編寫:[huanglizhuo](https://github.com/huanglizhuo) - 原文:[http://developer.android.com/training/tv/playback/details.html](http://developer.android.com/training/tv/playback/details.html) 待認領進行編寫，有意向的小伙伴，可以直接修改對應的markdown文件，進行提交！ [ v17 leanback support library ](http://developer.android.com/tools/support-library/features.html#v17-leanback)庫提供的媒體瀏覽接口包含顯示附加媒體信息的類,比如描述和預覽,以及對項目的操作,比如購買或播放。 這節課討論如何為媒體項目的詳細信息創建 presenter 類，以及用戶選擇一個媒體項目時如何擴展[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)類來實現顯示媒體詳細信息視圖。 > **小貼士:** 這里的實現例子用的是包含[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)的附加[activity](# "An activity represents a single screen with a user interface.")。但也可以在同一個 [activity](# "An activity represents a single screen with a user interface.") 中用 fragment 轉換將[ BrowseFragment](http://developer.android.com/reference/android/support/v17/leanback/app/BrowseFragment.html)替換為[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html).更多關于fragment的信息請參考[Building a Dynamic UI with Fragments](http://developer.android.com/training/basics/fragments/fragment-ui.html#Replace) ### 創建詳細Presenter 在leanback庫提供的媒體瀏覽框架中,可以用presenter對象控制屏幕顯示數據,包括媒體詳細信息。[AbstractDetailsDescriptionPresenter ](http://developer.android.com/reference/android/support/v17/leanback/widget/AbstractDetailsDescriptionPresenter.html)類提供的框架幾乎是媒體項目詳細信息的完全繼承。你只需要實現[onBindDescription()]()方法,像下面這樣把數據信息和視圖綁定起來。 ~~~ public class DetailsDescriptionPresenter extends AbstractDetailsDescriptionPresenter { @Override protected void onBindDescription(ViewHolder viewHolder, Object itemData) { MyMediaItemDetails details = (MyMediaItemDetails) itemData; // In a production app, the itemData object contains the information // needed to display details for the media item: // viewHolder.getTitle().setText(details.getShortTitle()); // Here we provide static data for testing purposes: viewHolder.getTitle().setText(itemData.toString()); viewHolder.getSubtitle().setText("2014 Drama TV-14"); viewHolder.getBody().setText("Lorem ipsum dolor sit amet, consectetur " + "adipisicing elit, sed do eiusmod tempor incididunt ut labore " + " et dolore magna aliqua. Ut enim ad minim veniam, quis " + "nostrud exercitation ullamco laboris nisi ut aliquip ex ea " + "commodo consequat."); } } ~~~ ### 擴展詳細fragment 當使用[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)類顯示你的媒體項目詳細信息時,擴展該類并提供像預覽圖片,操作等附加內容。你也可以提供一系列的相關媒體信息。 下面的例子演示了怎樣用presenter類為媒體項目添加預覽圖片和操作。這個例子也演示了添加相關媒體行。 ~~~ public class MediaItemDetailsFragment extends DetailsFragment { private static final String TAG = "MediaItemDetailsFragment"; private ArrayObjectAdapter mRowsAdapter; @Override public void onCreate(Bundle savedInstanceState) { Log.i(TAG, "onCreate"); super.onCreate(savedInstanceState); buildDetails(); } private void buildDetails() { ClassPresenterSelector selector = new ClassPresenterSelector(); // Attach your media item details presenter to the row presenter: DetailsOverviewRowPresenter rowPresenter = new DetailsOverviewRowPresenter(new DetailsDescriptionPresenter()); selector.addClassPresenter(DetailsOverviewRow.class, rowPresenter); selector.addClassPresenter(ListRow.class, new ListRowPresenter()); mRowsAdapter = new ArrayObjectAdapter(selector); Resources res = getActivity().getResources(); DetailsOverviewRow detailsOverview = new DetailsOverviewRow( "Media Item Details"); // Add images and action buttons to the details view detailsOverview.setImageDrawable(res.getDrawable(R.drawable.jelly_beans)); detailsOverview.addAction(new Action(1, "Buy $9.99")); detailsOverview.addAction(new Action(2, "Rent $2.99")); mRowsAdapter.add(detailsOverview); // Add a Related items row ArrayObjectAdapter listRowAdapter = new ArrayObjectAdapter( new StringPresenter()); listRowAdapter.add("Media Item 1"); listRowAdapter.add("Media Item 2"); listRowAdapter.add("Media Item 3"); HeaderItem header = new HeaderItem(0, "Related Items", null); mRowsAdapter.add(new ListRow(header, listRowAdapter)); setAdapter(mRowsAdapter); } } ~~~ ### 創建詳細信息[activity](# "An activity represents a single screen with a user interface.") 像[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)這樣的 fragment 為了使用或顯示必須包含[activity](# "An activity represents a single screen with a user interface.")。為你的詳細信息與瀏覽分開創建[activity](# "An activity represents a single screen with a user interface.")并通過傳遞Intent打開。這節演示了如何創建一個包含媒體詳細信息的[activity](# "An activity represents a single screen with a user interface.")。 創建詳細信息前先為[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)創建一個布局文件: ~~~ <!-- file: res/layout/details.xml --> <fragment xmlns:android="http://schemas.android.com/apk/res/android" android:name="com.example.android.mediabrowser.MediaItemDetailsFragment" android:id="@+id/details_fragment" android:layout_width="match_parent" android:layout_height="match_parent" /> ~~~ 接下來用上面的布局文件創建一個[activity](# "An activity represents a single screen with a user interface."): ~~~ public class DetailsActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.details); } } ~~~ 最后在manifest文件中申明[activity](# "An activity represents a single screen with a user interface.")。記得添加Leanback主題以確保用戶界面中有媒體瀏覽[activity](# "An activity represents a single screen with a user interface.")。 ~~~ <application> ... <activity android:name=".DetailsActivity" android:exported="true" android:theme="@style/Theme.Leanback"/> </application> ~~~ ### 為點擊項目添加Listener 實現[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)后,在用戶點擊媒體條目時將你的媒體瀏覽view切換詳細信息view。為了確保動作的實現,在[BrowserFragment]()中添加[OnItemViewClickedListener]通過Intent開啟詳細信息[activity](# "An activity represents a single screen with a user interface.")。 下面的例子演示了實現怎樣在媒體瀏覽view中實現一個 listener開啟詳細信息view。 ~~~ public class BrowseMediaActivity extends Activity { ... @Override protected void onCreate(Bundle savedInstanceState) { ... // create the media item rows buildRowsAdapter(); // add a listener for selected items mBrowseFragment.OnItemViewClickedListener( new OnItemViewClickedListener() { @Override public void onItemClicked(Object item, Row row) { System.out.println("Media Item clicked: " + item.toString()); Intent intent = new Intent(BrowseMediaActivity.this, DetailsActivity.class); // pass the item information intent.getExtras().putLong("id", item.getId()); startActivity(intent); } }); } } ~~~