| page.title=Optimizing Apps for Chromebooks |
| @jd:body |
| |
| <div id="qv-wrapper"> |
| <div id="qv"> |
| <h2>On this page</h2> |
| |
| <ol> |
| <li><a href="#update-manifest">Update Your App's Manifest File</a></li> |
| <li><a href="#leverage">Leverage Support for Multi-Window Mode</li> |
| <li><a href="#keyboard">Support the Keyboard, Trackpad, and Mouse</a></li> |
| <li><a href="#backup">Use Backup and Restore Effectively</a></li> |
| <li><a href="#update-ndk">Update the NDK Libraries</a></li> |
| <li><a href="#support-new-features">Plan Support for New Android Features</a></li> |
| <li><a href="#testing">Test Your App</a></li> |
| <li><a href="#setup">Set Up ADB</a></li> |
| <li><a href="#learning-materials">Additional Learning Materials</a></li> |
| </ol> |
| </div> |
| </div> |
| |
| <p> |
| Google Chromebooks now support the Google Play Store and Android apps. This |
| document describes some ways that you can optimize your Android apps for |
| Chromebooks. |
| </p> |
| |
| <h2 id="update-manifest">Update Your App's Manifest File</h2> |
| |
| <p> |
| To begin optimizing your Android app for Chromebooks, update your manifest file |
| (<code>AndroidManifest.xml</code>) to account for some key hardware and software |
| differences between Chromebooks and other devices running Android. |
| </p> |
| |
| <p> |
| As of Chrome OS version M53, all Android apps that don't explicitly require the |
| <a |
| href="{@docRoot}guide/topics/manifest/uses-feature-element.html#touchscreen-hw-features"><code>android.hardware.touchscreen</code></a> |
| feature will also work on Chrome OS devices that support the |
| <code>android.hardware.faketouch</code> feature. However, if you want your app |
| to work on all Chromebooks in the best possible way, go to your manifest file |
| and adjust the settings so that the <code>android.hardware.touchscreen</code> |
| feature is not required, as shown in the following example. You should also |
| review your mouse and keyboard interactions. |
| </p> |
| |
| <pre> |
| <manifest xmlns:android="http://schemas.android.com/apk/res/android" |
| ... > |
| <!-- Some Chromebooks don't support touch. Although not essential, |
| it's a good idea to explicitly include this declaration. --> |
| <uses-feature android:name="android.hardware.touchscreen" |
| android:required="false" /> |
| </manifest> |
| </pre> |
| |
| <p> |
| Different devices often have different sensors available in them. See the <a |
| href="https://developer.android.com/guide/topics/sensors/sensors_overview.html">Sensors |
| Overview</a> document for an overview of all sensors that the Android platform |
| supports. Although Android handheld devices may have GPS and accelerometers, |
| sensors are not guaranteed to be available in every Chromebook. However, there |
| are cases where the functionality of a sensor is provided in another way. For |
| example, Chromebooks may not have GPS sensors, but they still provide location |
| data based on Wi-Fi connections. If you want your app to run on Chromebooks, |
| regardless of sensor support, you should update your manifest file so that none |
| of the sensors are required. |
| </p> |
| |
| <p class="note"><strong>Note</strong>: If you don't require a particular sensor |
| for your app but still use measurements from the sensor when it's available, |
| make sure you dynamically check for the sensor's availability before trying to |
| gather information from it in your app. |
| </p> |
| |
| <p> |
| Some software features are unsupported on Chromebooks. For example, apps that |
| provide custom IMEs, app widgets, live wallpapers, and app launchers aren't |
| supported and won't be available for installation on Chromebooks. For a complete |
| list of software features that aren't currently supported on Chromebooks, see <a |
| href="{@docRoot}topic/arc/manifest.html#incompat-software-features">incompatible |
| software features</a>. |
| </p> |
| |
| <h2 id="leverage">Leverage Support for Multi-Window Mode</h2> |
| |
| <p> |
| The implementation of Android apps on Chrome OS includes basic multi-window |
| support. Instead of automatically drawing over the full screen, Android renders |
| apps on Chrome OS into layouts that are appropriate for this form factor. Google |
| provides support for the most common window layouts: |
| |
| <ul> |
| <li> |
| <strong>Portrait</strong> – Similar to Nexus 5. |
| </li> |
| <li> |
| <strong>Landscape</strong> – Similar to Nexus 7. |
| </li> |
| <li> |
| <strong>Maximized</strong> – Uses all available screen pixels. |
| </li> |
| </ul> |
| |
| <p> |
| In addition, end users are presented with window controls to toggle among all |
| available layouts. By choosing the correct orientation option, you can ensure |
| that the user has the correct layout upon launching the app. If an app is |
| available in portrait and landscape, it defaults to landscape if possible. After |
| this option is set, it is remembered on a per-app basis. Google recommends that |
| you test your app to ensure that it handles changes in window size |
| appropriately. |
| </p> |
| |
| <h2 id="keyboard">Support the Keyboard, Trackpad, and Mouse</h2> |
| |
| <p> |
| All Chromebooks have a physical keyboard and a trackpad, and some Chromebooks |
| have a touchscreen as well. Some devices can even convert from a laptop to a |
| tablet. |
| </p> |
| |
| <p> |
| Many existing apps already support mouse and trackpad interactions with no extra |
| work required. However, it's always best to adjust your app's behavior |
| appropriately when users interact with it using a trackpad instead of a |
| touchscreen, and you should support and distinguish between both interfaces |
| properly. Given the support for physical keyboards, you can now provide hotkeys |
| to enable your app's users to be more productive. For example, if your app |
| supports printing, you can use <strong>Ctrl+P</strong> to open a print dialog. |
| </p> |
| |
| <h2 id="backup">Use Backup and Restore Effectively</h2> |
| |
| <p> |
| One of the strongest features of Chromebooks is that users can easily migrate |
| from one device to another. That is, if someone stops using one Chromebook and |
| starts using another, they simply have to sign in, and all of their apps appear. |
| </p> |
| |
| <p class="note"><strong>Tip: </strong> Although it's not mandatory, backing up |
| your app's data to the cloud is a good idea. |
| </p> |
| |
| <p> |
| Chromebooks can also be shared among a large number of people, such as in |
| schools. Since local storage is not infinite, entire accounts—together |
| with their storage—can be removed from the device at any point. For |
| educational settings, it's a good idea to keep this scenario in mind. |
| </p> |
| |
| <h2 id="update-ndk">Update the NDK Libraries</h2> |
| |
| <p> |
| If your app uses the Android NDK libraries, and its target SDK version is 23 or |
| higher, ensure that text relocations are removed from both the ARM and x86 |
| versions of your NDK libraries, as they're not compatible in Android 6.0 (API |
| level 23) and higher. By leaving text relocations in your NDK libraries, you may |
| also cause incompatibility errors with Chromebooks, especially when running on |
| a device that uses an x86 architecture. |
| </p> |
| |
| <p class="note"><strong>Note: </strong>To view more details on updating NDK |
| libraries properly, see the <a |
| href="https://developer.android.com/about/versions/marshmallow/android-6.0-changes.html#behavior-runtime"> |
| Runtime</a> section of the Android 6.0 Changes document. |
| </p> |
| |
| <h2 id="support-new-features">Plan Support for New Android Features</h2> |
| |
| <p> |
| Android apps on Chromebooks initially ship with APIs for Android 6.0 (API level |
| 23). By following the best practices outlined above, your app is likely to be |
| compatible with the multi-window improvements introduced in Android 7.0 (API |
| level 24). It's good to plan support for the APIs and behaviors available as of |
| Android 7.0, which feature several improvements. For example, multi-window |
| support is better integrated, and you're able to resize activities arbitrarily, |
| making them feel more natural. You can also access APIs for drag-and-drop |
| operations across apps and mouse cursor control. |
| </p> |
| |
| <h2 id="testing">Test Your App</h2> |
| |
| <p> |
| To <a href="{@docRoot}topic/arc/sideload.html">load</a> your app onto your |
| Chromebook for testing, you must enter <em>Developer</em> mode on your Chrome OS |
| device and enable <em>unknown sources</em>. See the <a class="external-link" |
| href="https://www.chromium.org/chromium-os/poking-around-your-chrome-os-device#TOC-Putting-your-Chrome-OS-Device-into-Developer-Mode"> |
| Putting your Chrome OS Device into Developer Mode</a> document for detailed |
| instructions about moving your device into Developer mode. After your device is |
| in Developer mode, you can go to your Chrome settings and select <strong>Enable |
| Unknown Sources</strong> under the <em>security in app</em> settings. |
| </p> |
| |
| <p> |
| After enabling Developer mode, you can load an Android app onto your Chrome OS |
| device using one of several methods. For more details, see the <a |
| href="{@docRoot}topic/arc/sideload.html#load-app">Load Your App</a> section of |
| the Loading Apps on Chromebooks page. |
| </p> |
| |
| <p class="note"><strong>Note: </strong>To ensure that your Android app works |
| well on a variety of Chromebook devices and available form factors, Google |
| recommends that you test your app on an ARM-based Chromebook, an x86-based |
| Chromebook, a device with a touchscreen and one without one, and on a |
| convertible device (one that can change between a laptop and a tablet). To view |
| the full list of supported devices, see the <a |
| href="{@docRoot}topic/arc/device-support.html">Chrome OS Device Support for |
| Apps</a> page.</p> |
| |
| <h2 id="setup">Set Up ADB</h2> |
| |
| <p> |
| Before attempting to set up an ADB connection, you must start your Chrome OS in |
| <a class="external-link" |
| href="https://www.chromium.org/chromium-os/poking-around-your-chrome-os-device"> |
| Developer Mode</a> so that you have the ability to install Android apps on the |
| Chromebook. |
| </p> |
| |
| <p class="caution"><strong>Caution: </strong>After switching your Chrome OS |
| device to Developer mode, it restarts and clears all existing data on the |
| device. |
| </p> |
| |
| <p> |
| To set up ADB, complete the following steps: |
| </p> |
| |
| <ol> |
| <li> |
| Press <strong>Ctrl+D</strong> to start your device. |
| </li> |
| <li> |
| Finish the setup process. |
| </li> |
| <li> |
| Log into your test account. |
| </li> |
| <li> |
| Accept the Google Play Store terms and service conditions. |
| </li> |
| </ol> |
| |
| <h3>Configure the firewall</h3> |
| |
| <p> |
| To configure the Chrome OS firewall to allow incoming ADB connections, complete |
| the following steps: |
| </p> |
| |
| <ol> |
| <li> |
| Press <strong>Ctrl+Alt+T</strong> to start the Chrome OS terminal. |
| </li> |
| <li> |
| Type <strong>shell</strong> to get to the bash command shell: |
| <pre class="no-pretty-print"> |
| crosh> shell |
| chronos@localhost / $ |
| </pre> |
| </li> |
| <li> |
| Type the following commands to set up developer features and enable |
| disk-write access for the firewall settings changes: |
| <pre class="no-pretty-print"> |
| chronos@localhost / $ sudo /usr/libexec/debugd/helpers/dev_features_rootfs_verification |
| chronos@localhost / $ sudo reboot |
| </pre> |
| The <em>sudo reboot</em> command restarts your Chromebook. |
| <p class="note"><strong>Note</strong>: You can press the <strong>Tab</strong> |
| key to enable autocompletion of file names.</p> |
| </li> |
| <li> |
| After your device restarts, log in to your test account and type the |
| following command to enable the <em>secure shell</em> and configure the |
| firewall properly: |
| <pre class="no-pretty-print"> |
| chronos@localhost / $ sudo /usr/libexec/debugd/helpers/dev_features_ssh |
| </pre> |
| You can now exit out of the shell. |
| </li> |
| </ol> |
| |
| <p class="note"><strong>Note</strong>: You must complete this procedure only |
| once on your Chromebook.</p> |
| |
| <h3>Check the IP address of your Chromebook</h3> |
| |
| <p> |
| To verify the IP address of your Chromebook, complete the following steps: |
| </p> |
| |
| <ol> |
| <li> |
| Click the clock icon in the bottom-right area of the screen. |
| </li> |
| <li> |
| Click <strong>Settings</strong>. |
| </li> |
| <li> |
| The <em>Internet Connection</em> section in the Settings area lists all of |
| the available networks. Select the one that you want to use for ADB. |
| </li> |
| <li> |
| Take note of the IP address that appears. |
| </li> |
| </ol> |
| |
| <h3>Enable ADB debugging</h3> |
| |
| <p> |
| To enable ADB debugging, complete the following steps: |
| </p> |
| |
| <ol> |
| <li> |
| Click the clock icon in the bottom-right area of the screen. |
| </li> |
| <li> |
| Click <strong>Settings</strong>. |
| </li> |
| <li> |
| In the <em>Android Apps</em> section, click the <strong>Settings</strong> |
| link in the line that reads <em>Manage your Android apps in Settings</em>. |
| This brings up the Android apps settings. |
| </li> |
| <li> |
| Click <strong>About device</strong>. |
| </li> |
| <li> |
| Click <strong>Build number</strong> seven times to move into Developer mode. |
| </li> |
| <li> |
| Click the arrow in the top-left area of the window to go back to the main |
| Settings screen. |
| </li> |
| <li> |
| Click the new <strong>Developer options</strong> item, activate <strong>ADB |
| debugging</strong>, and then click <strong>OK</strong> to allow ADB |
| debugging. |
| </li> |
| <li> |
| Return to your development machine and use ADB to connect to your |
| Chromebook's using its IP address and port 22. |
| </li> |
| <li> |
| On your Chromebook, click <strong>Allow</strong> when prompted whether you |
| want to allow the debugger. Your ADB session is established. |
| </li> |
| </ol> |
| |
| <h4>Troubleshooting ADB debugging</h4> |
| |
| <p> |
| Sometimes the ADB device shows that it's offline when everything is connected |
| properly. In this case, complete the following steps to troubleshoot the issue: |
| </p> |
| |
| <ol> |
| <li> |
| Deactivate <strong>ADB debugging</strong> in <em>Developer options</em>. |
| </li> |
| <li> |
| In a terminal window, run <code>adb kill-server</code>. |
| </li> |
| <li> |
| Re-activate the <strong>ADB debugging</strong> option. |
| </li> |
| <li> |
| In a terminal window, attempt to run <code>adb connect</code>. |
| </li> |
| <li> |
| Click <strong>Allow</strong> when prompted whether you want to allow |
| debugging. Your ADB session is established. |
| </li> |
| </ol> |
| |
| <h2 id="learning-materials">Additional Learning Materials</h2> |
| |
| <p> |
| To learn more about optimizing your Android apps for Chromebooks, consult the |
| following resources: |
| </p> |
| |
| <ul> |
| <li> |
| Review the |
| <a class="external-link" href="http://android-developers.blogspot.com/2016/05/bring-your-android-app-to-chromebooks.html"> |
| Bring your Android App to Chromebooks</a> I/O session. |
| </li> |
| <li> |
| Post a question on the <a class="external-link" |
| href="https://plus.sandbox.google.com/+AndroidDevelopers">Android developer |
| community</a> with hashtag <em>#AndroidAppsOnChromeOS</em>. |
| </li> |
| </ul> |