Android api 27 documentation download

For example, another app launched through a voice interaction can also send an intent to launch a voice interaction. To determine if your activity launched from a user voice query or from another voice interaction app, call the isVoiceInteractionRoot method. If another app launched your activity, the method returns false.

Your app may then prompt the user to confirm that they intended this action. To learn more about implementing voice actions, see the Voice Actions developer site. This release offers a new way for users to engage with your apps through an assistant. To use this feature, the user must enable the assistant to use the current context. Once enabled, the user can summon the assistant within any app, by long-pressing on the Home button. In addition to the standard set of information that the platform passes to the assistant, your app can share additional information by using the new AssistContent class.

With this release, users can adopt external storage devices such as SD cards. Adopting an external storage device encrypts and formats the device to behave like internal storage. This feature allows users to move both apps and private data of those apps between storage devices.

When moving apps, the system respects the android:installLocation preference in the manifest. If your app accesses the following APIs or fields, be aware that the file paths they return will dynamically change when the app is moved between internal and external storage devices.

When building file paths, it is strongly recommended that you always call these APIs dynamically. This release provides improved support for user input using a Bluetooth stylus. Users can pair and connect a compatible Bluetooth stylus with their phone or tablet. While connected, position information from the touch screen is fused with pressure and button information from the stylus to provide a greater range of expression than with the touch screen alone.

Your app can listen for stylus button presses and perform secondary actions, by registering View. OnContextClickListener objects in your activity.

Use the MotionEvent methods and constants to detect stylus button interactions:. If your app performs performs Bluetooth Low Energy scans, use the new setCallbackType method to specify that you want the system to notify callbacks when it first finds, or sees after a long time, an advertisement packet matching the set ScanFilter.

This release adds support for the Hotspot 2. To provision Hotspot 2. The new isPasspointNetwork method indicates if a detected network represents a Hotspot 2. The platform now allows apps to request that the display resolution be upgraded to 4K rendering on compatible hardware. To query the current physical resolution, use the new Display. Mode APIs. If the UI is drawn at a lower logical resolution and is upscaled to a larger physical resolution, be aware that the physical resolution the getPhysicalWidth method returns may differ from the logical resolution reported by getSize.

This feature is useful if you want to switch to 4K display resolution. While in 4K display mode, the UI continues to be rendered at the original resolution such as p and is upscaled to 4K, but SurfaceView objects may show content at the native resolution. Theme attributes are now supported in ColorStateList for devices running on Android 6.

The Resources. If you are calling these APIs, call the new Context. These methods are also available in the v4 appcompat library via ContextCompat.

This set of libraries provides APIs for essential app architecture tasks like lifecycle management and data persistence, so you can write modular apps with less boilerplate code. Learn more. The Android Support Library offers backward-compatible versions of a number of features, including others not built into the framework.

The Data Binding Library enables you to write declarative layouts. Android Test helps you build and run test code for your app. The Google Play Billing Library provides a simple interface for sending billing requests and managing billing transactions with Google Play. You can install and run your app on the Android Emulator faster than with a physical device.

It simulates various device configurations and hardware sensors, and it uses a snapshot to quickly resume exactly where you left off. Android Studio uses Gradle, an advanced build toolkit, to automate the build process, while allowing you to define flexible, custom build configurations. Android Studio includes a layout editor that allows you to build and preview your app UI by dragging elements into a visual design editor instead of writing layout XML by hand.

You can also retrieve this color information. To create a WallpaperColors object, do either of the following:. To retrieve the primary, secondary, or tertiary color details from the wallpaper, call the following methods:. To notify the system about any significant color changes in your live wallpaper, call the notifyColorsChanged method.

This method triggers an onComputeColors lifecycle event where you have an opportunity to provide a new WallpaperColors object. To add a listener for color changes, you can call the addOnColorsChangedListener method. You can also call the getWallpaperColors method to retrieve the primary colors of a wallpaper. The FingerprintManager class has introduced the following error codes:. Content and code samples on this page are subject to the licenses described in the Content License.

All Android releases Android 9. Features and APIs. Behavior changes. Android Developers. Android Oreo Go edition Android Go is our initiative to optimize the Android experience for billions of people coming online around the world. For example, if the API level of an Android device is lower than the minimum API level that you specify for your app, the Android device will prevent the user from installing your app.

The following sections explain how to use the SDK Manager to prepare your development environment for the API levels you want to target, followed by detailed explanations of how to configure Target Framework , Minimum Android version , and Target Android version settings in Xamarin. This setting specifies what APIs your app expects to use when it runs, but it has no effect on which APIs are actually available to your app when it is installed.

As a result, changing the Target Framework setting does not change runtime behavior. The Target Framework identifies which library versions your application is linked against — this setting determines which APIs you can use in your app. For example, if you want to use the NotificationBuilder. SetCategory method that was introduced in Android 5. We recommend that you always compile with the latest available Target Framework version.

Doing so provides you with helpful warning messages for any deprecated APIs that might be called by your code. Using the latest Target Framework version is especially important when you use the latest support library releases — each library expects your app to be compiled at that support library's minimum API level or greater.

To access the Target Framework setting in Visual Studio, open the project properties in Solution Explorer and select the Application page:. To access the Target Framework setting in Visual Studio for Mac, right-click the project name and select Options ; this opens the Project Options dialog. Set the Target Framework by selecting an API level in the drop-down menu to the right of Target framework as shown above. By default, an app can only be installed on devices matching the Target Framework setting or higher; if the Minimum Android version setting is lower than the Target Framework setting, your app can also run on earlier versions of Android.

For example, if you set the Target Framework to Android 7. Although your app may successfully build and install on this range of platforms, this does not guarantee that it will successfully run on all of these platforms. For example, if your app is installed on Android 5. Therefore, your code must ensure — at runtime — that it calls only those APIs that are supported by the Android device that it is running on.

In other words, your code must include explicit runtime checks to ensure that your app uses newer APIs only on devices that are recent enough to support them. Runtime Checks for Android Versions , later in this guide, explains how to add these runtime checks to your code. In the drop-down menu under Minimum Android version you can select the Minimum Android version for your application:. To access the Minimum Android version in Visual Studio for Mac, right-click the project name and select Options ; this opens the Project Options dialog.

Using the drop-down menu to the right of Minimum Android version , you can set the Minimum Android version for your application:. If you select Automatic — use target framework version , the Minimum Android version will be the same as the Target Framework setting.

Android uses this setting to determine whether to enable any compatibility behaviors — this ensures that your app continues to work the way you expect. Android uses the Target Android version setting of your app to figure out which behavior changes can be applied to your app without breaking it this is how Android provides forward compatibility.

The Target Framework and the Target Android version, while having very similar names, are not the same thing. Android for use at compile time , while the Target Android version communicates target API level information to Android for use at run time when the app is installed and running on a device. To access this setting in Visual Studio, open the project properties in Solution Explorer and select the Android Manifest page.

In the drop-down menu under Target Android version you can select the Target Android version for your application:. We recommend that you explicitly set the Target Android version to the latest version of Android that you use to test your app.