我正在尝试在 ListFragment 上使用 setRetainInstance(true)，直到 onCreateView 它像一个魅力一样工作，类中的所有属性都被保留并且似乎没问题。但是一旦屏幕旋转并生成视图，listView 就不会显示，尽管适配器和数据在那里。
我想请你在这个主题上提供一些指导，因为它是我最好的。
我将粘贴活动、片段和布局的代码：
内容活动.java
public class ContentActivity extends SherlockFragmentActivity {
private final String LOG_TAG = ContentActivity.class.getName();
private ContentListFragment contentFragment = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// set the content layout
setContentView(R.layout.content);
if (savedInstanceState == null) {
// Creates the fragment for the ContentList
contentFragment = new ContentListFragment();
// Add the fragment to the 'content_container' FrameLayout
getSupportFragmentManager()
.beginTransaction()
.add(R.id.content_container, contentFragment,
getResources().getString(R.id.content_container))
.commit();
} else {
// If we're being restored from a previous state,
// then we don't need to do anything and should return or else
// we could end up with overlapping fragments.
contentFragment = (ContentListFragment) getSupportFragmentManager()
.findFragmentByTag(
getResources().getString(R.id.content_container));
}
}
}
这是 ContentActivity content.xml 的布局
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/content_container"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
这是 ContentListFragment.java
public class ContentListFragment extends SherlockListFragment implements
LoaderCallbacks<HTTPRequestLoader.RESTResponse> {
private final String LOG_TAG = ContentListFragment.class.getName();
private static final int LOADER_PREFERENCES = 0x1f;
private ContentListAdapter contentAdapter = null;
private List<Content> contents = new ArrayList<Content>();
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.content_list, container, false);
Log.i(LOG_TAG, "onCreateView");
contentAdapter = new ContentListAdapter(getActivity(),
R.layout.content_block_item, contents);
Log.i(LOG_TAG,
"savedInstanceState==null size of the adapter in onCreateView "
+ contentAdapter.getCount());
Log.i(LOG_TAG, "savedInstanceState==null size of the contents "
+ contents.size());
setListAdapter(contentAdapter);
contentAdapter.notifyDataSetChanged();
return v;
}
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setRetainInstance(true);
// If there is no data, prepare the loader. Either re-connect with an
// existing one,
// or start a new one.
getActivity().getSupportLoaderManager().initLoader(LOADER_PREFERENCES,
null, this);
Log.i(LOG_TAG, "onCreate");
}
@Override
public Loader<RESTResponse> onCreateLoader(int id, Bundle params) {
return ConnectionManager.getInstance().getPreferencesLoader(
getActivity(), params);
}
@Override
public void onLoadFinished(Loader<HTTPRequestLoader.RESTResponse> loader,
HTTPRequestLoader.RESTResponse data) {
int code = data.getCode();
String json = data.getData();
Log.i(LOG_TAG, "loaderFinished");
// Check to see if we got an HTTP 200 code and have some data.
if (code == 200 && !json.equals("")) {
contentAdapter.clear();
contents = ParserJson.getPreferencesFromJson(json);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) {
contentAdapter.addAll(contents);
} else {
for (Content content : contents) {
contentAdapter.add(content);
}
}
contentAdapter.notifyDataSetChanged();
} else {
// TODO: extract string
Toast.makeText(
getActivity(),
"Failed to load Preferences data. Check your internet settings.",
Toast.LENGTH_SHORT).show();
}
}
@Override
public void onLoaderReset(Loader<RESTResponse> loader) {
}
public void deselectItems() {
for (Content content : contents) {
for (Section section : content.getSections()) {
section.setSelected(false);
}
}
contentAdapter.notifyDataSetChanged();
}
}
这是 content_list.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="hello_world" />
<ListView
android:id="@id/android:list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@null" />
<FrameLayout
android:id="@+id/content_dialog"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
</FrameLayout>
</LinearLayout>
如您所见，我仅在检查 savedInstanceState 时创建片段，当片段创建时，它会执行加载程序并设置视图。一旦加载器完成加载，它就会毫无问题地更新视图。
一旦我旋转模拟器的屏幕，只显示 content_list.xml 中的“hello_world”。
我试图将适配器的配置移动到 onViewCreated ，但没有成功。