Dr. Dobb's | Smartphone Operating Systems: A Developer's Perspective | March 30, 2009 - 0 views
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The industry stewards have countered Apple's move with their own application stores, so there's a huge opportunity to write the "killer app" for one of several smartphone platforms.
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40 MB to less than 4 MB of free RAM
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one-app-at-a-time requirement complicates any implementation of a copy-and-paste mechanism.
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As a security sandbox, the iPhone OS permits only one third-party application to run at a time, and not in the background.
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adding some useful Bluetooth profiles that supported stereo headsets, data synchronization, or the ability to implement multiplayer games would be usefu
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iPhone OS 3, that provides some of the missing features mentioned here, such as the A2DP profile for Bluetooth, voice recording, and copy-and-paste.
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Have to learn Objective-C; is only smartphone platform that uses it.
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Competitors will soon catch up on the UI.
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embed navigation and GPS plotting into applications.
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provide their own map content
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The OS now supports the use of accessories connected to the iPhone either through its 30-pin docking connector or wirelessly via Bluetooth. Now that the device has been "opened", you can expect an entire ecosystem to build up around the device, much like the iPod has.
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peer-to-peer connectivity using Bonjour
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developers can now allow users, from within the application, to purchase and obtain new content
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No voice dial.
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A client-server mechanism provides access to low-level system resources, and in fact the kernel itself is a server that parcels out resources to those applications that need them. This transaction scheme allows applications to exchange data without requiring direct access to the OS space.
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C/C++ for porting existing UNIX applications, and Java to port Java ME MIDlets. As mentioned previously, the software stack offers several run-times that offer application development using WRT widgets, Flash, and Python. The primary programming language for the platform is Symbian C++,
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Handango has managed the wide-scale distribution of Nokia applications. In February, Nokia announced plans to launch its Ovi Store, which sells applications, videos, games, pod-casts and other content, similar to Apple's App Store. The store will be accessible by Nokia S60 smartphones in May.
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Non-standard Symbian C++ has steep learning curve, with special idioms to master. Large number of Symbian APIs to learn, since it contains hundreds of classes and thousands of member functions.
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BlackBerry Device Software executes multiple applications simultaneously
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Manages multiple e-mail Exchange e-mail accounts, along with support for POP3 and SMTP, and e-mails can have file attachments
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FIPS 140-2 compliant, and supports AES or Triple DES encryption sessions via BlackBerry Enterprise Servers
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BlackBerry Device Software has enhanced the capabilities of the platform with its own Java virtual machine (JVM), along with new Java classes that offer multitasking capabilities and UI enhancements to go beyond the capabilities of Java ME.
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You can also take existing Java ME code and add specific BlackBerry classes to make a hybrid Java ME application
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don't intermix MIDP 2.0 and BlackBerry API calls that perform either screen drawing or application management.
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The catch to writing an application that uses BlackBerry API extensions is that it ties the application this smartphone. However, this is no worse than using the unique Java classes found in Google's Android.
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Apple promotes the design goal that applications should accomplish one purpose.
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no Flash support, and you can't download files.
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For non-Exchange users, Apple's MobileMe online service, after some fits and starts in 2008, now supports the push of e-mails and changes to the calendar and contacts.
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The iPhone 3G can work in tandem with Microsoft Exhange Server 2003 and 2007 to support enterprise operations.
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Cocoa Touch is a subset of Apple's Cocoa,
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Cocoa Touch components manage most of the writing to the screen and playing media, yet there are APIs exposed that let you access the accelerometer and camera.
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Quartz engine is identical to the one found in Mac OS X
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Only a select few higher-level frameworks have access to the kernel and drivers. If necessary, an application can indirectly access some of these services through C-based interfaces provided in a LibSystem library.
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the SDK provides Dashcode, which is a framework based on a Web page composed of HTML and Javascript. You can use DashCode's simulator to write and test your web application. You can also use several other third-party frameworks to write web applications, and debug these with Aptanna Studio's tools.
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Made by HTC, the G1 is the first smartphone using the Android platform.
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e-mail program (which makes use of Google's Gmail), a mapping program (using the company's Google Maps), and a browser that uses WebKit, not Google's Chrome web browser
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Android is not Java ME, nor does it support such applications
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ability to both browse and manage multiple IM conversations. On the other hand, such heavy use of the smartphone's CPU shortens battery life significantly. Maybe Apple is on to something in limiting the number of applications that the platform can run.
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On the positive side, the Android APIs support a touch interface (and the G1 has a capacitive touch screen), but not any multi-touch gestures.
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copying text from the web pages is the browser isn't allowed
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The advantage to Android's use of a different bytecode interpreter is that the DVM was designed so that multiple instances of it can run, each in their own protected memory space, and each executing an application. While this approach offers stability and a robust environment for running multiple applications, it does so at the expense of compatibility with Java ME applications.
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Seasoned Java programmers will find the Android SDK an amalgam of Java SE and Java ME methods and classes, along with unique new ones
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compile the Java code to generate Dalvik bytecode files, with an extension of .dex. These files, along with the manifest, graphics files, and XML files, are packaged into an .apk file that is similar to a Java JAR file.
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The certificate that you use to generate the private key does not require a signing authority, and you can use self-signed certificates for this purpose.
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The Developer Phone provides access to a shipping Android device without the cash outlay or contract contortions required when developing for the other platforms.
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in February the site began supporting priced applications. Google allows developers to take seventy percent of the proceeds.
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it's possible that you might pick up a malicious application before it is detected by the user community.
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Open source, open platform: if you hate the mail program, some third-party is writing a better one.
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Lengthy developer's overview of Symbian, Mac OS X iPhone, Blackberry, Android. This talks about the leading app platforms except Java ME and Windows Mobile, though it does explain how Blackberry and Symbian support Java ME.
