Java 更新recyclerview数据
几天后,我尝试在viewpager2的recyclerview中处理数据。viewpager有一个适配器,用于管理recyclerview中的数据。但我尝试做的一切似乎都不起作用。也许我误解了目的或是别的什么。我希望你能帮助我 此活动管理viewpager及其适配器。它将数据发送到内部recyclerview:Java 更新recyclerview数据,java,android,android-recyclerview,android-viewpager2,Java,Android,Android Recyclerview,Android Viewpager2,几天后,我尝试在viewpager2的recyclerview中处理数据。viewpager有一个适配器,用于管理recyclerview中的数据。但我尝试做的一切似乎都不起作用。也许我误解了目的或是别的什么。我希望你能帮助我 此活动管理viewpager及其适配器。它将数据发送到内部recyclerview: public class AudioFilePanel extends AppCompatActivity { private String currentTab; pr
public class AudioFilePanel extends AppCompatActivity
{
private String currentTab;
private ViewPagerAdapter adapter;
private ViewPager2 viewPager;
private TabLayout tabLayout;
private Map<String, List<String>> content;
private String path;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_audio_file_panel);
viewPager = findViewById(R.id.view_pager2);
tabLayout = findViewById(R.id.tabs);
Button addFilesByTag = findViewById(R.id.add_files_with_tag);
if (null == currentTab)
{
currentTab = "music";
}
content = listByTag();
adapter = new ViewPagerAdapter(getApplicationContext(), new ArrayList<>(content.values()));
viewPager.setAdapter(adapter);
new TabLayoutMediator(tabLayout, viewPager,
(tab, position) -> tab.setText(content.keySet().toArray()[position].toString())).attach();
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener()
{
@Override
public void onTabSelected(TabLayout.Tab tab)
{
currentTab = tab.getText().toString();
}
@Override
public void onTabUnselected(TabLayout.Tab tab)
{
}
@Override
public void onTabReselected(TabLayout.Tab tab)
{
}
});
addFilesByTag.setOnClickListener(l ->
{
Intent fileBrowser = new Intent(AudioFilePanel.this, FileBrowser.class);
startActivityForResult(fileBrowser, 1);
});
}
private void updateViweData()
{
content = listByTag();
adapter = new ViewPagerAdapter(getApplicationContext(), new ArrayList<>(content.values()));
viewPager.setAdapter(adapter);
}
private Map<String, List<String>> listByTag()
{
Map<String, List<String>> result = new HashMap<>();
DirectoryDao dao = new DirectoryDao(getApplicationContext());
String[] categories = {"music", "ambience", "effect"};
for (String category : categories)
{
List<String> directories =
dao.getDirectoriesForCategory(category).stream().map(Directory::getPath).collect(Collectors.toList());
result.put(category, directories);
}
return result;
}
公共类AudioFilePanel扩展AppCompative活动
{
私有字符串当前选项卡;
专用ViewPagerAdapter适配器;
私有ViewPager2 viewPager;
私人摊位摊位;
私有地图内容;
私有字符串路径;
@凌驾
创建时受保护的void(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u audio\u file\u面板);
viewPager=findViewById(R.id.view\u pager2);
tabLayout=findviewbyd(R.id.tabs);
按钮addFilesByTag=findViewById(R.id.add_files_with_tag);
如果(null==currentTab)
{
currentTab=“音乐”;
}
content=listByTag();
adapter=newviewPageRadapter(getApplicationContext(),newArrayList(content.values());
viewPager.setAdapter(适配器);
新的TabLayoutMediator(tabLayout、viewPager、,
(选项卡,位置)->tab.setText(content.keySet().toArray()[position].toString()).attach();
tabLayout.addOnTabSelectedListener(新的tabLayout.OnTabSelectedListener()
{
@凌驾
已选择的公共选项卡(TabLayout.Tab)
{
currentTab=tab.getText().toString();
}
@凌驾
已选择的公共选项卡(TabLayout.Tab)
{
}
@凌驾
已重新选择公共选项卡(TabLayout.Tab)
{
}
});
addFilesByTag.setOnClickListener(l->
{
Intent fileBrowser=新Intent(AudioFilePanel.this,fileBrowser.class);
startActivityForResult(文件浏览器,1);
});
}
私有void updateViweData()
{
content=listByTag();
adapter=newviewPageRadapter(getApplicationContext(),newArrayList(content.values());
viewPager.setAdapter(适配器);
}
私有映射listByTag()
{
映射结果=新的HashMap();
DirectoryDao=newdirectorydao(getApplicationContext());
字符串[]类别={“音乐”、“氛围”、“效果”};
用于(字符串类别:类别)
{
列出目录=
getDirectoriesForCategory(category).stream().map(Directory::getPath).collect(Collectors.toList());
结果。放置(类别、目录);
}
返回结果;
}
这是视图寻呼机适配器。它直接从活动中获取数据,每次单击某个项目时,都应触发内部回收视图中的数据更新。请参见第118-128行:
public class ViewPagerAdapter extends RecyclerView.Adapter<ViewPagerAdapter.ViewHolder>
{
private List<List<String>> filesListsByCategory;
private LayoutInflater mInflater;
private Context ctx;
private ItemListAdapter adapter;
private List<String> categoryFiles;
public ViewPagerAdapter(Context context, List<List<String>> data)
{
this.mInflater = LayoutInflater.from(context);
this.filesListsByCategory = data;
this.ctx = context;
}
@NotNull
@Override
public ViewHolder onCreateViewHolder(@NotNull ViewGroup parent, int viewType)
{
return new ViewHolder(mInflater.inflate(R.layout.item_viewpager, parent, false));
}
@Override
public void onBindViewHolder(ViewHolder holder, int position)
{
FileBrowserService fbs = new FileBrowserService();
categoryFiles = filesListsByCategory.get(position);
adapter = new ItemListAdapter(categoryFiles, new ItemList.OnListFragmentInteractionListener()
{
@Override
public void onListFragmentInteraction(String item)
{
categoryFiles = fbs.getFiles(categoryFiles.get(position));
categoryFiles.add(0, "previous directory");
updateUi(adapter, holder);
}
});
holder.myView.setAdapter(adapter);
}
private void updateUi(ItemListAdapter adapter, ViewHolder holder)
{
adapter.notifyDataSetChanged();
holder.myView.setAdapter(adapter);
}
@Override
public int getItemCount()
{
return filesListsByCategory.size();
}
class ViewHolder extends RecyclerView.ViewHolder
{
RecyclerView myView;
RelativeLayout relativeLayout;
ViewHolder(View itemView)
{
super(itemView);
myView = itemView.findViewById(R.id.my_list);
myView.setLayoutManager(new LinearLayoutManager(ctx));
relativeLayout = itemView.findViewById(R.id.container);
}
}
}
公共类ViewPagerAdapter扩展了RecyclerView.Adapter
{
私有列表文件ListsByCategory;
私人停车场;
私有上下文ctx;
私有项列表适配器;
私有列表类别文件;
public ViewPagerAdapter(上下文、列表数据)
{
this.mInflater=LayoutInflater.from(上下文);
this.filesListsByCategory=数据;
this.ctx=上下文;
}
@NotNull
@凌驾
public ViewHolder onCreateViewHolder(@NotNull ViewGroup父级,int viewType)
{
返回新的ViewHolder(mInflater.flate(R.layout.item_viewpager,parent,false));
}
@凌驾
公共无效onBindViewHolder(ViewHolder,int位置)
{
FileBrowserService fbs=新的FileBrowserService();
categoryFiles=filesListsByCategory.get(位置);
adapter=new ItemListAdapter(categoryFiles,new ItemList.OnListFragmentInteractionListener()
{
@凌驾
public void onListFragmentInteraction(字符串项)
{
categoryFiles=fbs.getFiles(categoryFiles.get(position));
添加(0,“以前的目录”);
更新(适配器、支架);
}
});
holder.myView.setAdapter(适配器);
}
私有void updateUi(ItemListAdapter适配器、ViewHolder)
{
adapter.notifyDataSetChanged();
holder.myView.setAdapter(适配器);
}
@凌驾
public int getItemCount()
{
返回filelistsbycategory.size();
}
类ViewHolder扩展了RecyclerView.ViewHolder
{
回收视图myView;
相对的相对的;
ViewHolder(视图项视图)
{
超级(项目视图);
myView=itemView.findviewbyd(R.id.my_列表);
设置布局管理器(新的LinearLayoutManager(ctx));
relativeLayout=itemView.findViewById(R.id.container);
}
}
}
它是内部recyclerview的适配器。它仅表示元素列表:
public class ItemListAdapter extends RecyclerView.Adapter<ItemListAdapter.ViewHolder>
{
private List<String> files;
private final OnListFragmentInteractionListener mListener;
public ItemListAdapter(List<String> items, OnListFragmentInteractionListener listener)
{
files = items;
mListener = listener;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.fragment_item, parent, false));
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position)
{
holder.file = files.get(position);
holder.mContentView.setText(files.get(position));
holder.mView.setOnClickListener(v ->
{
if (null != mListener)
{
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mListener.onListFragmentInteraction(holder.file);
}
});
}
@Override
public int getItemCount()
{
return files.size();
}
class ViewHolder extends RecyclerView.ViewHolder
{
private final View mView;
private final TextView mContentView;
private String file;
private ViewHolder(View view)
{
super(view);
mView = view;
mContentView = view.findViewById(R.id.content);
}
}
}
公共类ItemListAdapter扩展了RecyclerView.Adapter
{
私人清单文件;
私有final OnListFragmentInteractionListener MLListener;
public ItemListAdapter(列表项,OnListFragmentInteractionListener侦听器)
{
文件=项目;
mListener=监听器;
}
@凌驾
public ViewHolder onCreateViewHolder(视图组父级,int-viewType)
{
返回新的ViewHolder(LayoutInflater.from(parent.getContext()).flate(R.layout.fragment_item,parent,false));
}
@凌驾
公共无效onBindViewHolder(最终ViewHolder,内部位置)
{
holder.file=files.get(位置);
holder.mContentView.setText(files.get(position));
holder.mView.setOnClickListener(v->
{
if(null!=mListener)
{
//通知活动回调接口(活动,如果
//
public class ItemList extends Fragment
{
// TODO: Customize parameter argument names
private static final String ARG_COLUMN_COUNT = "column-count";
// TODO: Customize parameters
private int mColumnCount = 1;
private OnListFragmentInteractionListener mListener;
/**
* Mandatory empty constructor for the fragment manager to instantiate the fragment (e.g. upon screen orientation
* changes).
*/
public ItemList()
{
}
// TODO: Customize parameter initialization
@SuppressWarnings("unused")
public static ItemList newInstance(int columnCount)
{
ItemList fragment = new ItemList();
Bundle args = new Bundle();
args.putInt(ARG_COLUMN_COUNT, columnCount);
fragment.setArguments(args);
return fragment;
}
@Override
public void onAttach(Context context)
{
super.onAttach(context);
if (context instanceof OnListFragmentInteractionListener)
{
mListener = (OnListFragmentInteractionListener) context;
} else
{
throw new RuntimeException(context.toString() + " must implement OnListFragmentInteractionListener");
}
}
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
if (getArguments() != null)
{
mColumnCount = getArguments().getInt(ARG_COLUMN_COUNT);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.fragment_item_list, container, false);
if (view instanceof RecyclerView)
{
Context context = view.getContext();
RecyclerView recyclerView = (RecyclerView) view;
if (mColumnCount <= 1)
{
recyclerView.setLayoutManager(new LinearLayoutManager(context));
} else
{
recyclerView.setLayoutManager(new GridLayoutManager(context, mColumnCount));
}
recyclerView.setAdapter(new ItemListAdapter(getArguments().getStringArrayList("list"), mListener));
}
return view;
}
@Override
public void onDetach()
{
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this fragment to allow an interaction in this
* fragment to be communicated to the activity and potentially other fragments contained in that activity.
* <p/>
* See the Android Training lesson
* <a href= "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnListFragmentInteractionListener
{
// TODO: Update argument type and name
void onListFragmentInteraction(String item);
}
}
public void updateData(List<String> filesList, int flag) {
if (flag == 0) { //append
for (int i = 0; i < filesList.size(); i++) {
files.add(messageList.get(i));
notifyItemInserted(getItemCount());
}
} else { //clear all
files.clear();
notifyDataSetChanged();
}
}
mItemListAdapter.updateData(yourNewListOfItems, 0);
mItemListAdapter.updateData(null, 1);