Summary: Ctors | Methods | Protected Methods | Inherited Methods

PreviewChannelHelper

Kotlin |Java

public class PreviewChannelHelper
extends Object

java.lang.Object
↳	androidx.tvprovider.media.tv.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)`
`PreviewChannelHelper(Context context, int urlConnectionTimeoutMillis, int urlReadTimeoutMillis)`

Public methods
`void`	`deletePreviewChannel(long channelId)` Removes a preview channel from the system's content provider (aka TvProvider).
`void`	`deletePreviewProgram(long programId)` Removes programs from a preview channel.
`List<PreviewChannel>`	`getAllChannels()` The TvProvider does not allow select queries.
`PreviewChannel`	`getPreviewChannel(long channelId)` Retrieves a single preview channel from the TvProvider.
`PreviewProgram`	`getPreviewProgram(long programId)` Retrieves a single preview program from the system content provider (aka TvProvider).
`WatchNextProgram`	`getWatchNextProgram(long programId)` Retrieves a single WatchNext program from the system content provider (aka TvProvider).
`long`	`publishChannel(PreviewChannel channel)` 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.
`long`	`publishDefaultChannel(PreviewChannel channel)` This is a convenience method that simply publishes your first channel for you.
`long`	`publishPreviewProgram(PreviewProgram program)` Adds programs to a preview channel.
`long`	`publishWatchNextProgram(WatchNextProgram program)` Adds a program to the Watch Next channel
`void`	`updatePreviewChannel(long channelId, PreviewChannel update)` To update a preview channel, you need to use the `PreviewChannel.Builder` to set the attributes you wish to change.
`void`	`updatePreviewProgram(long programId, PreviewProgram update)` Updates programs in a preview channel.
`void`	`updateWatchNextProgram(WatchNextProgram upgrade, long programId)` Updates a WatchNext program.

Protected methods
`Bitmap`	`downloadBitmap(Uri logoUri)` Downloads a Bitmap from a remote server.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()`
`boolean`	`equals(Object arg0)`
`void`	`finalize()`
`final Class<?>`	`getClass()`
`int`	`hashCode()`
`final void`	`notify()`
`final void`	`notifyAll()`
`String`	`toString()`
`final void`	`wait(long arg0, int arg1)`
`final void`	`wait(long arg0)`
`final void`	`wait()`

Public constructors

PreviewChannelHelper

public PreviewChannelHelper (Context context)

Parameters
`context`	`Context`

PreviewChannelHelper

public PreviewChannelHelper (Context context, 
                int urlConnectionTimeoutMillis, 
                int urlReadTimeoutMillis)

Parameters
`context`	`Context`
`urlConnectionTimeoutMillis`	`int`: see `URLConnection.setConnectTimeout(int)`
`urlReadTimeoutMillis`	`int`: see `URLConnection.setReadTimeout(int)`

Public methods

deletePreviewChannel

public void deletePreviewChannel (long channelId)

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

Parameters
`channelId`	`long`

deletePreviewProgram

public void deletePreviewProgram (long programId)

Removes programs from a preview channel.

Parameters
`programId`	`long`

getAllChannels

public List<PreviewChannel> getAllChannels ()

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.

Returns
`List<PreviewChannel>`

getPreviewChannel

public PreviewChannel getPreviewChannel (long channelId)

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

public PreviewProgram getPreviewProgram (long programId)

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

Parameters
`programId`	`long`

Returns
`PreviewProgram`

getWatchNextProgram

public WatchNextProgram getWatchNextProgram (long programId)

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

Parameters
`programId`	`long`

Returns
`WatchNextProgram`

publishChannel

public long publishChannel (PreviewChannel channel)

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(long, PreviewChannel) will load the logo over the network. To use your own networking code, override downloadBitmap(Uri).

Parameters
`channel`	`PreviewChannel`

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
`IOException`

publishDefaultChannel

public long publishDefaultChannel (PreviewChannel channel)

This is a convenience method that simply publishes your first channel for you. After calling publishChannel(PreviewChannel) to add the channel to the TvProvider, it calls TvContractCompat.requestChannelBrowsable(Context, long) 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(PreviewChannel).

Parameters
`channel`	`PreviewChannel`

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
`IOException`

publishPreviewProgram

public long publishPreviewProgram (PreviewProgram program)

Adds programs to a preview channel.

Parameters
`program`	`PreviewProgram`

Returns
`long`

publishWatchNextProgram

public long publishWatchNextProgram (WatchNextProgram program)

Adds a program to the Watch Next channel

Parameters
`program`	`WatchNextProgram`

Returns
`long`

updatePreviewChannel

public void updatePreviewChannel (long channelId, 
                PreviewChannel update)

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.)

Parameters
`channelId`	`long`
`update`	`PreviewChannel`

Throws
`IOException`

updatePreviewProgram

public void updatePreviewProgram (long programId, 
                PreviewProgram update)

Updates programs in a preview channel.

Parameters
`programId`	`long`
`update`	`PreviewProgram`

updateWatchNextProgram

public void updateWatchNextProgram (WatchNextProgram upgrade, 
                long programId)

Updates a WatchNext program.

Parameters
`upgrade`	`WatchNextProgram`
`programId`	`long`

Protected methods

downloadBitmap

protected Bitmap downloadBitmap (Uri logoUri)

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.

Parameters
`logoUri`	`Uri`

Returns
`Bitmap`

Throws
`IOException`