the handset manufacturer, get the corresponding SDK.
One example: The WTK PDAPDemo sample application contains a rudimentary filesystem browser. It displays widely different results on different platforms.
As suggested by Pavel Alexeev, DeviceAnywhere is a great tool, assuming you have a proper test budget. Nokia also offers something similar but that is obviously limited to Nokia handsets.
Benefit from vendor-specific SDKs is only if you want to use vendor-specific APIs. In most cases Sun WTK would be enough.
As for testing purposes, I would not suggest to rely on emulators. You better try on-device testing. Nokia and Samsung provide remove device access for recent devices. And you can also try deviceanywhere.
I would do most of my development with the regular old Sun..err...Oracle Java WTK, and then if you need to do some testing, get the emulators/SDK's from those companies. Other than that I'd mostly avoid them though.
Built in camera functionality typically differs between different brands of phone and the API's provided can be very helpful when trying to do anything more advanced than take a simple snapshot. SonyEricsson phones for example will allow you to display a camera feed through a VideoCamera directly to a canvas which is very fast but does not not allow you to control how frequently the feed is drawn to the screen. In order to draw graphics on top of the video feed without excessive flickering you need to add the OVERLAY flag (1<<8) to the VideoCamera's initDisplayMode() call, not all brands support the additional flag.
For .NET guys - there is a Ubiq Mobile framework. Ubiq Mobile apps work on Android, iOS, Windows Phone and Java-based phones and tablets. This is rapid cross-platform development with .NET with cloud-based architecture. Getting started article: How to create simple UbiqMobile application with video.
My opinion is "QuickRecipesOnSymbianOS" is correct. It is very easy, simple and technical answer.
I am developing mobile apps for some time in .NET and I was always wondering if the grass is greener on the other side (Java).
Thus, I would like to ask your opinion about which one you prefer for your mobile apps and why is that so.
The main advantage of using Java is the broader installed base. If you use Java, you are going to reach orders of magnitude more phones than if you use .NET.
As far as I know, .NET works exclusively with Windows Mobile phones.
On the other hand, Mobile .NET is easier than Java (IMHO), and that's partly because of Visual Studio IDE which makes life so much simpler than any other development environment on the Java World. For example, doing Form Based applications in .NET mobile is really straightforward and simple.
So, the answer will basically depend on what you are trying to accomplish:
Trying to reach to the biggest number of mobile devices: go with Java
Trying to develop an application for Windows Mobile devices: go with .NET
Trying to develop an application that will run only on a controlled environment (A single business) where you get to decide the devices it will run on: decide which device you are going to use and then pick development environment.
Keep in mind that if you are talking about Java for Android or Blackberry development, you will face the same issue of not reaching to a huge installed base that you will with .NET. If you want the huge installed base, go with plain Java Mobile Edition.
I can only speak for windows mobile development stay with .net.
Sun don't even release a JVM for windows mobile devices I have developed for windows devices using java and using http://www2s.biglobe.ne.jp/~dat/java/project/jvm/index_en.html as my JVM which was very good the author even responded to a feature request I made.
It is true that if you're going to develop for WindowsMobile, J2ME is not a very good option. More than likely your device of choice will not come with a JVM and if it does, it'll be buggy and slow. Also, forget about trying to integrate with with OS at more than a basic level.
Just to add to what others have said, Sun has made phoneME available and if you want to go that route and deploy your MIDlet and VM together that is certainly a possibility. It's just a lot of work at this point.
For .NET guys - there is a Ubiq Mobile framework. Ubiq Mobile apps work on Android, iOS, Windows Phone and Java-based phones and tablets. This is rapid cross-platform development with .NET with cloud-based architecture. Getting started article: How to create simple UbiqMobile application with video.