TV上的推荐内容
最后更新于:2022-04-01 01:42:47
> 编写:[awong1900](https://github.com/awong1900) - 原文:[http://developer.android.com/training/tv/discovery/recommendations.html](http://developer.android.com/training/tv/discovery/recommendations.html)
当操作TV时,用户通常喜欢使用最少的输入操作来找内容。许多用户的理想场景是,坐下,打开TV然后观看。用最少的步骤让用户观看他们的喜欢的内容是最好的方式。
安卓framework为了实现少交互而提供了主屏幕推荐栏。在设备第一次使用时候,内容推荐出现在TV主屏幕的第一栏。从你的应用程序的内容目录提供建议可以帮助把用户带回到你的应用程序。
![home-recommendations](https://docs.gechiui.com/gc-content/uploads/sites/kancloud/2015-07-28_55b724748bde1.png)
图1. 一个推荐栏的例子
这节课教你如何创建推荐和提供他们到安卓framework,这样用户能容易的发现和使用你的应用内容。这个讨论描述了一些代码,在[安卓Leanback示例代码](https://github.com/googlesamples/androidtv-Leanback)。
### 创建推荐服务
内容推荐是被后台处理创建。为了把你的应用去提供到推荐,创建一个周期性添加列表服务,从应用目录到系统推荐列表。
接下来的代码描绘了如何扩展[IntentService](http://developer.android.com/reference/android/app/IntentService.html)为你的应用创建推荐服务:
~~~
public class UpdateRecommendationsService extends IntentService {
private static final String TAG = "UpdateRecommendationsService";
private static final int MAX_RECOMMENDATIONS = 3;
public UpdateRecommendationsService() {
super("RecommendationService");
}
@Override
protected void onHandleIntent(Intent intent) {
Log.d(TAG, "Updating recommendation cards");
HashMap<String, List<Movie>> recommendations = VideoProvider.getMovieList();
if (recommendations == null) return;
int count = 0;
try {
RecommendationBuilder builder = new RecommendationBuilder()
.setContext(getApplicationContext())
.setSmallIcon(R.drawable.videos_by_google_icon);
for (Map.Entry<String, List<Movie>> entry : recommendations.entrySet()) {
for (Movie movie : entry.getValue()) {
Log.d(TAG, "Recommendation - " + movie.getTitle());
builder.setBackground(movie.getCardImageUrl())
.setId(count + 1)
.setPriority(MAX_RECOMMENDATIONS - count)
.setTitle(movie.getTitle())
.setDescription(getString(R.string.popular_header))
.setImage(movie.getCardImageUrl())
.setIntent(buildPendingIntent(movie))
.build();
if (++count >= MAX_RECOMMENDATIONS) {
break;
}
}
if (++count >= MAX_RECOMMENDATIONS) {
break;
}
}
} catch (IOException e) {
Log.e(TAG, "Unable to update recommendation", e);
}
}
private PendingIntent buildPendingIntent(Movie movie) {
Intent detailsIntent = new Intent(this, DetailsActivity.class);
detailsIntent.putExtra("Movie", movie);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
stackBuilder.addParentStack(DetailsActivity.class);
stackBuilder.addNextIntent(detailsIntent);
// Ensure a unique PendingIntents, otherwise all recommendations end up with the same
// PendingIntent
detailsIntent.setAction(Long.toString(movie.getId()));
PendingIntent intent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
return intent;
}
}
~~~
为了服务被系统意识到和运行,在应用manifest中注册它,接下来的代码片段展示了如何定义这个类的服务:
~~~
<manifest ... >
<application ... >
...
<service
android:name="com.example.android.tvleanback.UpdateRecommendationsService"
android:enabled="true" />
</application>
</manifest>
~~~
### 刷新推荐
基于用户的行为和数据来推荐,例如播放列表,喜爱列表和相关内容。当刷新推荐时,不仅仅是删除和重新加载他们,因为这样导致推荐出现在推荐栏的结尾。一旦一个内容项被播放,如一个影片,从推荐中[删除它](http://developer.android.com/guide/topics/ui/notifiers/notifications.html#Removing)。
应用的推荐被保存依据哪个应用提供他们。framework interleave应用推荐基于推荐质量,用户习惯的收集。最好的推荐使应用推荐更幸运的出现在列表前面。
### 创建推荐
一旦你的推荐服务开始运行,它必须创建推荐和送他们到安卓framework。Framework收到推荐作为[通知](http://developer.android.com/reference/android/app/Notification.html)对象。它用特定的模板并且标记为特定的目录。
### 设置值
去设置推荐卡片的UI元素,创建一个builder类用接下来的builder样式描述。首先,设置推荐卡片元素的值。
~~~
public class RecommendationBuilder {
...
public RecommendationBuilder setTitle(String title) {
mTitle = title;
return this;
}
public RecommendationBuilder setDescription(String description) {
mDescription = description;
return this;
}
public RecommendationBuilder setImage(String uri) {
mImageUri = uri;
return this;
}
public RecommendationBuilder setBackground(String uri) {
mBackgroundUri = uri;
return this;
}
...
~~~
### 创建通知
一旦你设置了值,然后去创建通知,从builder类分配值到通知,并且调用[NotificationCompat.Builder.build](http://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html#build())。
并且,确信调用[setLocalOnly()](http://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html#setLocalOnly(boolean)),这样[NotificationCompat.BigPictureStyle](http://developer.android.com/reference/android/support/v4/app/NotificationCompat.BigPictureStyle.html)通知不将显示在另一个设备。
接下来的代码示例展示了如何创建推荐。
~~~
public class RecommendationBuilder {
...
public Notification build() throws IOException {
...
Notification notification = new NotificationCompat.BigPictureStyle(
new NotificationCompat.Builder(mContext)
.setContentTitle(mTitle)
.setContentText(mDescription)
.setPriority(mPriority)
.setLocalOnly(true)
.setOngoing(true)
.setColor(mContext.getResources().getColor(R.color.fastlane_background))
.setCategory(Notification.CATEGORY_RECOMMENDATION)
.setLargeIcon(image)
.setSmallIcon(mSmallIcon)
.setContentIntent(mIntent)
.setExtras(extras))
.build();
return notification;
}
}
~~~
### 运行推荐服务
你的应用推荐服务必须周期性运行,原因是创建当前的推荐。去运行你的服务,创建一个类运行计时器和在周期间隔关联它。接下来的代码例子扩展了[BroadcastReceiver](http://developer.android.com/reference/android/content/BroadcastReceiver.html)类去开始每半小时的推荐服务的周期性执行:
~~~
public class BootupActivity extends BroadcastReceiver {
private static final String TAG = "BootupActivity";
private static final long INITIAL_DELAY = 5000;
@Override
public void onReceive(Context context, Intent intent) {
Log.d(TAG, "BootupActivity initiated");
if (intent.getAction().endsWith(Intent.ACTION_BOOT_COMPLETED)) {
scheduleRecommendationUpdate(context);
}
}
private void scheduleRecommendationUpdate(Context context) {
Log.d(TAG, "Scheduling recommendations update");
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
Intent recommendationIntent = new Intent(context, UpdateRecommendationsService.class);
PendingIntent alarmIntent = PendingIntent.getService(context, 0, recommendationIntent, 0);
alarmManager.setInexactRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,
INITIAL_DELAY,
AlarmManager.INTERVAL_HALF_HOUR,
alarmIntent);
}
}
~~~
这个[BroadcastReceiver](http://developer.android.com/reference/android/content/BroadcastReceiver.html)类的实现必须运行在TV设备启动后。 去完成这个,注册这个类在应用manifest的intet filter中,它监听设备启动完成。接下来的代码展示了如何添加这个配置到manifest。
~~~
<manifest ... >
<application ... >
<receiver android:name="com.example.android.tvleanback.BootupActivity"
android:enabled="true"
android:exported="false">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
</intent-filter>
</receiver>
</application>
</manifest>
~~~
> **Important**: 接收一个启动完成通知需要你的应用有[RECEIVE_BOOT_COMPLETED](http://developer.android.com/reference/android/Manifest.permission.html#RECEIVE_BOOT_COMPLETED)权限。更多信息,查看[ACTION_BOOT_COMPLETED](http://developer.android.com/reference/android/content/Intent.html#ACTION_BOOT_COMPLETED)。
在推荐服务类的[onHandleIntent()](http://developer.android.com/reference/android/app/IntentService.html#onHandleIntent(android.content.Intent))方法,提交推荐到管理器,如下:
~~~
Notification notification = notificationBuilder.build();
mNotificationManager.notify(id, notification);
~~~
[下一节: 使TV应用可搜索](#)