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Java 填充的RecyclerView为空_Java_Android_Xml - Fatal编程技术网

Java 填充的RecyclerView为空

Java 填充的RecyclerView为空,java,android,xml,Java,Android,Xml,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.I

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);
        }
    }
}
导入android.content.Context;
导入android.support.v7.widget.RecyclerView;
导入android.view.LayoutInflater;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.ImageView;
导入android.widget.TextView;
导入java.util.Collections;
导入java.util.List;
/**
*由anish于2014年12月29日创作。
*/
公共类MyAdapter扩展了RecyclerView.Adapter{
私人充气机;
List data=Collections.emptyList();
公共MyAdapter(上下文、列表数据)
{
充气器=从(上下文)开始充气;
这个。数据=数据;
}
@凌驾
公共MyViewHolder onCreateViewHolder(视图组父级,int-viewType){
视图=充气机。充气(R.layout.custom_行,父项,false);
MyViewHolder=新的MyViewHolder(视图);
报税表持有人;
}
@凌驾
公共无效onBindViewHolder(MyViewHolder,int位置){
信息当前=数据获取(位置);
holder.text.setText(当前名称);
}
@凌驾
public int getItemCount(){
返回data.size();
}
类MyViewHolder扩展了RecyclerView.ViewHolder{
文本查看文本;
公共MyViewHolder(查看项目视图){
超级(项目视图);
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);
    }
}
导入android.content.Context;
导入android.content.SharedReferences;
导入android.os.Bundle;
导入android.support.v4.app.Fragment;
导入android.support.v4.widget.DrawerLayout;
导入android.support.v7.app.ActionBarDrawerToggle;
导入android.support.v7.widget.LinearLayoutManager;
导入android.support.v7.widget.RecyclerView;
导入android.support.v7.widget.Toolbar;
导入android.view.LayoutInflater;
导入android.view.view;
导入android.view.ViewGroup;
导入java.util.ArrayList;
导入java.util.List;
/**
*一个简单的{@link Fragment}子类。
*/
公共类NavigationDrawerFragment扩展了片段{
私人回收站;
私有操作bardrawertoggle mDrawerToggle;
私人抽屉布局mDrawerLayout;
私有布尔mUserLearnedDrawer;
私有布尔值mFromSavedInstanceState;
公共静态最终字符串PREF_FILE_NAME=“testpref”;
公共静态最终字符串键\u USER\u LEARNED\u DRAWER=“USER\u LEARNED\u DRAWER”;
私有视图容器视图;
专用MyAdapter适配器;
公共导航抽屉碎片(){
//必需的空公共构造函数
}
@凌驾
创建时的公共void(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
mUserLearnedDrawer=Boolean.getBoolean(readFromPreferences(getActivity(),KEY\u USER\u LEARNED\u DRAWER,“false”);
如果(savedInstanceState!=null)mFromSavedInstanceState=true;
}
@凌驾
创建视图上的公共视图(布局、充气机、视图组容器、,
Bundle savedInstanceState){
视图布局=充气机。充气(R.layout.fragment\u navigation\u抽屉、容器,错误);
recyclerView=(recyclerView)layout.findViewById(R.id.drawer\u列表);
adapter=newmyadapter(getActivity(),getData());
recyclerView.setAdapter(适配器);
setLayoutManager(新的LinearLayoutManager(getActivity());
//为该碎片膨胀布局
返回布局;
}
公共静态列表getData()
{
列表数据=新的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={“微软”、“雅虎”、“谷歌”};

对于(int i=0;i您的模型中存在问题。您应该在模型类中使用getter和setter方法。以下代码可能会对您有所帮助

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中设置标题在我的例子中,我意识到适配器的
getItemCount()
方法从未被调用。在这种情况下,设置recyclerView的layoutmanager解决了我的问题

recyclerView.layoutManager = LinearLayoutManager(mainActivity)

在getItemCount()中添加一些日志。d做到了这一点,getCount()的值是3,正如预期的那样。BindViewHolder调用了三次?尝试运行hierarchyviewer?是的,它调用了三次。hierarchyviewer显示了什么?为什么这样做?添加getter和setter将如何改变问题?我这样做,但对我不起作用:/
recyclerView.layoutManager = LinearLayoutManager(mainActivity)