Android操作欄選項卡：屏幕旋轉

嗨我遇到操作欄和使用ABS的選項卡問題。我有兩個選項卡，第一個選項卡，「收藏夾」，只是延伸Fragment，並沒有顯示任何內容。第二個「行」擴展了SherlockListFragment並實現了LoaderManager.LoaderCallbacks（從數據庫加載用戶列表）。Android操作欄選項卡：屏幕旋轉

該應用程序工作正常（或者至少，我認爲是這樣），但是當我旋轉屏幕時出現問題。如果我選擇了LinesTab（顯示列表）並處於縱向模式，然後切換到橫向，則FavouritesTab的內容（最初爲空）將填充LinesTab的內容。

這是代碼的重要部分。

Main.java（創建兩個標籤）

public class Main extends SherlockFragmentActivity { 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    ActionBar actionBar = getSupportActionBar(); 
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 
    actionBar.setDisplayShowTitleEnabled(true); 

    Tab tab = actionBar 
      .newTab() 
      .setText("Favourites") 
      .setTabListener(new FavouritesTab()); 
    actionBar.addTab(tab); 

    tab = actionBar 
      .newTab() 
      .setText("Lines") 
      .setTabListener(new LinesTab()); 
    actionBar.addTab(tab); 
    } 
}

LinesTab.java（即使用LoaderManager加載用戶數據庫的選項卡）

public class LinesTab extends SherlockListFragment implements ActionBar.TabListener, 
    LoaderManager.LoaderCallbacks<ArrayList<User>> { 
UserAdapter adapter; 
Database db; 

public void onCreate(Bundle savedInstanceState) { 
    adapter = new UserAdapter(getActivity(), new ArrayList<User>()); 
    setListAdapter(adapter); 
    getActivity().getSupportLoaderManager().initLoader(0, null, this); 
    super.onCreate(savedInstanceState); 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle state) { 
    return super.onCreateView(inflater, container, state); 
} 

@Override 
public void onActivityCreated(Bundle state) { 
    super.onActivityCreated(state); 
} 

// TabListener callbacks 
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) { 
    ft.add(android.R.id.content, this, "LinesTabTag"); 
    ft.attach(this); 
} 

public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) { 
    ft.detach(this); 
} 

public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {} 

// LoaderCallbacks 
@Override 
public Loader<ArrayList<User>> onCreateLoader(int id, Bundle args) { 
    db = new Database(getActivity()); 
    return new UserLoader(getActivity(), db); 
} 

@Override 
public void onLoadFinished(Loader<ArrayList<User>> loader, 
          ArrayList<User> usuarios) { 
    ((UserAdapter) getListAdapter()).update(usuarios); 
    ((UserAdapter) getListAdapter()).notifyDataSetChanged(); 
} 

@Override 
public void onLoaderReset(Loader<ArrayList<User>> loader) { 
    setListAdapter(null); 
} 
}

FavouritesTab.java（其他選項卡，不顯示任何東西）

public class FavouritesTab extends Fragment implements ActionBar.TabListener { 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle state) { 
    return super.onCreateView(inflater, container, state); 
} 

// TabListener callbacks 
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) { 
    ft.add(android.R.id.content, this, "LinesTabTag"); 
    ft.attach(this); 
} 

public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) { 
    ft.detach(this); 
} 

public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {} 
}

此外，我不太相當確定是否所有代碼都以正確的方式實現。具體爲onTabSelected方法。在Android documentation他們實現了一個監聽器來管理所有的片段，但我在每個片段中都實現了一個監聽器。所以我不知道ft.add然後ft.attach是實現該方法的最佳方式。

謝謝。

來源

2013-07-11 Enrique Marcos

最後我找到了解決方案。我實現了在Main.java一般TabListener並保存當前選項卡索引每次屏幕旋轉：和

Main.java

public class Main extends SherlockFragmentActivity { 
int pos = 0; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    ActionBar actionBar = getSupportActionBar(); 
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 
    actionBar.setDisplayShowTitleEnabled(true); 

    if (savedInstanceState != null) { 
     // Restore the last tab position 
     pos = savedInstanceState.getInt("pos"); 
    } 

    Tab tab = actionBar 
      .newTab() 
      .setText("Favourites") 
      .setTabListener(new TabListener<FavouritesTab>(this, "Favourites", FavouritesTab.class)); 
      //.setTabListener(new FavouritesTab()); 
    actionBar.addTab(tab); 

    tab = actionBar 
      .newTab() 
      .setText("Lines") 
      .setTabListener(new TabListener<LinesTab>(this, "LinesTab", LinesTab.class)); 
      //.setTabListener(new LinesTab()); 
    actionBar.addTab(tab); 

    // Set the last tab position, or zero by default 
    getSupportActionBar().setSelectedNavigationItem(pos); 
} 

@Override 
protected void onSaveInstanceState(Bundle outState) { 
    // Save the current tab position 
    super.onSaveInstanceState(outState); 
    outState.putInt("pos", getSupportActionBar().getSelectedNavigationIndex()); 
} 

// The TabListener 
static class TabListener<T extends Fragment> implements ActionBar.TabListener { 
    private Fragment mFragment; 
    private SherlockFragmentActivity mActivity; 
    private String mTag; 
    private Class<T> mClass; 

    public TabListener(SherlockFragmentActivity activity, String tag, Class<T> clz) { 
     mActivity = activity; 
     mTag = tag; 
     mClass = clz; 
    } 

    public void onTabSelected(Tab tab, FragmentTransaction ft) { 
     // 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()); 
      ft.add(android.R.id.content, mFragment, mTag); 
     } else { 
      // If it exists, simply attach it on order to show it 
      ft.attach(mFragment); 
     } 
    } 

    public void onTabUnselected(Tab tab, FragmentTransaction ft) { 
     if (mFragment != null) { 
      ft.detach(mFragment); 
     } 
    } 

    public void onTabReselected(Tab tab, FragmentTransaction ft) {} 
} 
}

我在LinesTab.java刪除裝載機回調FavouritesTab.java

來源

2013-07-14 17:00:29

偉大的答案！！ – Hevski

Android操作欄選項卡：屏幕旋轉

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