notifyDataSetChanged（）不适用于SearchView

Question

我试图在ActionBar中实现SearchView。我在适配器中使用notifyDataSetChanged()，但Fragment未更新。我正在使用调试器，似乎流程正常，但只有Fragment不再运行。这里是我的代码：

这是我的适配器类：

public class DessertAdapter extends RecyclerView.Adapter<DessertAdapter.DessertVh> { 


private List<Dessert> desserts = new ArrayList<>(); 
OnItemClickListener clickListener; 
private Context context; 

public DessertAdapter(Context context) { 
    this.context = context; 

    desserts = Dessert.prepareDesserts(
      context.getResources().getStringArray(R.array.dessert_names), 
      context.getResources().getStringArray(R.array.dessert_descriptions)); 
} 

public void setFilter(ArrayList<Dessert> newList){ 
    desserts = new ArrayList<>(); 
    desserts.addAll(newList); 
    notifyDataSetChanged(); 
} 

@Override 
public DessertVh onCreateViewHolder(ViewGroup parent, int viewType) { 
    LayoutInflater inflater = LayoutInflater.from(parent.getContext()); 
    View view = inflater.inflate(R.layout.item_dessert, parent, false); 
    return new DessertAdapter.DessertVh(view); 
} 

@Override 
public void onBindViewHolder(DessertVh holder, int position) { 
    Dessert dessert = desserts.get(position); 

    holder.mName.setText(dessert.getName()); 
    holder.mDescription.setText(dessert.getDescription()); 
    holder.mFirstLetter.setText(String.valueOf(dessert.getFirstLetter())); 

} 

@Override 
public int getItemCount() { 
    return desserts == null ? 0 : desserts.size(); 
} 

public class DessertVh extends RecyclerView.ViewHolder implements View.OnClickListener{ 

    private TextView mName; 
    private TextView mDescription; 
    private TextView mFirstLetter; 

    public DessertVh(View itemView) { 
     super(itemView); 

     mName = (TextView) itemView.findViewById(R.id.txt_name); 
     mDescription = (TextView) itemView.findViewById(R.id.txt_desc); 
     mFirstLetter = (TextView) itemView.findViewById(R.id.txt_firstletter); 

     itemView.setOnClickListener(this); 
    } 

    @Override 
    public void onClick(View v) { 
     clickListener.onItemClick(v, getPosition()); 
    } 
} 

public interface OnItemClickListener { 
    public void onItemClick(View view, int position); 
} 

public void SetOnItemClickListener(final OnItemClickListener itemClickListener) { 
    this.clickListener = itemClickListener; 
} 
} 

这是我的Activity类，即由片段和FragmentPagerAdapter的还有：

public class TabsHeaderActivity extends AppCompatActivity implements SearchView.OnQueryTextListener{ 
private static final String TAG = TabsHeaderActivity.class.getSimpleName(); 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_tabs_header); 

    final Toolbar toolbar = (Toolbar) findViewById(R.id.htab_toolbar); 
    setSupportActionBar(toolbar); 
    if (getSupportActionBar() != null) getSupportActionBar().setTitle("TECHNOLOGY"); 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 

    final ViewPager viewPager = (ViewPager) findViewById(R.id.htab_viewpager); 
    setupViewPager(viewPager); 


    TabLayout tabLayout = (TabLayout) findViewById(R.id.htab_tabs); 
    tabLayout.setupWithViewPager(viewPager); 

    final CollapsingToolbarLayout collapsingToolbarLayout = (CollapsingToolbarLayout) findViewById(R.id.htab_collapse_toolbar); 

    try { 
     Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.edtech); 
     Palette.from(bitmap).generate(new Palette.PaletteAsyncListener() { 
      @SuppressWarnings("ResourceType") 
      @Override 
      public void onGenerated(Palette palette) { 

       int vibrantColor = palette.getVibrantColor(R.color.primary_500); 
       int vibrantDarkColor = palette.getDarkVibrantColor(R.color.primary_700); 
       collapsingToolbarLayout.setContentScrimColor(vibrantColor); 
       collapsingToolbarLayout.setStatusBarScrimColor(vibrantDarkColor); 
      } 
     }); 

    } catch (Exception e) { 
     // if Bitmap fetch fails, fallback to primary colors 
     Log.e(TAG, "onCreate: failed to create bitmap from background", e.fillInStackTrace()); 
     collapsingToolbarLayout.setContentScrimColor(
       ContextCompat.getColor(this, R.color.primary_500) 
     ); 
     collapsingToolbarLayout.setStatusBarScrimColor(
       ContextCompat.getColor(this, R.color.primary_700) 
     ); 
    } 

    tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() { 
     @Override 
     public void onTabSelected(TabLayout.Tab tab) { 

      viewPager.setCurrentItem(tab.getPosition()); 
      Log.d(TAG, "onTabSelected: pos: " + tab.getPosition()); 

      switch (tab.getPosition()) { 
       case 0: 
        // TODO: 31/03/17 
        break; 
      } 
     } 

     @Override 
     public void onTabUnselected(TabLayout.Tab tab) { 

     } 

     @Override 
     public void onTabReselected(TabLayout.Tab tab) { 

     } 
    }); 
} 

private void setupViewPager(ViewPager viewPager) { 
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager()); 
    adapter.addFrag(new DummyFragment(
      ContextCompat.getColor(this, R.color.cyan_50)), "Cyan"); 
    adapter.addFrag(new DummyFragment(
      ContextCompat.getColor(this, R.color.amber_50)), "Amber"); 
    adapter.addFrag(new DummyFragment(
      ContextCompat.getColor(this, R.color.purple_50)), "Purple"); 
    adapter.addFrag(new DummyFragment(
      ContextCompat.getColor(this, R.color.grey)), "Grey"); 
    viewPager.setAdapter(adapter); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.menu_main, menu); 

    MenuItem menuItem = menu.findItem(R.id.menuSearch); 
    SearchView searchView = (SearchView) MenuItemCompat.getActionView(menuItem); 
    searchView.setOnQueryTextListener(this); 
    return true; 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    switch (item.getItemId()) { 
     case android.R.id.home: 
      finish(); 
      return true; 
     case R.id.menuSearch: 
      return true; 
    } 
    return super.onOptionsItemSelected(item); 
} 

@Override 
public boolean onQueryTextSubmit(String query) { 
    return false; 
} 

@Override 
public boolean onQueryTextChange(String newText) { 

    newText = newText.toLowerCase(); 
    ArrayList<Dessert> newList = new ArrayList<>(); 

    for(Dessert dessert : Dessert.desserts){ 
     String name = dessert.getName().toLowerCase(); 
     if(name.contains(newText)){ 
      newList.add(dessert); 
     } 
    } 

    new DessertAdapter(getBaseContext()).setFilter(newList); 
    return true; 
} 

private static class ViewPagerAdapter extends FragmentPagerAdapter{ 
    private final List<Fragment> mFragmentList = new ArrayList<>(); 
    private final List<String> mFragmentTitleList = new ArrayList<>(); 

    public ViewPagerAdapter(FragmentManager manager) { 
     super(manager); 
    } 

    @Override 
    public Fragment getItem(int position) { 
     return mFragmentList.get(position); 
    } 

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

    public void addFrag(Fragment fragment, String title) { 
     mFragmentList.add(fragment); 
     mFragmentTitleList.add(title); 
    } 

    @Override 
    public CharSequence getPageTitle(int position) { 
     return mFragmentTitleList.get(position); 
    } 

    @Override 
    public int getItemPosition(Object object) { 
     return POSITION_NONE; 
    } 
} 

public static class DummyFragment extends Fragment{ 
    int color; 
    Intent intent; 
    DessertAdapter adapter; 

    public DummyFragment() { 
    } 

    @SuppressLint("ValidFragment") 
    public DummyFragment(int color) { 
     this.color = color; 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     View view = inflater.inflate(R.layout.dummy_fragment, container, false); 

     final FrameLayout frameLayout = (FrameLayout) view.findViewById(R.id.dummyfrag_bg); 
     frameLayout.setBackgroundColor(color); 

     RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.dummyfrag_scrollableview); 

     LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity().getBaseContext()); 
     recyclerView.setLayoutManager(linearLayoutManager); 
     recyclerView.setHasFixedSize(true); 

     adapter = new DessertAdapter(getContext()); 
     recyclerView.setAdapter(adapter); 
return view; 
    } 

} 
} 

Answer 1

您在调用设置的过滤一个DessertAdapter的新实例，而不是您设置为回收站视图的适配器实例。

您应该在DummyFragment中定义一个接口，允许活动向其传递搜索视图查询。

然后在已经在片段中实例化的DessertAdapter实例上调用setFilter。