無法從活動調用片段方法

Question

我有活動，其中包含viewpager，每個選項卡上有一些片段。我想從片段調用一些方法。我正在使用：

android.support.v4.app.Fragment;

我的代碼： 主要活動：

public class ProfileActivity extends BaseTabsActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_profile); 
     initTabs(); 
     // call method here 
    } 
} 

    public class BaseTabsActivity extends BaseActivity { 

    protected void initTabs() { 
     ViewPager mViewPager = (ViewPager) findViewById(R.id.pager); 
     mViewPager.setOffscreenPageLimit(4); 
     mViewPager.setAdapter(new ProfileTabsAdapter(getSupportFragmentManager(), this)); 
    } 
} 

ProfileTabsAdapter：

public class ProfileTabsAdapter extends FragmentPagerAdapter { 

    public ProfileTabsAdapter(FragmentManager fm, Context context) { 
     super(fm); 
     this.context = context; 
    } 

    @Override 
    public Fragment getItem(int index) { 

     switch (index) { 
      case 0: 
       return new Fragment0(); 
      case 1: 
       return new Fragment1(); 
      case 2: 
       return new Fragment2(); 
      case 3: 
       return new Fragment3(); 
      case 4: 
       return new Fragment4(); 
     } 
     return null; 
    } 

    @Override 
    public int getCount() { 
     return 5; 
    } 

    @Override 
    public CharSequence getPageTitle(int index) { 
     switch (index) { 
      case 0: 
       return context.getResources().getString(R.string.string0); 
      case 1: 
       return context.getResources().getString(R.string.string1); 
      case 2: 
       return context.getResources().getString(R.string.string2); 
      case 3: 
       return context.getResources().getString(R.string.string3); 
      case 4: 
       return context.getResources().getString(R.string.string4); 
     } 
     return null; 
    } 

} 

片段：

public class Fragment0 extends Fragment { 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 

     View rootView = inflater.inflate(R.layout.fragment, container, false); 

     return rootView; 
    } 


    public String doSomething() { 
     return "hi"; 
    } 
} 

有什麼想法？

Answer 1

它的官方文檔中很好的描述：https://developer.android.com/training/basics/fragments/communicating.html

爲了您的舒適，這裏是代碼的相關部分：

ArticleFragment articleFrag = (ArticleFragment) 
     getSupportFragmentManager().findFragmentById(R.id.article_fragment); 

if (articleFrag != null) { 
    // If article frag is available, we're in two-pane layout... 

    // Call a method in the ArticleFragment to update its content 
    articleFrag.updateArticleView(position); 
} 

不過，請務必去閱讀我在開始時鏈接的文檔。