Google 已推出 Android M Developer Preview 2，System Image 已经可以下载，而 OTA 亦应会在未来数天推出 (对呀，Nexus机若安装了 Android M 也会有 OTA 更新)。
Android M Developer Preview 2 System Image 下载
http://developer.android.com/preview/download.html
今次 Developer Preview 2 在界面上有多项改动，Launcher 支援横向 Landscape 模式, App Drawer 不再以字母排序, Widget 选择界面亦改善。另外，通知栏内的通知亦有改动，例如 Screenshot 后的通知，可以选择分享或删除；亦可显示剩余电量数值等。其他还有一系列的权限改动，还有改进了API, 修正了权限等问题。
Permissions changes
– The android.permission.USE_FINGERPRINT permission now has “normal” protection level, so it is no longer necessary to request this permission directly from the user. The USE_FINGERPRINT permission enables fingerprints to be enabled for authentication, but does not give the requesting app access to the enrollment/fingerprint administration flow.
– The android.permission.WRITE_EXTERNAL_STORAGE permission has protection level “dangerous”, meaning that apps wanting to write to external storage will need to request permission from the user at runtime. Both WRITE_EXTERNAL_STORAGE and WRITE_EXTERNAL_STORAGE are members of the STORAGEpermission group.
– Remote Bluetooth/Wi-Fi MAC’s now require either the android.permission.LOCATION_FINE orandroid.permission.LOCATION_COURSE permission.
– Some accounts and identity permissions are moved to CONTACTS permissions group and others are removed or granted based on account type. In particular, android.permission.USE_CREDENTIALS,android.permission.MANAGE_ACCOUNTS, and android.permission.AUTHENTICATE_ACCOUNTS are ungrouped pending further changes in a later release.
– The Wi-Fi permissions android.permission.CHANGE_WIFI_STATE,android.permission.CHANGE_WIMAX_STATE, and android.permission.CHANGE_WIFI_MULTICAST_STATEnow have protection level “normal”.
– The Bluetooth permissions android.permission.BLUETOOTH andandroid.permission.BLUETOOTH_ADMIN now have protection level “normal”.
– Bookmarks and subscribed feeds permissions are removed.
– Apps included in the system image are no longer granted dangerous permissions automatically. All apps should check for and request permissions at runtime.
– Introduces the utility method Activity.shouldShowRequestPermissionRationale(String), which lets your app see whether users have previously rejected a permission request. This lets you know that your app should explain the the user why it needs that permission. For more information see the Permissions developer guide.
Other changes
– The android.app.AssistContent and android.app.AssistStructure classes are moved into a new package, android.app.assist.
– Bluetooth Stylus APIs are updated and include new callback events. TheView.OnStylusButtonPressListener class is renamed to View.OnContextClickListener andGestureDetector.OnStylusButtonPressListener class to GestureDetector.OnContextClickListener.
– TextInputLayout doesn’t set hint for embedded EditText. (fixed issue)
– Camera Permission issue with Legacy Apps (fixed issue)
Source: Android Developer
