PreviewChannelHelper

@WorkerThread
class PreviewChannelHelper

From a user's perspective, the TV home screen has two types of channels: the single Live Channels row versus the App preview Channels. This class is concerned with App Channels; or more precisely: your app's preview Channels. In API 26+, all TV apps are allowed to create multiple channels and publish those Channels to the home screen.

This class provides convenience methods to help you publish, update and delete channels; add, update or remove programs in a channel. You do not need to know anything about Content Providers, Content Resolvers, Cursors or such to publish your channels. This class abstracts away all database interactions for you.

To make it easy for you to distinguish classes that help you build App Channels, the support library uses the prefix Preview- to denote the classes that pertain to app Channels. Hence, the classes PreviewChannel and PreviewProgram help your app add channels to the TV home page. All calls to methods in the class should be made on worker threads.

Summary

Public constructors
PreviewChannelHelper(
    context: Context!,
    urlConnectionTimeoutMillis: Int,
    urlReadTimeoutMillis: Int
)

Public functions
Unit

Removes a preview channel from the system's content provider (aka TvProvider).
Unit

Removes programs from a preview channel.
(Mutable)List<PreviewChannel!>!

The TvProvider does not allow select queries.
PreviewChannel?
getPreviewChannel(channelId: Long)

Retrieves a single preview channel from the TvProvider.
PreviewProgram?
getPreviewProgram(programId: Long)

Retrieves a single preview program from the system content provider (aka TvProvider).
WatchNextProgram?

Retrieves a single WatchNext program from the system content provider (aka TvProvider).
Long

Publishing a channel to the TV home screen is a two step process: first, you add the channel to the TV content provider; second, you make the channel browsable (i.e. visible).
Long

This is a convenience method that simply publishes your first channel for you.
Long

Adds programs to a preview channel.
Long

Adds a program to the Watch Next channel
Unit
updatePreviewChannel(channelId: Long, update: PreviewChannel)

To update a preview channel, you need to use the PreviewChannel.Builder to set the attributes you wish to change.
Unit
updatePreviewProgram(programId: Long, update: PreviewProgram)

Updates programs in a preview channel.
Unit

Updates a WatchNext program.

Protected functions
Bitmap!
downloadBitmap(logoUri: Uri)

Downloads a Bitmap from a remote server.

Public constructors

PreviewChannelHelper

Added in 1.1.0
PreviewChannelHelper(context: Context!)

PreviewChannelHelper

Added in 1.1.0
PreviewChannelHelper(
    context: Context!,
    urlConnectionTimeoutMillis: Int,
    urlReadTimeoutMillis: Int
)
Parameters
context: Context!

the Context object that holds the channels
urlConnectionTimeoutMillis: Int

see setConnectTimeout
urlReadTimeoutMillis: Int

see setReadTimeout

Public functions

deletePreviewChannel

Added in 1.1.0
fun deletePreviewChannel(channelId: Long): Unit

Removes a preview channel from the system's content provider (aka TvProvider).

deletePreviewProgram

Added in 1.1.0
fun deletePreviewProgram(programId: Long): Unit

Removes programs from a preview channel.

getAllChannels

Added in 1.1.0
fun getAllChannels(): (Mutable)List<PreviewChannel!>!

The TvProvider does not allow select queries. Hence, unless you are querying for a single PreviewChannel by id, you must get all of your channels at once and then use the returned list as necessary.

getPreviewChannel

Added in 1.1.0
fun getPreviewChannel(channelId: Long): PreviewChannel?

Retrieves a single preview channel from the TvProvider. When you publish a preview channel, the TvProvider assigns an ID to it. That's the channelId to use here.

Parameters
channelId: Long

ID of preview channel in TvProvider
Returns
PreviewChannel?

PreviewChannel or null if not found

getPreviewProgram

Added in 1.1.0
fun getPreviewProgram(programId: Long): PreviewProgram?

Retrieves a single preview program from the system content provider (aka TvProvider).

getWatchNextProgram

Added in 1.1.0
fun getWatchNextProgram(programId: Long): WatchNextProgram?

Retrieves a single WatchNext program from the system content provider (aka TvProvider).

publishChannel

Added in 1.1.0
fun publishChannel(channel: PreviewChannel): Long

Publishing a channel to the TV home screen is a two step process: first, you add the channel to the TV content provider; second, you make the channel browsable (i.e. visible). This method adds the channel to the TV content provider for you and returns a channelId. Next you must use the channelId to make the channel browsable. There are two ways you can make a channel browsable: a) For your first channel, simply ask the system to make the channel browsable: TvContractCompat.requestChannelBrowsable(context,channelId) b) For any additional channel beyond the first channel, you must get permission from the user. So if this channel is not your first channel, you must request user permission through the following intent. So take the channelId returned by this method and do the following inside an Activity or Fragment: 

intent = new Intent(TvContractCompat.ACTION_REQUEST_CHANNEL_BROWSABLE);
intent.putExtra(TvContractCompat.EXTRA_CHANNEL_ID, channelId);
startActivityForResult(intent, REQUEST_CHANNEL_BROWSABLE);

Creating a PreviewChannel, you may pass to the builder a url as your logo. In such case, updatePreviewChannel will load the logo over the network. To use your own networking code, override downloadBitmap.

Returns
Long

channelId or -1 if insertion fails. This is the id the system assigns to your published channel. You can use it later to get a reference to this published PreviewChannel.
Throws
java.io.IOException

publishDefaultChannel

Added in 1.1.0
fun publishDefaultChannel(channel: PreviewChannel): Long

This is a convenience method that simply publishes your first channel for you. After calling publishChannel to add the channel to the TvProvider, it calls requestChannelBrowsable to make the channel visible.

Only use this method to publish your first channel as you do not need user permission to make your first channel browsable (i.e. visible on home screen). For additional channels, see the documentations for publishChannel.

Creating a PreviewChannel, you may pass to the builder a url as your logo. In such case, updatePreviewChannel will load the logo over the network. To use your own networking code, override downloadBitmap.

Returns
Long

channelId: This is the id the system assigns to your published channel. You can use it later to get a reference to this published PreviewChannel.
Throws
java.io.IOException

publishPreviewProgram

Added in 1.1.0
fun publishPreviewProgram(program: PreviewProgram): Long

Adds programs to a preview channel.

publishWatchNextProgram

Added in 1.1.0
fun publishWatchNextProgram(program: WatchNextProgram): Long

Adds a program to the Watch Next channel

updatePreviewChannel

Added in 1.1.0
fun updatePreviewChannel(channelId: Long, update: PreviewChannel): Unit

To update a preview channel, you need to use the PreviewChannel.Builder to set the attributes you wish to change. Then simply pass in the built channel and the channelId of the preview channel. (The channelId is the ID you received when you originally published the preview channel.)

Creating a PreviewChannel, you may pass to the builder a url as your logo. In such case, updatePreviewChannel will load the logo over the network. To use your own networking code, override downloadBitmap.

Throws
java.io.IOException

updatePreviewProgram

Added in 1.1.0
fun updatePreviewProgram(programId: Long, update: PreviewProgram): Unit

Updates programs in a preview channel.

updateWatchNextProgram

Added in 1.1.0
fun updateWatchNextProgram(upgrade: WatchNextProgram, programId: Long): Unit

Updates a WatchNext program.

Protected functions

downloadBitmap

Added in 1.1.0
protected fun downloadBitmap(logoUri: Uri): Bitmap!

Downloads a Bitmap from a remote server. It is declared protected to allow you to override it to use your own networking implementation if you so wish.

Throws
java.io.IOException