它已经上市一个月了，但 Android 3.0 的生态环境却没有显示出应有的活力，至今只有约 50 款专用软件上架

移动开发者 Justin Williams 在接受《连线》采访时说：“当年苹果的做法很明智，在 iPad 推出之前几个月就放出了开发工具。相比之下，Google 的开发者只是在 XOOM 发售之前几天才拿到开发工具。”所以在 iPad 发售时，商店里已经有了 1000 个专用软件。当 XOOM 发售时，这个数字是 15 。

还有另外一个原因导致开发者的热情不足，就是 Google 只把系统代码开放给了几个大厂商，例如摩托罗拉，三星，HTC 。大多数设备制造商和开发者根本接触不到 Android 3.0 的代码和技术细节，所以拖累了软件的开发进度

Google 的开源政策使 Android 迅速成长，但是在这个过程中，Android 分裂和用户体验差的批评就一直没有停止过。对于各厂商的定制，Google 一直采取放任的态度，因为这对 Google 核心业务的影响不大

但是最近发生的一些事情已经让 Google 不安了，一是 Amazon 发布了自己的 Android Appstore。Amazon是一个很强大的内容提供商，而且可能会推出平板产品。如果 Amazon 和其它硬件厂商合作，或推出自己的 Android 产品，使 Amazon Appstore 与 Android 更好的整合，将会威胁到 Android Market。

这两股潮流结合起来，Android 生态圈面临着失控的危险。我想，这就是 Google 宁可挨着“不开源”的骂名，将 HoneyComb 的代码暂时封闭起来的原因

I had the same issue. Along with including android:xlargeScreens="true" I found this to be the fix.

The Android Market treats as though requesting a permission like CALL_PHONE also requests: <uses-feature android:name="android.hardware.telephony" /> The XOOM does not have telephony — the first Android Market-compliant device with that limitation. While it can have a data plan, it has no voice or SMS capability, and so it is treated as not having android.hardware.telephony. But, if you request permissions like CALL_PHONE, the Android Market by default will assume you need android.hardware.telephony. As a result, you will be filtered out of the Market for the XOOM. The solution is simple: for any hardware features that might be implied by permissions but that you do not absolutely need, manually add the appropriate element to your manifest with android:required="false": <uses-feature android:name="android.hardware.telephony" android:required="false" />

虽然 BGR 认为 XOOM 还是无法替代笔记本电脑，但是强大的硬件、令人印象深刻的规格配备以及专门为平板准备的系统，让 XOOM 仍不失为一款非常棒的产品。即便不够创新，与 iPad 相比在易用性、直观性以及软件选择上也没有做得更好，也一定会赢得很多消费者的青睐

电力表现不俗，标称 18-20 小时，TC 的编辑经过十小时的正常使用（音乐、读书、浏览网页）以后，还能剩余 67% 的电量，对于普通用户来说，应该是绰绰有余了

总体来说，从硬件上 XOOM 超越了 iPad，在工业设计和美学方面和 iPad 也是同一档次，只是已经非常出色的 Honeycomb 系统在易用性上还无法跟 iOS 相比。除此之外，XOOM 无疑是当今市场最好的平板电脑

距离 iPad 2 发布会越来越近，各种传言也越来越多，包括 iPad 2 会更轻更薄、会在发布之日就开始发售等等。一起来看看之前的各种猜测，期待一下即将到来的发布活动吧

ifanr 将在 3 月 3 日凌晨两点在微博、Live 和推上为大家同步转播 iPad 2 发布会，敬请期待

If you add multiple changes to the transaction (such as another add() or remove()) and call addToBackStack(), then all changes applied before you call commit() are added to the back stack as a single transaction and the BACK key will reverse them all together.

The most significant difference in lifecycle between an activity and a fragment is how one is stored in its respective back stack. An activity is placed into a back stack of activities that's managed by the system when it's stopped, by default (so that the user can navigate back to it with the BACK key, as discussed in Tasks and Back Stack). However, a fragment is placed into a back stack managed by the host activity only when you explicitly request that the instance be saved by calling addToBackStack() during a transaction that removes the fragment.

In some cases, you might need a fragment to share events with the activity. A good way to do that is to define a callback interface inside the fragment and require that the host activity implement it. When the activity receives a callback through the interface, it can share the information with other fragments in the layout as necessary.

Rhodes is an open source Ruby-based framework to rapidly build native apps for all major smartphone operating systems (iPhone, Windows Mobile, RIM, Symbian and Android). These are true native device applications (NOT mobile web apps) which work with synchronized local data and take advantage of device capabilities such as GPS, PIM contacts and calendar, camera, native mapping, push, barcode, signature capture, and Bluetooth.