從活動到片段的字符串轉移

Question

我在視圖尋呼機的文檔中看到了此代碼。我想從我的活動傳遞一個字符串到一個片段類。我想我可以使用捆綁參數傳遞它。我如何在我的片段類中訪問它？也有人可以解釋爲什麼我們在這裏擴展片段活動？

public class ActionBarTabsPager extends Activity { 
ViewPager mViewPager; 
TabsAdapter mTabsAdapter; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    mViewPager = new ViewPager(this); 
    mViewPager.setId(R.id.pager); 
    setContentView(mViewPager); 

    final ActionBar bar = getActionBar(); 
    bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 
    bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE); 

    mTabsAdapter = new TabsAdapter(this, mViewPager); 
    mTabsAdapter.addTab(bar.newTab().setText("Simple"), 
      CountingFragment.class, null); 
    mTabsAdapter.addTab(bar.newTab().setText("List"), 
      FragmentPagerSupport.ArrayListFragment.class, null); 
    mTabsAdapter.addTab(bar.newTab().setText("Cursor"), 
      CursorFragment.class, null); 

    if (savedInstanceState != null) { 
     bar.setSelectedNavigationItem(savedInstanceState.getInt("tab", 0)); 
    } 
} 

@Override 
protected void onSaveInstanceState(Bundle outState) { 
    super.onSaveInstanceState(outState); 
    outState.putInt("tab", getActionBar().getSelectedNavigationIndex()); 
} 

/** 
* This is a helper class that implements the management of tabs and all 
* details of connecting a ViewPager with associated TabHost. It relies on a 
* trick. Normally a tab host has a simple API for supplying a View or 
* Intent that each tab will show. This is not sufficient for switching 
* between pages. So instead we make the content part of the tab host 
* 0dp high (it is not shown) and the TabsAdapter supplies its own dummy 
* view to show as the tab content. It listens to changes in tabs, and takes 
* care of switch to the correct paged in the ViewPager whenever the selected 
* tab changes. 
*/ 
public static class TabsAdapter extends FragmentPagerAdapter 
     implements ActionBar.TabListener, ViewPager.OnPageChangeListener { 
    private final Context mContext; 
    private final ActionBar mActionBar; 
    private final ViewPager mViewPager; 
    private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>(); 

    static final class TabInfo { 
     private final Class<?> clss; 
     private final Bundle args; 

     TabInfo(Class<?> _class, Bundle _args) { 
      clss = _class; 
      args = _args; 
     } 
    } 

    public TabsAdapter(Activity activity, ViewPager pager) { 
     super(activity.getFragmentManager()); 
     mContext = activity; 
     mActionBar = activity.getActionBar(); 
     mViewPager = pager; 
     mViewPager.setAdapter(this); 
     mViewPager.setOnPageChangeListener(this); 
    } 

    public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) { 
     TabInfo info = new TabInfo(clss, args); 
     tab.setTag(info); 
     tab.setTabListener(this); 
     mTabs.add(info); 
     mActionBar.addTab(tab); 
     notifyDataSetChanged(); 
    } 

    @Override 
    public int getCount() { 
     return mTabs.size(); 
    } 

    @Override 
    public Fragment getItem(int position) { 
     TabInfo info = mTabs.get(position); 
     return Fragment.instantiate(mContext, info.clss.getName(), info.args); 
    } 

    @Override 
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { 
    } 

    @Override 
    public void onPageSelected(int position) { 
     mActionBar.setSelectedNavigationItem(position); 
    } 

    @Override 
    public void onPageScrollStateChanged(int state) { 
    } 

    @Override 
    public void onTabSelected(Tab tab, FragmentTransaction ft) { 
     Object tag = tab.getTag(); 
     for (int i=0; i<mTabs.size(); i++) { 
      if (mTabs.get(i) == tag) { 
       mViewPager.setCurrentItem(i); 
      } 
     } 
    } 

    @Override 
    public void onTabUnselected(Tab tab, FragmentTransaction ft) { 
    } 

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

}

Answer 1

我們從FragmentActivity延長，當我們要使用Fragments在Android 3.0 <運行的設備。爲了在Android 2.3.3或類似軟件中使用Fragments，您需要FragmentActivity這是在Android support library。隨時隨地

private void LoadBundle() 
{ 
    Bundle b = getArguments(); 
     if (b != null) { 
     int value=b.getInt("yourkey") 
} 
} 

調用LoadBundle（）方法中加載傳遞到片段數據的片段 - ： 您也可以訪問以這種方式傳遞到片段中的包。

Answer 2

您可以從活動數據傳輸到分片這樣的：

FragmentA fragmentA = new FragmentA(); 
Bundle bundle = new Bundle(); 
bundle.putXXX("YourDataKey", YourDataValue); 
fragmentA.setArguments(bundle); 
getFragmentManager().beginTransaction().add(fragmentA); 

在我opion，爲什麼延伸FragmentActivity的原因是，它可以很容易地管理片段。使用Fragment的優點並不那麼簡單。請閱讀谷歌Android DOC： http://developer.android.com/guide/components/fragments.html