Question

数据模型：

public class Information {

String title;}

适配器：

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.Collections;
import java.util.List;

/**
 * Created by anish on 29/12/14.
 */
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder>   {

    private LayoutInflater inflator;
    List<Information> data = Collections.emptyList();
    public MyAdapter(Context context, List<Information> data)
    {
        inflator = LayoutInflater.from(context);
        this.data=data;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflator.inflate(R.layout.custom_row, parent, false);
        MyViewHolder holder = new MyViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        Information current = data.get(position);
        holder.text.setText(current.title);
    }

    @Override
    public int getItemCount() {
        return data.size();
    }
    class MyViewHolder extends RecyclerView.ViewHolder{

        TextView text;

        public MyViewHolder(View itemView) {
            super(itemView);
            text = (TextView) itemView.findViewById(R.id.listText);
        }
    }
}

导航抽屉片段：

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;


/**
 * A simple {@link Fragment} subclass.
 */
public class NavigationDrawerFragment extends Fragment {

    private RecyclerView recyclerView;
    private ActionBarDrawerToggle mDrawerToggle;
    private DrawerLayout mDrawerLayout;
    private boolean mUserLearnedDrawer;
    private boolean mFromSavedInstanceState;
    public static final String PREF_FILE_NAME="testpref";
    public static final String KEY_USER_LEARNED_DRAWER="user_learned_drawer";
    private View containerView;
    private MyAdapter adapter;
    public NavigationDrawerFragment() {
        // Required empty public constructor
    }
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        mUserLearnedDrawer = Boolean.getBoolean(readFromPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,"false"));
        if(savedInstanceState!=null) mFromSavedInstanceState = true;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View layout = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
        recyclerView = (RecyclerView) layout.findViewById(R.id.drawer_list);
        adapter = new MyAdapter(getActivity(),getData());
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        // Inflate the layout for this fragment
        return layout;
    }

    public static List<Information> getData()
    {
        List<Information> data = new ArrayList<>();
        //int icons[]={R.drawable.abc_ic_ab_back_mtrl_am_alpha, R.drawable.abc_ab_share_pack_holo_dark, R.drawable.abc_btn_radio_to_on_mtrl_000};
        String[] title = {"Microsoft","Yahoo","Google"};
        for(int i=0; i<title.length; i++)
        {
            Information current = new Information();
            //current.iconId = icons[i];
            current.title = title[i];
            data.add(current);
        }
        return data;
    }
    public void setUp(int fragmentID, DrawerLayout drawerLayout, final Toolbar toolbar) {
        containerView = getActivity().findViewById(fragmentID);
        mDrawerLayout = drawerLayout;
        mDrawerToggle=new ActionBarDrawerToggle(getActivity(),drawerLayout,toolbar, R.string.drawer_open, R.string.drawer_close) {
            @Override
            public void onDrawerOpened(View drawerView) {
                if(!mUserLearnedDrawer)
                {
                    mUserLearnedDrawer=true;
                    saveToPreferences(getActivity(),KEY_USER_LEARNED_DRAWER,mUserLearnedDrawer+"");
                }
                getActivity().invalidateOptionsMenu();
                super.onDrawerOpened(drawerView);
            }

            @Override
            public void onDrawerClosed(View drawerView) {

                getActivity().invalidateOptionsMenu();
                super.onDrawerClosed(drawerView);
            }

            @Override
            public void onDrawerSlide(View drawerView, float slideOffset) {
                if(slideOffset<0.6)
                {
                    toolbar.setAlpha(1-slideOffset);

                }
            }
        };
        if(!mUserLearnedDrawer && !mFromSavedInstanceState)
        {
            mDrawerLayout.openDrawer(containerView);
        }
        mDrawerLayout.setDrawerListener(mDrawerToggle);
        mDrawerLayout.post(new Runnable() {
            @Override
            public void run() {
                mDrawerToggle.syncState();
            }
        });
    }
    public static void saveToPreferences(Context context, String preferenceName, String preferenceValue)
    {
        SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(preferenceName, preferenceValue);
        editor.apply();

    }
    public static String readFromPreferences(Context context, String preferenceName, String defaultValue)
    {
        SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
        return sharedPreferences.getString(preferenceName, defaultValue);
    }
}

我正在填充的单个行的XML：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/listText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Dummy Text"
        android:gravity="center"
        android:textColor="#0000"
        android:paddingTop="5dp"
        />
</LinearLayout>

当我运行应用程序时，NavigationDrawer为空白。我首先考虑使用ImageView，但出于调试目的，我想到只使用文本。我做了我所能做的一切。请帮忙。

Answer 1

模型类中存在问题。您应该在模型类中使用getter和setter方法。以下代码可以帮助您。

public class Information {
private String title;
public Model( String title) {
    super();
    this.title = title;
}
public String getTitle() {
    return title;
}
public void setTitle(String title) {
    this.title = title;
}
}

在MainActivity.java中，在MainActivity中设置标题

Answer 2

就我而言，我意识到永远不会调用适配器的 getItemCount() 方法。在这种情况下，设置 recyclerView 的 layoutmanager 解决了我的问题。

recyclerView.layoutManager = LinearLayoutManager(mainActivity)

填充的RecyclerView为空

2 个答案: