我有一个带片段的动作栏如下。我想使用“刷新”按钮操作栏菜单刷新当前片段。我看了很多使用getFragmentByTag（）的例子，但我的片段是动态创建的。我可以知道如何获取当前片段并刷新内容。
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
RssFragmentPagerAdapter mRssFragmentPagerAdapter;
ViewPager mViewPager;
List<RssCategory> categoryList;
// Database Helper
private DatabaseHelper db;
private ActionBar actionBar;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try{
db = DatabaseHelper.getInstance(getApplicationContext());
int categoryCount = db.getCategoriesCount();
// Create the adapter that will return a fragment for each of the three primary sections
// of the app.
mRssFragmentPagerAdapter = new RssFragmentPagerAdapter(getSupportFragmentManager(), categoryCount);
// Set up the action bar.
actionBar = getActionBar();
// Specify that the Home/Up button should not be enabled, since there is no hierarchical
// parent.
actionBar.setHomeButtonEnabled(false);
// Specify that we will be displaying tabs in the action bar.
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//actionBar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);
// Set up the ViewPager, attaching the adapter and setting up a listener for when the
// user swipes between sections.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mRssFragmentPagerAdapter);
mViewPager.setOffscreenPageLimit(categoryCount - 1);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// When swiping between different app sections, select the corresponding tab.
// We can also use ActionBar.Tab#select() to do this if we have a reference to the
// Tab.
actionBar.setSelectedNavigationItem(position);
}
});
initialiseActionBar();
}catch(Exception e){
Log.e(getClass().getName(), e.getMessage());
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
this.finish();
return true;
case R.id.action_refresh:
//TO REFRESH CURRENT Fragment
return true;
default:
return super.onOptionsItemSelected(item);
}
}
private void initialiseActionBar() {
if(categoryList == null)
categoryList = db.getAllCategories();
// For each of the sections in the app, add a tab to the action bar.
for (RssCategory category : categoryList) {
// Create a tab with text corresponding to the page title defined by the adapter.
// Also specify this Activity object, which implements the TabListener interface, as the
// listener for when this tab is selected.
actionBar.addTab(
actionBar.newTab()
.setText(category.getName())
.setTabListener(this));
}
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to one of the primary
* sections of the app.
*/
public static class RssFragmentPagerAdapter extends FragmentPagerAdapter {
private int pageCount;
public RssFragmentPagerAdapter(FragmentManager fm, int pageCount) {
super(fm);
this.pageCount = pageCount;
}
@Override
public Fragment getItem(int i) {
switch (i) {
default:
// The other sections of the app are dummy placeholders.
Fragment fragment = new RssFragment();
Bundle args = new Bundle();
args.putInt(RssFragment.ARG_CATEGORY_ID, i + 1);
fragment.setArguments(args);
return fragment;
}
}
@Override
public int getCount() {
return pageCount;
}
/*@Override
public CharSequence getPageTitle(int position) {
return "Section " + (position + 1);
}*/
}
/**
* A dummy fragment representing a section of the app, but that simply displays dummy text.
*/
public static class RssFragment extends Fragment {
public static final String ARG_CATEGORY_ID = "category_id";
View rootView;
private List<RssItem> resultList;
List<RssWebSite> websiteList;
ArrayList<String> urlList;
ProgressBar progressBar;
@SuppressWarnings("unchecked")
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
try{
rootView = inflater.inflate(R.layout.fragment_rss_items_list, container, false);
resultList = new ArrayList<RssItem>();
progressBar = (ProgressBar)rootView.findViewById(R.id.progressBar);
Bundle args = getArguments();
if(args != null){
DatabaseHelper db = DatabaseHelper.getInstance(rootView.getContext());
websiteList = db.getAllRssWebSiteByCategory(args.getInt(ARG_CATEGORY_ID));
urlList = new ArrayList<String>();
if(websiteList != null && websiteList.size() > 0){
for (RssWebSite website : websiteList) {
urlList.add(website.getRssUrl());
}
if(urlList.size() > 0) {
GetRSSDataTask task = new GetRSSDataTask();
task.execute(urlList);
}
}
}
}catch(Exception e){
Log.e(getClass().getName(), e.getMessage());
}
return rootView;
}
/**
* This class downloads and parses RSS Channel feed.
*
* @author clippertech
*
*/
private class GetRSSDataTask extends AsyncTask<ArrayList<String>, Void, List<RssItem> > {
@Override
protected List<RssItem> doInBackground(ArrayList<String>... urls) {
try {
for(String url : urls[0]) {
// Create RSS reader
RssReader rssReader = new RssReader(url);
Log.d(getClass().getName(), url);
// Parse RSS, get items
resultList.addAll(rssReader.getItems());
}
return resultList;
}catch (Exception e) {
Log.e(getClass().getName(), e.getMessage());
}
return null;
}
@Override
protected void onPostExecute(List<RssItem> result) {
try{
// Get a ListView from the RSS Channel view
ListView itcItems = (ListView) rootView.findViewById(R.id.rssChannelListView);
View emptyView = null;
if(result == null){
itcItems.setEmptyView(emptyView);
Log.d(getClass().getName(), "Empty View");
}
else {
//resultList.addAll(result);
Collections.sort(result, new Comparator<RssItem>() {
@Override
public int compare(RssItem lhs, RssItem rhs) {
SimpleDateFormat formatter = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz");
try {
Date date1 = formatter.parse(rhs.getPublishedDate());
Date date2 = formatter.parse(lhs.getPublishedDate());
return date1.compareTo(date2);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return 0;
}
});
// Create a list adapter
ListAdapter adapter = new ListAdapter(rootView.getContext(), resultList);
itcItems.setAdapter(adapter);
adapter.notifyDataSetChanged();
// Set list view item click listener
itcItems.setOnItemClickListener(new ListListener(resultList, getActivity()));
}
//dialog.dismiss();
progressBar.setVisibility(View.GONE);
}catch(Exception e){
Log.e(getClass().getName(), e.getMessage());
}
}
}
}
}
答案 0 :(得分：0)
您需要使用viewpager中的PageChangeListener跟踪当前片段索引。
您可以使用片段索引从适配器中检索片段，并调用您需要的任何方法。