我正在开发一个使用 ActionBarSherlock 和 ViewPagerIndicator 的 Android 应用程序。主要活动是 SherlockFragmentActivity，用户通过操作栏上的选项卡在片段之间导航。所有选项卡都是 SherlockListFragments，并且大多数只包含一个 ListView。但是，一个片段 (HeadlinesFragment) 包含一个 ViewPager、CirclePageIndicator 和一个用于平板电脑的 ListView，而在手机上只有一个 ListView。ViewPager 有一个 FragmentStatePagerAdapter，它为项目返回一个 SherlockFragment。
问题是，在方向更改（或任何配置更改）时，ViewPager 内的子片段不会重新加载，并且 CirclePagerIndicator 不会显示任何指标，就好像 ViewPager 为空一样。但是，ListView 确实会正确重新加载。在片段的初始加载时，ViewPager 可以正常工作，但在方向改变之后就不行了。
MainActivity.java
public class MainActivity extends SherlockFragmentActivity {
// =============== Variable Declaration ================
private HashMap<Integer, String> tabData;
private HashMap<Integer, String> tabExtra;
private Fragment currentFragment = null;
private Fragment savedFragment = null;
public ActionBar mActionBar;
public MenuItem mRefresh;
public static int mCurrentPos;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
HashMap<String, Object> savedData = (HashMap<String, Object>) getLastCustomNonConfigurationInstance();
if (savedData != null) {
tabData = (HashMap<Integer, String>) savedData.get("tabData");
tabExtra = (HashMap<Integer, String>) savedData.get("tabExtra");
savedFragment = (Fragment) savedData.get("currentFragment");
mCurrentPos = ((Integer) savedData.get("pos")).intValue();
} else {
tabData = (HashMap<Integer, String>) getIntent().getExtras().getSerializable("tabData");
tabExtra = (HashMap<Integer, String>) getIntent().getExtras().getSerializable("tabExtra");
mCurrentPos = 0;
}
mActionBar = getSupportActionBar();
Const.IsTablet = Utils.isTablet(MainActivity.this);
//if (!Const.IsTablet) setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
TypedArray tabs = getResources().obtainTypedArray(R.array.TabBars);
Tab tab;
for (int i = 0; i < tabs.length(); i++) {
String tabInfo[] = getResources().getStringArray(tabs.getResourceId(i, 0));
tab = mActionBar.newTab().setText(tabInfo[1]);
if (tabInfo[0].equalsIgnoreCase("customizedNewsPage")) {
tab.setTabListener(new MainTabListener<HeadlinesFragment>(MainActivity.this, i, HeadlinesFragment.class));
}
mActionBar.addTab(tab);
}
tabs.recycle();
mActionBar.selectTab(mActionBar.getTabAt(mCurrentPos));
mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//set navbar for ICS+ devices
mActionBar.setBackgroundDrawable(getResources().getDrawable(R.drawable.navbar));
}
@SuppressLint("HandlerLeak")
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message message) {
Bundle bundle = message.getData();
if (bundle.getInt("result") == Activity.RESULT_OK && bundle.getString("data") != null) {
tabData.put(Integer.valueOf(bundle.getInt("tabPos")), bundle.getString("data"));
DataType type = DataType.values()[bundle.getInt("type")];
switch (type) {
case Headlines:
((HeadlinesFragment) currentFragment).setData(bundle.getString("data"));
break;
}
tabData.put(Integer.valueOf(bundle.getInt("tabPos")), bundle.getString("data"));
setRefreshActionButtonState(false);
}
}
};
public Handler getHandler() {
return mHandler;
}
@Override
public Object onRetainCustomNonConfigurationInstance() {
final HashMap<String, Object> savedData = new HashMap<String, Object>();
savedData.put("currentFragment", currentFragment);
savedData.put("tabData", tabData);
savedData.put("tabExtra", tabExtra);
savedData.put("pos", Integer.valueOf(mCurrentPos));
return savedData;
}
private class MainTabListener<T extends Fragment> implements TabListener {
private Fragment mFragment;
private final SherlockFragmentActivity mActivity;
private final int mPos;
private final Class<T> mClass;
/** Constructor used each time a new tab is created. */
public MainTabListener(SherlockFragmentActivity activity, int pos, Class<T> clz) {
mActivity = activity;
mPos = pos;
mClass = clz;
}
@Override
public void onTabSelected(Tab tab, FragmentTransaction ignoredFt) {
FragmentManager fragMgr = ((FragmentActivity) mActivity).getSupportFragmentManager();
FragmentTransaction ft = fragMgr.beginTransaction();
// Check if the fragment is already initialized
if (mFragment == null) {
// If not, instantiate and add it to the activity
mFragment = Fragment.instantiate(mActivity, mClass.getName());
Bundle args = new Bundle();
args.putString("data", tabData.get(mPos));
args.putInt("pos", mPos);
mFragment.setArguments(args);
ft.add(android.R.id.content, mFragment);
} else {
ft.attach(mFragment);
}
currentFragment = mFragment;
mCurrentPos = mPos;
mRefresh = null;
ft.commit();
}
@Override
public void onTabUnselected(Tab tab, FragmentTransaction ignoredFt) {
FragmentManager fragMgr = ((FragmentActivity) mActivity).getSupportFragmentManager();
FragmentTransaction ft = fragMgr.beginTransaction();
fragMgr.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
// Check if the fragment is already initialized
if (mFragment == null) {
mFragment = SherlockFragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment);
} else {
ft.detach(mFragment);
}
currentFragment = null;
ft.commit();
}
@Override
public void onTabReselected(Tab tab, FragmentTransaction ignoredFt) {
onTabUnselected(tab, ignoredFt);
onTabSelected(tab, ignoredFt);
}
}
}
头条新闻Fragment.java
public class HeadlinesFragment extends SherlockListFragment implements SearchView.OnQueryTextListener, SearchView.SearchViewChangeMode, OnItemClickListener {
private static final String LOG_TAG = "Headlines Fragment";
private JSONArray mHeadlines = new JSONArray();
private JSONArray mHeadlinesTop = new JSONArray();
private SearchView mSearchView;
private MenuItem mSearchItem;
private ViewPager mPager;
private CirclePageIndicator mIndicator;
private static int mPos;
private int mRotatorImageWidth;
private static HeadlinesFragment instance;
private Tracker tracker;
private Timer refreshTimer;
private int refreshTime = 0;;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
instance = this;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mPos = getArguments().getInt("pos");
TypedArray tabs = getResources().obtainTypedArray(R.array.TabBars);
String tabInfo[] = getResources().getStringArray(tabs.getResourceId(mPos, 0));
mRotatorImageWidth = Integer.valueOf(tabInfo[7]).intValue();
refreshTime = Integer.valueOf(tabInfo[4]).intValue();
tabs.recycle();
try {
mHeadlines = new JSONArray(getArguments().getString("data"));
} catch (NotFoundException e) {
Log.e(LOG_TAG, "Error loading data", e);
} catch (JSONException e) {
Log.e(LOG_TAG, "Error loading data", e);
}
return inflater.inflate(R.layout.activity_headlines, container, false);
}
@SuppressWarnings("deprecation")
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//if (Const.IsTablet) {
if (((SIDHelpApplication) getActivity().getApplicationContext()).isTablet()) {
try {
mHeadlinesTop = new JSONArray();
JSONArray temp = new JSONArray();
for (int i = 0; i < mHeadlines.length(); i++) {
if (i < 5) {
mHeadlinesTop.put(mHeadlines.get(i));
} else {
temp.put(mHeadlines.get(i));
}
}
mHeadlines = temp;
} catch (JSONException e) {
Log.e(LOG_TAG, "Error splitting off top 5", e);
}
mPager = (ViewPager) getActivity().findViewById(R.id.rotator);
mPager.setOffscreenPageLimit(4);
mPager.setAdapter(new RotatorAdapter(this, getActivity(), mHeadlinesTop, mRotatorImageWidth, mPos));
if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
mPager.getLayoutParams().height = (int) Math.floor((((float) getResources().getInteger(R.integer.NewsImageHeight) / (float) getResources().getInteger(R.integer.NewsImageWidth)) * (float) getActivity().getWindowManager().getDefaultDisplay().getWidth()));
}
mIndicator = (CirclePageIndicator) getActivity().findViewById(R.id.indicator);
mIndicator.setViewPager(mPager);
}
setListAdapter(new HeadlinesAdapter(getSherlockActivity(), mHeadlines));
getListView().setOnItemClickListener(this);
getListView().setEmptyView(getActivity().findViewById(android.R.id.empty));
setAutoRefresh();
}
public void setData(String data) {
setData(data, false);
}
public void setData(String data, boolean search) {
try {
mHeadlines = new JSONArray(data);
if (((SIDHelpApplication) getActivity().getApplicationContext()).isTablet() && !search) {
mHeadlinesTop = new JSONArray();
try {
JSONArray temp = new JSONArray();
for (int i = 0; i < mHeadlines.length(); i++) {
if (i < 5) {
mHeadlinesTop.put(mHeadlines.get(i));
} else {
temp.put(mHeadlines.get(i));
}
}
mHeadlines = temp;
} catch (JSONException e) {
Log.e(LOG_TAG, "Error splitting off top 5", e);
}
((RotatorAdapter) mPager.getAdapter()).setData(mHeadlinesTop);
mPager.setVisibility(View.VISIBLE);
mIndicator.setVisibility(View.VISIBLE);
} else {
getActivity().findViewById(android.R.id.empty).setVisibility(View.GONE);
}
if (search && mPager != null) {
mPager.setVisibility(View.GONE);
mIndicator.setVisibility(View.GONE);
}
((HeadlinesAdapter) getListAdapter()).setData(mHeadlines);
setAutoRefresh();
} catch (JSONException e) {
Log.e(LOG_TAG, "Setting Data", e);
}
}
public static HeadlinesFragment getInstance() {
return instance;
}
}
活动标题.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/llMainHeadline"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="false"
android:focusableInTouchMode="true"
android:background="@drawable/bg_img" >
<android.support.v4.view.ViewPager
android:id="@+id/rotator"
android:layout_width="match_parent"
android:layout_height="@dimen/headlines_rotator_height"
android:layout_alignParentTop="true"
android:background="@android:color/black" />
<com.viewpagerindicator.CirclePageIndicator
android:id="@+id/indicator"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/rotator"
android:background="@android:color/black"
android:padding="10dp" />
<ListView
android:id="@android:id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentBottom="true"
android:layout_below="@id/indicator"
android:cacheColorHint="#00000000"
android:listSelector="@color/TableCellSelection" />
<TextView
android:id="@android:id/empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="@string/noResults"
android:textSize="@dimen/noResult_text_size"
android:textStyle="bold"
android:visibility="gone" />
</RelativeLayout>
RotatorAdapter.java
public class RotatorAdapter extends FragmentStatePagerAdapter {
private static final String LOG_TAG = "Rotator Adapter";
private Context mContext;
private JSONArray mData;
private int mImageWidth;
private int mPos;
public RotatorAdapter(SherlockListFragment fragment, Context context, JSONArray data, int imageWidth, int pos) {
super(fragment.getChildFragmentManager());
mContext = context;
mData = data;
mImageWidth = imageWidth;
mPos = pos;
}
@Override
public int getCount() {
return mData.length();
}
@Override
public Fragment getItem(int pos) {
Fragment fragment = null;
Bundle args = new Bundle();
try {
JSONObject hdata = mData.getJSONObject(pos);
args.putString("title", hdata.getString(mContext.getResources().getString(R.string.tag_title)));
args.putString("category", hdata.getString(mContext.getResources().getString(R.string.tag_category)));
args.putString("time", hdata.getString(mContext.getResources().getString(R.string.tag_time)));
args.putString("newsID", hdata.getString(mContext.getResources().getString(R.string.tag_newsID)));
args.putString("photoURL", hdata.getString(mContext.getResources().getString(R.string.tag_photoURL)));
args.putInt("imageWidth", mImageWidth);
args.putInt("pos", mPos);
fragment = Fragment.instantiate(mContext, RotatorFragment.class.getName(), args);
} catch (JSONException e) {
Log.e(LOG_TAG, "Error getting data", e);
}
return fragment;
}
public void setData(JSONArray data) {
mData = data;
notifyDataSetChanged();
}
}
RotatorFragment.java
public class RotatorFragment extends SherlockFragment implements OnClickListener {
private static final String LOG_TAG = "Rotator Fragment";
private String mNewsID;
private int mPos;
private ImageLoader imageLoader = ImageLoader.getInstance();
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_headlines_top_row, container, false);
// Set the image
ImageView image = (ImageView) view.findViewById(R.id.imgArticle);
String photoURL = getArguments().getString("photoURL").replaceAll(" ", "%20");
imageLoader.displayImage(photoURL, image);
// Set title, category, and time
TextView headlineTitle = (TextView) view.findViewById(R.id.txtTitle);
TextView headlineCategory = (TextView) view.findViewById(R.id.txtCategory);
headlineTitle.setText(getArguments().getString("title"));
headlineCategory.setText(String.format("%s - %s", getArguments().getString("category"), getArguments().getString("time")));
// Set article ID for onclick listener
mNewsID = getArguments().getString("newsID");
mPos = getArguments().getInt("pos");
view.setOnClickListener(this);
return view;
}
@Override
public void onClick(View v) {
// Load article data
Log.i(LOG_TAG, "Loading Article");
Intent dataIntent = new Intent(getActivity(), DataLoader.class);
Messenger dataMessenger = new Messenger(HeadlinesFragment.mHandler);
dataIntent.putExtra("MESSENGER", dataMessenger);
dataIntent.putExtra("tabPos", mPos);
dataIntent.putExtra("type", DataType.HeadlinesArticle.ordinal());
String params[] = new String[] {mNewsID};
dataIntent.putExtra("params", params);
getActivity().startService(dataIntent);
}
@Override
public void onSaveInstanceState (Bundle outState) {
// Don't save the fragment state
}
}