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我在ViewPager中有4個片段與TabLayout集成。這些碎片中的每一個都有一個RecyclerView，因爲我顯示的是未知數量的列表項。這些項目是按日期加載的，所以我有兩個按鈕可讓您更改日期，然後根據設置的日期加載列表項目中的相應數據。按鈕是外部活動的一部分。ViewPager中的片段在其RecyclerView中不顯示任何東西
到目前爲止的一切都很完美，但是一旦我旋轉設備，碎片不會加載任何東西。碎片內沒有顯示任何內容。雖然外部活動的視圖顯示得很好。奇怪的是，如果我觸摸其中一個更改日期的按鈕，則會加載碎片並正確顯示數據。但是我需要在旋轉後立即顯示所有內容，而不僅僅是當我點擊其中一個按鈕時。這裏是我的代碼：
public class MainActivity extends AppCompatActivity implements DatePickerFragment.DateDialogInterface
{
private final static String COLOR_CONTROL_CHOSEN = "color_control_chosen";
private static final String DIALOG_DATE = "dialog_date";
private static final String TAG = "MainActivity";
private static final String SET_LOCATION = "set_location";
public static final String LEAGUE_POSITION = "league_position";
private Toolbar mToolbar;
private ViewPager mViewPager;
private TabLayout mTabLayout;
private ImageButton mPrevDateButton, mNextDateButton;
private TextView mDateTextView, mLeagueTextView;
private String mTodaysDate;
private Date mLastSelectedDate, mTodaysDateObj;
private ProgressBar mProgressBar;
private FragmentPagerAdapter mAdapterViewPager;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mToolbar = (Toolbar) findViewById(R.id.outnix_toolbar);
mViewPager = (ViewPager) findViewById(R.id.main_activity_view_pager);
mTabLayout = (TabLayout) findViewById(R.id.main_activity_tab_layout);
mDateTextView = (TextView) findViewById(R.id.display_date_text_view);
mLeagueTextView = (TextView) findViewById(R.id.league_title_header);
mPrevDateButton = (ImageButton) findViewById(R.id.previous_date_button);
mNextDateButton = (ImageButton) findViewById(R.id.next_date_button);
mProgressBar = (ProgressBar) findViewById(R.id.loading_circle);
mProgressBar.setVisibility(View.GONE);
setTodaysDate();
mDateTextView.setText("Today");
setSupportActionBar(mToolbar);
assert getSupportActionBar() != null;
getSupportActionBar().setDisplayShowTitleEnabled(false);
NavDrawerFragment navDrawerFrag = (NavDrawerFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_nav_drawer);
navDrawerFrag.setUp((DrawerLayout) findViewById(R.id.nav_drawer), mToolbar);
setUpViewPagerAdapterOnCreate();
mTabLayout.setupWithViewPager(mViewPager);
mDateTextView.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
FragmentManager fm = getSupportFragmentManager();
DatePickerFragment dialog = new DatePickerFragment();
Bundle args = new Bundle();
args.putSerializable("ARG_DATE", mLastSelectedDate);
dialog.setArguments(args);
dialog.show(fm, DIALOG_DATE);
}
});
THESE TWO LISTENERS ARE WHAT DISPLAY THE DATA AFTER A ROTATION CHANGE
//////////////////////////////////////////////////////////////////
mPrevDateButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
mProgressBar.setVisibility(View.VISIBLE);
updateDate(-1);
setupViewPagerAdapter(getViewPagerPos());
}
});
mNextDateButton.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
mProgressBar.setVisibility(View.VISIBLE);
updateDate(1);
setupViewPagerAdapter(getViewPagerPos());
}
});
}
////////////////////////////////////////////////////////////////////
/* @Override
protected void onResume()
{
super.onResume();
setupViewPagerAdapter(getViewPagerPos());
}*/
private void setUpViewPagerAdapterOnCreate() //only called when opened from LauncherActivity
{
setupViewPagerAdapter(0);
int touchColorPixel = getIntent().getIntExtra(COLOR_CONTROL_CHOSEN, ContextCompat.getColor(this, R.color.blue));
if(touchColorPixel == ContextCompat.getColor(this, R.color.orange))
mViewPager.setCurrentItem(0);
else if(touchColorPixel == ContextCompat.getColor(this, R.color.blue))
mViewPager.setCurrentItem(1);
else
mViewPager.setCurrentItem(3);
}
private void setupViewPagerAdapter(int currentPos)
{
mAdapterViewPager = new MainPagerAdapter(getSupportFragmentManager());
mViewPager.setAdapter(mAdapterViewPager);
mViewPager.setOffscreenPageLimit(4);
mViewPager.setCurrentItem(currentPos);
}
@Override
protected void onSaveInstanceState(Bundle outState)
{
super.onSaveInstanceState(outState);
outState.putSerializable(DIALOG_DATE, mLastSelectedDate); //save the last date selected (or last date displayed) on rotation change.
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
{
super.onRestoreInstanceState(savedInstanceState);
setDateFromDialog((Date) savedInstanceState.getSerializable(DIALOG_DATE)); //restore the last date selected to the new rotation change
}
public ProgressBar getProgressBar()
{
return mProgressBar;
}
@Override
public void setDateFromDialog(Date date)
{
String newDate = getFormattedDate(date);
updateTodaysDate();
mLastSelectedDate = date;
setupViewPagerAdapter(getViewPagerPos());
if(newDate.equals(mTodaysDate))
mDateTextView.setText("Today");
else
mDateTextView.setText(newDate);
}
private int getViewPagerPos()
{
return mViewPager.getCurrentItem();
}
}
的2個按鈕mPrevDateButton和mNextDateButton是當點擊「修復」的問題的按鈕。在他們的點擊監聽器中，updateDate()方法只做與TextView對象相關的東西，這就是爲什麼我沒有包含定義（我試圖儘可能縮短髮布時間）。所以我肯定知道它與我的setupViewPagerAdapter()方法有關。我已經嘗試在onCreate()和onResume()中添加此方法，但片段仍然保持空白。
這裏是我的ViewPager適配器代碼：
public class MainPagerAdapter extends FragmentPagerAdapter
{
private final String[] mFragmentTitleList = {"My Games", "All Games", "All Places", "My Places"}; //tab title names
private final static int NUM_FRAGMENTS = 4;
public MainPagerAdapter(FragmentManager fm)
{
super(fm);
}
@Override
public Fragment getItem(int position)
{
switch(position)
{
case 0:
return MyGamesFragment.newInstance();
case 1:
return AllGamesFragment.newInstance();
case 2:
return AllPlacesFragment.newInstance();
case 3:
return MyPlacesFragment.newInstance();
default:
return null;
}
}
@Override
public int getCount()
{
return NUM_FRAGMENTS;
}
@Override
public CharSequence getPageTitle(int position)
{
return mFragmentTitleList[position];
}
}
這裏是4個片段之一。他們幾乎都有類似的設計。
public class AllGamesFragment extends Fragment
{
private SwipeRefreshLayout mSwipeRefreshLayout;
private RecyclerView mAllGamesRecyclerView;
private GameAdapter mGameAdapter;
private List<Game> mGameList = new ArrayList<>();
private MainActivity mMainActivity; //keeps a reference to MainActivity to access public methods
public static AllGamesFragment newInstance()
{
return new AllGamesFragment();
}
@Override
public void onAttach(Context context)
{
super.onAttach(context);
mMainActivity = (MainActivity) context;
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setRetainInstance(true);
mMainActivity.getProgressBar().setVisibility(View.VISIBLE);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.recycler_view_all_games, container, false);
mAllGamesRecyclerView = (RecyclerView) view.findViewById(R.id.all_games_recycler_view);
mAllGamesRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
mSwipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipe_refresh);
mSwipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener()
{
@Override
public void onRefresh()
{
getGamesData();
mSwipeRefreshLayout.setRefreshing(false);
}
});
return view;
}
@Override
public void onResume()
{
super.onResume();
getGamesData();
}
private void setupAdapter()
{
if(isAdded())
{
mGameAdapter = new GameAdapter(mGameList);
mAllGamesRecyclerView.setAdapter(mGameAdapter);
}
}
private void getGamesData()
{
new GetDataTask(mMainActivity.getLastSelectedDate()).execute();
}
private class GetDataTask extends Scraper.GameDataTask
{
GetDataTask(Date date)
{
super(date, getActivity());
}
@Override
protected void onPostExecute(List<Game> games)
{
mGameList = games;
setupAdapter();
mMainActivity.getProgressBar().setVisibility(View.GONE);
}
}
private class GameAdapter extends RecyclerView.Adapter<GameHolder>
{
private List<Game> mGames;
public GameAdapter(List<Game> games)
{
mGames = games;
}
@Override
public GameHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
LayoutInflater inflater = LayoutInflater.from(getActivity());
View view = inflater.inflate(R.layout.list_game_item, parent, false);
return new GameHolder(view, getActivity());
}
@Override
public void onBindViewHolder(GameHolder holder, int position)
{
holder.bindGameData(mGames.get(position));
}
@Override
public int getItemCount()
{
return mGames.size();
}
}
我已經看過這麼多的帖子在這裏，多次改變了我的代碼，我仍然無法得到它的工作。當我點擊其中一個日期按鈕時，我感到困惑，它「修復了」。如果你想讓我發佈更多的代碼讓我知道。對不起，對於長篇文章，但我覺得上下文是必要的。我非常感謝任何幫助！
你聲明並初始化的地方是isAdded（） –
@HRaval是一個片段的內置函數，用於檢查它是否附加到一個活動。 –
嘗試[這]（http://stackoverflow.com/a/17629575/3117966），希望它會有所幫助 – Nisarg