OEMs can choose to use these data files when creating time zone updates for their devices or can create their own data files if preferred. This data is then used by code from the following libraries in the Android source tree:.
The distro files also contain metadata that allows devices to detect versioning issues. The distro file format is Android-release dependent because the contents change with the ICU version, Android platform requirements, and other release changes. Android provides distro files for supported Android releases for every IANA update in addition to updating the platform system files. To keep their devices up to date, OEMs can use these distro files or create their own using the Android source tree which contains the scripts and other files needed to generate distro files.
A time zone rules update involves the transmission of distro files to a device and the safe installation of the files contained within. Transfer and installation requires the following:. The Android source tree contains generic source code for the above components, which the OEM can choose to use without modification. Test code is provided to enable OEMs to automatically check that they've enabled the feature correctly. The end-to-end installation process is asynchronous and split across three OS processes.
At any point during the installation, the device may lose power, run out of disk space, or encounter other issues, causing the installation check to be incomplete. In the best unsuccessful case, the Updater app informs the system server that it was unsuccessful; in the worst unsuccessful case, the RulesManagerService receives no call at all. To handle this, the system server code keeps track of whether a triggered update check has completed and what the last checked version code of the Data App is.
When the device is idle and charging, the system server code can check the current state. If it discovers an incomplete update check or unexpected Data App version, it spontaneously triggers an update check. When enabled, the RulesManagerService code in the system server performs several checks to ensure that the system is safe to use.
The Data app is expected to have a dedicated, OEM-specific package name and key. Before starting, OEMs should review the following policy, quality assurance, and security considerations:.
Example templates include both a build target for the real Data app APK and extra targets for creating test versions of the Data app. OEMs can customize the Data app with their own icon, name, translations, and other details. The Data app is intended to be built with a tapas build that produces APKs suitable to be added to the system image for the initial release and signed and distributed through an app store for subsequent updates.
For details on using tapas, see Building the Data app using tapas. The example templates also include build targets for including test versions of the Data app in test suites. To do this, the system image build must explicitly include the Updater app and Data app prebuilt targets. The Updater app should be signed with the platform key and included as any other system app. The Data app inclusion is OEM-specific and depends on the target name chosen for the prebuild.
Configuration overrides should be in the system image not vendor or other as a misconfigured device can refuse to boot. OEMs that have such test suites can add the Android time zone update tests provided in the following locations:. OEMs using the stock Android system and distro files can pick up these commits, use them to create a new version of their Data app, then release the new version to update their devices in production.
For example, if an OEM wants to provide updates for Android 8. In this step, OEMs update the version code of the Data app. The build automatically picks up distro.
For details, see the example version code strategy scheme ; if the example scheme or a similar scheme is used, the test version codes don't need to be updated because they're guaranteed to be higher than the real version codes. OEMs are responsible for quality assurance and testing the updated Data app on their devices before release.
The Data app must have a suitable versioning strategy to ensure that devices receive the correct APKs. For example, if a system update is received that contains an older APK than one downloaded from the app store, the app store version should be retained. Currently, platform API level is strongly correlated to distro format version because each API level is usually associated with a new version of ICU which makes the distro files incompatible. In the future, Android may change this so that a distro file can work across multiple Android platform releases and API level isn't used in the Data app version code scheme.
This example versioning number scheme ensures that higher distro format versions supersede lower distro format versions. The scheme could be packed better if binary were used instead of decimal, but this scheme has the advantage of being human-readable. If the full number range is exhausted, the Data app package name could change. Examples are shown in the following table.
As each device ships with a default, appropriately versioned APK in the system image, there's no risk of an O-MR1 version being installed on a P device because it has a lower version number than a P system image version. OEMs are responsible for managing most aspects of the time zone Data app and configuring the system image correctly.
Tapas is a slimmed-down version of the Android build system that uses a reduced source tree to produce distributable versions of apps. OEMs familiar with the normal Android build system should recognize the build files from the normal Android platform build. A reduced source tree is usually achieved with a custom manifest file that refers only to the Git projects needed by the build system and for building the app.
The app build leverages several other Git projects that are shared with the platform build or contain OEM-independent code libraries. The following manifest snippet contains the minimal set of Git projects needed to support an O-MR1 build of the time zone Data app. OEMs must add their OEM-specific Git projects which typically include a project that contains the signing certificate to this manifest, and may configure different branches accordingly.
After the source tree is established, invoke the tapas build using the following commands:. Content and code samples on this page are subject to the licenses described in the Content License. Docs Getting Started About. Core Topics Architecture. Overview Architecture. Modular System Components. Modular Kernels. HIDL General. In that regard, using a broadcast receiver seems to me like a Rube Goldberg way of doing this. But if you wish to update the textview to display the date and time to the minute, it should perform the task you need it to.
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Publish your app. Command line tools. Android Developers. Updates for Android Studio are available from the following release channels: Canary channel : These are bleeding-edge releases, updated roughly weekly, and available for download at developer. Dev channel : These are hand-picked canary builds that survived a full round of internal testing. Beta channel : These are release candidates based on stable canary builds, released to get feedback before going into the stable channel.
Stable channel : The official stable release that is available for download at developer. Be sure that Automatically check for updates is checked, then select a channel from the drop-down list see figure 1. Click Apply or OK. Figure 1. The Android Studio Updates preferences. To update an item or install a new one, click the check box so it shows a checkmark. To uninstall a package, click to clear the check box.
Figure 2. Includes tools to build Android apps. Includes various tools required by the Android platform, including the adb tool. Includes essential tools such as ProGuard.
Android Emulator Recommended. A QEMU-based device-emulation tool that you can use to debug and test your applications in an actual Android runtime environment. See the Android Emulator release notes. At least one platform is required in your environment so you're able to compile your application. In order to provide the best user experience on the latest devices, use the latest platform version as your build target. You'll still be able to run your app on older versions, but you must build against the latest version in order to use new features when running on devices with the latest version of Android.
The system image is required in order to run the Android Emulator. Each platform version contains the supported system images. Select either Intel or ARM based on your development computer's processor. Click Add at the bottom of the window.
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