创建详情页
最后更新于：2022-04-01 01:42:40
编写:[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)
待认领进行编写，有意向的小伙伴，可以直接修改对应的markdown文件，进行提交！
[ v17 leanback support library ](http://developer.android.com/tools/support-library/features.html#v17-leanback)库提供的媒体浏览接口包含显示附加媒体信息的类,比如描述和预览,以及对项目的操作,比如购买或播放。
这节课讨论如何为媒体项目的详细信息创建 presenter 类，以及用户选择一个媒体项目时如何扩展[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)类来实现显示媒体详细信息视图。
> **小贴士:** 这里的实现例子用的是包含[ 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.")。但也可以在同一个 [activity](# "An activity represents a single screen with a user interface.") 中用 fragment 转换将[ BrowseFragment](http://developer.android.com/reference/android/support/v17/leanback/app/BrowseFragment.html)替换为[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html).更多关于fragment的信息请参考[Building a Dynamic UI with Fragments](http://developer.android.com/training/basics/fragments/fragment-ui.html#Replace)
### 创建详细Presenter
在leanback库提供的媒体浏览框架中,可以用presenter对象控制屏幕显示数据,包括媒体详细信息。[AbstractDetailsDescriptionPresenter ](http://developer.android.com/reference/android/support/v17/leanback/widget/AbstractDetailsDescriptionPresenter.html)类提供的框架几乎是媒体项目详细信息的完全继承。你只需要实现[onBindDescription()]()方法,像下面这样把数据信息和视图绑定起来。
~~~
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.");
}
}
~~~
### 扩展详细fragment
当使用[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)类显示你的媒体项目详细信息时,扩展该类并提供像预览图片,操作等附加内容。你也可以提供一系列的相关媒体信息。
下面的例子演示了怎样用presenter类为媒体项目添加预览图片和操作。这个例子也演示了添加相关媒体行。
~~~
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);
}
}
~~~
### 创建详细信息[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)这样的 fragment 为了使用或显示必须包含[activity](# "An activity represents a single screen with a user interface.")。为你的详细信息与浏览分开创建[activity](# "An activity represents a single screen with a user interface.")并通过传递Intent打开。这节演示了如何创建一个包含媒体详细信息的[activity](# "An activity represents a single screen with a user interface.")。
创建详细信息前先为[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)创建一个布局文件:
~~~
<!-- 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"
/>
~~~
接下来用上面的布局文件创建一个[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.")。记得添加Leanback主题以确保用户界面中有媒体浏览[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>
~~~
### 为点击项目添加Listener
实现[ DetailsFragment](http://developer.android.com/reference/android/support/v17/leanback/app/DetailsFragment.html)后,在用户点击媒体条目时将你的媒体浏览view切换详细信息view。为了确保动作的实现,在[BrowserFragment]()中添加[OnItemViewClickedListener]通过Intent开启详细信息[activity](# "An activity represents a single screen with a user interface.")。
下面的例子演示了实现怎样在媒体浏览view中实现一个 listener开启详细信息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);
}
});
}
}
~~~