Android Dev

The Android Market engineering team has been hard at work on improving the Android Market experience for users and developers. Today, I’m pleased to announce a significant update to the Android Market client. Over the next two weeks, we’ll be rolling out a new Android Market client to all devices running Android 1.6 or higher.This new Market client introduces important features that improve merchandising of applications, streamline the browse-to-purchase experience, and make it easier for developers to distribute their applications.

To make it easier for developers to distribute and manage their products, we will introduce support for device targeting based on screen sizes and densities, as well as on GL texture compression formats. We are also increasing the maximum size for .apk files on Market to 50MB, to better support richer games.

To streamline the browse-to-purchase experience, users can now access all the information about an application on a single page without the need to navigate across different tabs.

To find your minimum width and height in density-independent pixels (dp), use this formula: (number of cells * 74) - 2

how often the App Widget framework should request an update from the AppWidgetProvider by calling the onUpdate() method

exactly on time

The question is: How do I reference the Android default icons? In XML this would be: android:icon="@android:drawable/ic_menu_info_details

android.R.drawable.ic_menu_info_details

Current Instapaper and former Tumblr developer Marco Arment wonders out loud if Google Android phones can ever achieve the levels of usability and polish Apple’s iPhone has arguably had since day one

Android will continue to exhibit what Google does best: great low-level engineering and tight integration with Google’s other services. But it’s never going to be Apple-like in user experience, polish, or design. Attention to detail, like most facets of truly good design, can’t be (and never is) added later. It’s an entire development philosophy, methodology, and culture

Android 2.2 是一次增补式的更新，但仅靠效率提升一点就让它成为 Android 狂热者的重要升级。提升的响应速度和更平滑的界面过渡大大提升了用户体验。 几个新功能——特别是批量升级——提供了立即可用的明显好处。其它功能，如 SD 卡程序存储和云备份，可能要在 Android 开发者大量应用后才能体现真正的价值。我对云端信息服务特别有兴趣——这应该能够极大的丰富 Android，为程序开发社区开启创新之门。 Google 积极的开发努力将 Android 快速向前推进。和两年前相比，系统更成熟了。2.2 版本新增的 JIT 大大解决了 Android 的效率问题，赋予了它前所未有的竞争力。Google 正在向 3.0 迈进，用户界面似乎会有大革新，我们很有可能看到更多创新

You're required to select a category for your application. On December 22, 2010, the available category types changed in the Developer Console. The original categories were renamed, merged, or split into new categories. We believe this will enhance the user experience significantly; the new categories will rolling out to users over the course of a week.

Gson is a Java library that can be used to convert Java Objects into its JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.

In portrait orientation, each cell is 80 pixels wide by 100 pixels tall (the diagram shows a cell in portrait orientation)

In landscape orientation, each cell is 106 pixels wide by 74 pixels tall.

Additionally, you can feel free to use the Search bar selection mechanism as a replacement for tabs since it’s really just a fast pivot on a data set. If you have more than 3 data sets, tabs become problematic since no more than 3 can be onscreen at once. For example, look at how we implemented the Profile switching mechanism below:

The good news for developers is you get this highly functional contacts feature for free if users choose to sync contact information into your app

The good news for developers is you get this highly functional contacts feature for free if users choose to sync contact information into your app. QuickContact for Android provides instant access to a contact's information and communication modes.

Intent videoClient = new Intent(Intent.ACTION_VIEW);    videoClient.setData(Uri.parse("http://m.youtube.com/watch?v="+videoId));    videoClient.setClassName("com.google.android.youtube", "com.google.android.youtube.PlayerActivity");    startActivityForResult(videoClient, VIDEO_APP);

Android的发展完全是爆发性的，就是在这一年内，Android从1.5版本瞬间升级到 2.3（1.5-1.6-2.0.1-2.1-2.2-2.2.1-2.3），由于苹果的升级基本上属于强制性的，也就是说基本上是同一时间端升级，除了 iphone 2G已经不再升级之外，大部分的iphone都会升级到最新的版本，对于开发者来说，只需要通过最新的SDK开发程序或者升级程序就可以了，而 Android开发者就会非常郁闷，原因是由于谷歌仅仅控制软件最基本的代码，准确的说就是Android非硬件部分的规范，而对于硬件方面，由于各个厂商的不同，所以就需要各个厂商自行调整，因此会存在当系统都是升级到2.3的时候，部分机型依旧是1.6版，对于正常的产品周期来看，必定会让购买了 1.6系统机型的用户相当不满

而Android的发展完全是爆发性的，就是在这一年内，Android从1.5版本瞬间升级到 2.3（1.5-1.6-2.0.1-2.1-2.2-2.2.1-2.3），由于苹果的升级基本上属于强制性的，也就是说基本上是同一时间端升级，除了 iphone 2G已经不再升级之外，大部分的iphone都会升级到最新的版本，对于开发者来说，只需要通过最新的SDK开发程序或者升级程序就可以了，而 Android开发者就会非常郁闷，原因是由于谷歌仅仅控制软件最基本的代码，准确的说就是Android非硬件部分的规范，而对于硬件方面，由于各个厂商的不同，所以就需要各个厂商自行调整，因此会存在当系统都是升级到2.3的时候，部分机型依旧是1.6版，对于正常的产品周期来看，必定会让购买了 1.6系统机型的用户相当不满。 这并不是Android自身开发的怠慢，一年多个6个版本明显是超越iOS，但是由于硬件上自身调试的原因，并不是所有的玩家都能及时享受到最新版本，严重的滞后阻碍了Android系列手机的应用开发和用户体验

从目前市场行业角度上分析，我觉得后期Android的发布将会和现在的很多开源软件一样，会采用双线并行的方式，即一个开发版本和一个稳定维护版本，首先谷歌会宣布几款设备将不会升级至2.X系，逐步将其淘汰，然后将2.X版本作为稳定开发版本，SDK也主要是为这个版本开发放出，并且保证大部分机型在这个版本系列上得到充分支持，而开发版本则是高端的3.X系列，为不稳定版本，官方不会放出相关的SDK给开发者，用于平台预览，但是会对几款高端机型提供相应的固件下载，保证了高端的GEEK玩家的需求，在2.X进入稳定期以后将会采用小版本号更新，如2.X.X这样，五年以后停止版本的官方支持，并且转移至更高的版本，（这一点上有点类似于mysql）我觉得这样会是一个比较稳妥的解决版本的方法。

It allows third-party application servers to send lightweight messages to their Android applications. The messaging service is not designed for sending a lot of user content via the messages. Rather, it should be used to tell the application that there is new data on the server, so that the application can fetch it. C2DM makes no guarantees about delivery or the order of messages. So, for example, while you might use this feature to tell an instant messaging application that the user has new messages, you probably would not use it to pass the actual messages. An application on an Android device doesn’t need to be running to receive messages. The system will wake up the application via Intent broadcast when the the message arrives, as long as the application is set up with the proper broadcast receiver and permissions.

It uses an existing connection for Google services. This requires users to set up their Google account on their mobile devices.

C2DM imposes the following limitations: The message size limit is 1024 bytes. Google limits the number of messages a sender sends in aggregate, and the number of messages a sender sends to a specific device

stay around

whose lifecycle is separate from the current context

If used from an Activity context, the receiver is being registered within that activity.

Adobe Reader for Android支持多指手势，包括双指缩放、双击缩放、拖动等等，还包括一个新的reflow模式，会将宽度又宽文字又多的页面在小屏幕上也能方便阅读。不过Adobe Reader for Android不支持搜索，不支持那些被密码保护的文档。 在菜市场里搜索Adobe Reader for Android就可以找到。