Handling TV Hardware

TV hardware is substantially different from other Android devices. TVs do not include some of the hardware features found on other Android devices, such as touch screens, cameras, and GPS receivers. TVs are also completely dependent on secondary hardware devices. In order for users to interact with TV apps, they must use a remote control or game pad. When you build an app for TV, you must carefully consider the hardware limitations and requirements of operating on TV hardware.

This lesson discusses how to check if your app is running on a TV, how to handle unsupported hardware features, and discusses the requirements for handling controllers for TV devices.

Check for a TV Device

If you are building an app that operates both on TV devices and other devices, you may need to check what kind of device your app is running on and adjust the operation of your app. For instance, if you have an app that can be started through an Intent, your application should check the device properties to determine if it should start a TV-oriented activity or a phone activity.

The recommended way to determine if your app is running on a TV device is to use the UiModeManager.getCurrentModeType() method to check if the device is running in television mode. The following example code shows you how to check if your app is running on a TV device:

public static final String TAG = "DeviceTypeRuntimeCheck";

UiModeManager uiModeManager = (UiModeManager) getSystemService(UI_MODE_SERVICE);
if (uiModeManager.getCurrentModeType() == Configuration.UI_MODE_TYPE_TELEVISION) {
    Log.d(TAG, "Running on a TV Device")
} else {
    Log.d(TAG, "Running on a non-TV Device")
}

Handle Unsupported Hardware Features

Depending on the design and functionality of your app, you may be able to work around certain hardware features being unavailable. This section discusses what hardware features are typically not available for TV, how to detect missing hardware features, and suggests alternatives to using these features.

Unsupported TV hardware features

TVs have a different purpose from other devices, and so they do not have hardware features that other Android-powered devices often have. For this reason, the Android system does not support the following features for a TV device:

Hardware	Android feature descriptor
Touchscreen	android.hardware.touchscreen
Touchscreen emulator	android.hardware.faketouch
Telephony	android.hardware.telephony
Camera	android.hardware.camera
Bluetooth	android.hardware.bluetooth
Near Field Communications (NFC)	android.hardware.nfc
GPS	android.hardware.location.gps
Microphone [1]	android.hardware.microphone
Sensors	android.hardware.sensor

[1] Some TV controllers have a microphone, which is not the same as the microphone hardware feature described here. The controller microphone is fully supported.

See the Features Reference for a complete list of features, subfeatures, and their descriptors.

Declaring hardware requirements for TV

Android apps can declare hardware feature requirements in the app manifest to ensure that they do not get installed on devices that do not provide those features. If you are extending an existing app for use on TV, closely review your app's manifest for any hardware requirement declarations that might prevent it from being installed on a TV device.

If your app uses hardware features (such as a touchscreen or camera) that are not available on TV, but can operate without the use of those features, modify your app's manifest to indicate that these features are not required by your app. The following manifest code snippet demonstrates how to declare that your app does not require hardware features which are unavailable on TV devices, even though your app may use these features on non-TV devices:

<uses-feature android:name="android.hardware.touchscreen"
        android:required="false"/>
<uses-feature android:name="android.hardware.faketouch"
        android:required="false"/>
<uses-feature android:name="android.hardware.telephony"
        android:required="false"/>
<uses-feature android:name="android.hardware.camera"
        android:required="false"/>
<uses-feature android:name="android.hardware.bluetooth"
        android:required="false"/>
<uses-feature android:name="android.hardware.nfc"
        android:required="false"/>
<uses-feature android:name="android.hardware.location.gps"
        android:required="false"/>
<uses-feature android:name="android.hardware.microphone"
        android:required="false"/>
<uses-feature android:name="android.hardware.sensor"
        android:required="false"/>

Note: Some features have subfeatures like android.hardware.camera.front, as described in the Feature Reference. Be sure to mark as required="false" any subfeatures also used in your app.

All apps intended for use on TV devices must declare that the touch screen feature is not required as described in Get Started with TV Apps. If your app normally uses one or more of the features listed above, change the android:required attribute setting to false for those features in your manifest.

Caution: Declaring a hardware feature as required by setting its value to true prevents your app from being installed on TV devices or appearing in the Android TV home screen launcher.

Once you decide to make hardware features optional for your app, you must check for the availability of those features at runtime and then adjust your app's behavior. The next section discusses how to check for hardware features and suggests some approaches for changing the behavior of your app.

For more information on filtering and declaring features in the manifest, see the uses-feature guide.

Declaring permissions that imply hardware features

Some uses-permission manifest declarations imply hardware features. This behavior means that requesting some permissions in your app manifest can exclude your app from from being installed and used on TV devices. The following commonly requested permissions create an implicit hardware feature requirement:

Permission	Implied hardware feature
RECORD_AUDIO	android.hardware.microphone
CAMERA	android.hardware.camera and android.hardware.camera.autofocus
ACCESS_COARSE_LOCATION	android.hardware.location and android.hardware.location.network
ACCESS_FINE_LOCATION	android.hardware.location and android.hardware.location.gps

For a complete list of permission requests that imply a hardware feature requirement, see the uses-feature guide. If your app requests one of the features listed above, include a uses-feature declaration in your manifest for the implied hardware feature that indicates it is not required (android:required="false").

Checking for hardware features

The Android framework can tell you if hardware features are not available on the device where your app is running. Use the hasSystemFeature(String) method to check for specific features at runtime. This method takes a single string argument that specifies the feature you want to check.

The following code example demonstrates how to detect the availability of hardware features at runtime:

// Check if the telephony hardware feature is available.
if (getPackageManager().hasSystemFeature("android.hardware.telephony")) {
    Log.d("HardwareFeatureTest", "Device can make phone calls");
}

// Check if android.hardware.touchscreen feature is available.
if (getPackageManager().hasSystemFeature("android.hardware.touchscreen")) {
    Log.d("HardwareFeatureTest", "Device has a touch screen.");
}

Touch screen

Since most TVs do not have touch screens, Android does not support touch screen interaction for TV devices. Furthermore, using a touch screen is not consistent with a viewing environment where the user is seated 10 feet away from the display. Make sure that your UI elements and text do not require or imply the use of a touchscreen.

On TV devices, you should design your app to work with this interaction model by supporting navigation using a directional pad (D-pad) on a TV remote control. For more information on properly supporting navigation using TV-friendly controls, see Creating TV Navigation.

Camera

Although a TV typically does not have a camera, you can still provide a photography-related app on a TV. For example, if you have an app that takes, views, and edits photos, you can disable its picture-taking functionality for TVs and still allow users to view and even edit photos. If you decide to enable your camera-related app to work on a TV, add the following feature declaration your app manifest:

<uses-feature android:name="android.hardware.camera" android:required="false" />

If you enable your app to run without a camera, add code to your app that detects if the camera feature is available and makes adjustments to the operation of your app. The following code example demonstrates how to detect the presence of a camera:

// Check if the camera hardware feature is available.
if (getPackageManager().hasSystemFeature("android.hardware.camera")) {
    Log.d("Camera test", "Camera available!");
} else {
    Log.d("Camera test", "No camera available. View and edit features only.");
}

GPS

TVs are stationary, indoor devices, and do not have built-in global positioning system (GPS) receivers. If your app uses location information, you can still allow users to search for a location, or use a static location provider such as a zip code configured during the TV device setup.

// Request a static location from the location manager
LocationManager locationManager = (LocationManager) this.getSystemService(
        Context.LOCATION_SERVICE);
Location location = locationManager.getLastKnownLocation("static");

// Attempt to get postal or zip code from the static location object
Geocoder geocoder = new Geocoder(this);
Address address = null;
try {
  address = geocoder.getFromLocation(location.getLatitude(),
          location.getLongitude(), 1).get(0);
  Log.d("Zip code", address.getPostalCode());

} catch (IOException e) {
  Log.e(TAG, "Geocoder error", e);
}

Handling Controllers

TV devices require a secondary hardware device for interacting with apps, in the form of a basic remote controller or game controller. This means that your app must support D-pad input. It also means that your app may need to handle controllers going offline and input from more than one type of controller.

D-pad minimum controls

The default controller for a TV device is a D-pad. In general, your app should be operable from a remote controller that only has up, down, left, right, select, Back, and Home buttons. If your app is a game that typically requires a game controller with additional controls, your app should attempt to allow gameplay with these D-pad controls. In this case, your app should also warn the user that a controller is required and allow them to exit your game gracefully using the D-pad controller. For more information about handling navigation with D-pad controller for TV devices, see Creating TV Navigation.

Handle controller disconnects

Controllers for TV are frequently Bluetooth devices which may attempt to save power by periodically going into sleep mode and disconnecting from the TV device. This means that an app might be interrupted or restarted if it is not configured to handle these reconnect events. These events can happen in any of the following circumstances:

• While watching a video which is several minutes long, a D-Pad or game controller goes into sleep mode, disconnects from the TV device and then reconnects later on.
• During gameplay, a new player joins the game using a game controller that is not currently connected.
• During gameplay, a player leaves the game and disconnects a game controller.

Any TV app activity that is subject to disconnect and reconnect events must be configured to handle reconnection events in the app manifest. The following code sample demonstrates how to enable an activity to handle configuration changes, including a keyboard or navigation device connecting, disconnecting, or reconnecting:

<activity
  android:name="com.example.android.TvActivity"
  android:label="@string/app_name"
  android:configChanges="keyboard|keyboardHidden|navigation"
  android:theme="@style/Theme.Leanback">

  <intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LEANBACK_LAUNCHER" />
  </intent-filter>
  ...
</activity>

This configuration change allows the app to continue running through a reconnection event, rather than being restarted by the Android framework, which is not a good user experience.

Handle D-pad input variations

TV device users may have more than one type of controller that they use with their TV. For example, a user might have both a basic D-pad controller and a game controller. The key codes provided by a game controller when it is being used for D-pad functions may vary from the key codes sent by a physical D-pad.

Your app should handle the variations of D-pad input from a game controller, so the user does not have to physically switch controllers to operate your app. For more information on handling these input variations, see Handling Controller Actions.