RecyclerView没有附加任何适配器

问题描述：

有一个活动的碎片容器，其中一个活动的开始添加了ViewPagerFragment。 MainFragment内部有一个RecyclerView（它是标签），显示但没有填充数据。试图改变宽度和高从0到Match_Parent和Fixed_Size。也改变ConstraintLayout到RelativeLayout.Using主题android:theme="@style/MyMaterialTheme" style.xmlRecyclerView没有附加任何适配器

<style name="MyMaterialTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar"> 
    <item name="windowNoTitle">true</item> 
    <item name="windowActionBar">false</item> 
    <item name="colorPrimary">@color/colorPrimary</item> 
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item> 
    <item name="colorAccent">@color/colorAccent</item> 
</style> 

<style name="MyMaterialTheme" parent="MyMaterialTheme.Base"> 
</style>

E/RecyclerView：无适配器连接;跳过

MainActivity.class 公共类MainActivity延伸AppCompatActivity {

private static final String TAG = "MainActivity"; 
private AdView mAdView; 
private FragmentTransaction mFragmentTransaction; 


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


    mAdView = (AdView) findViewById(R.id.adView); 

    AdRequest adRequest = new AdRequest.Builder() 
      .addTestDevice(AdRequest.DEVICE_ID_EMULATOR) 
      .build(); 
    mAdView.loadAd(adRequest); 

    mFragmentTransaction = getSupportFragmentManager() 
      .beginTransaction() 
      .add(R.id.container_frame, new ViewPagerFragment()); 
    mFragmentTransaction.commit(); 

} 

@Override 
protected void onResume() { 
    super.onResume(); 
    mAdView.resume(); 
} 

@Override 
protected void onPause() { 
    super.onPause(); 
    mAdView.pause(); 
} 

@Override 
protected void onDestroy() { 
    mAdView.destroy(); 
    super.onDestroy(); 
}

activity_main.xml中

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" 
             xmlns:tools="http://schemas.android.com/tools" 
             xmlns:ads="http://schemas.android.com/apk/res-auto" 
             xmlns:app="http://schemas.android.com/apk/res-auto" 
             android:layout_width="match_parent" 
             android:layout_height="match_parent" 
             android:background="@color/colorPrimaryDark" 
             tools:context="com.newakkoff.justad.Activities.MainActivity"> 

<RelativeLayout 
    ads:layout_constraintBottom_toTopOf="@+id/adView" 
    ads:layout_constraintTop_toTopOf="parent" 
    ads:layout_constraintLeft_toLeftOf="parent" 
    ads:layout_constraintRight_toRightOf="parent" 
    android:id="@+id/container_frame" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent"> 

</RelativeLayout> 

<com.google.android.gms.ads.AdView 
    android:id="@+id/adView" 
    android:layout_width="0dp" 
    ads:adSize="BANNER" 
    ads:adUnitId="@string/banner_ad_unit_id" 
    app:layout_constraintBottom_toBottomOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintLeft_toLeftOf="parent" 
    tools:layout_constraintRight_creator="1" 
    tools:layout_constraintLeft_creator="1" 
    android:layout_height="50dp"> 
</com.google.android.gms.ads.AdView> 
</android.support.constraint.ConstraintLayout>

ViewPagerFragment.class

public class ViewPagerFragment extends Fragment { 

private ViewPager mViewPager; 
private Toolbar mToolbar; 
private TabLayout mTableLayout; 
int i = 1; 



@Override 
public void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setHasOptionsMenu(true); 

} 

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

    return inflater.inflate(R.layout.fragment_view_pager, container, false) ; 
} 

@Override 
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
    super.onViewCreated(view, savedInstanceState); 
    mToolbar = (Toolbar) view.findViewById(R.id.toolbar); 
    ((AppCompatActivity) getActivity()).setSupportActionBar(mToolbar); 

    ((AppCompatActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false); 



    mViewPager = (ViewPager) view.findViewById(R.id.view_pager_main); 
    mViewPager.setAdapter(new CustomPagerAdapter(getActivity())); 
    mViewPager.setCurrentItem(1); 

    mTableLayout = (TabLayout) view.findViewById(R.id.tabs); 
    mTableLayout.setupWithViewPager(mViewPager); 
} 

@Override 
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 
    inflater.inflate(R.menu.menu_main, menu); 
    super.onCreateOptionsMenu(menu, inflater); 

} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
} 
}

fragment_view_pager.xm升

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.AppBarLayout 
    android:layout_width="0dp" 
    android:layout_height="wrap_content" 
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" 
    android:id="@+id/appBarLayout" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="parent"> 

    <android.support.v7.widget.Toolbar 
     android:id="@+id/toolbar" 
     android:layout_width="match_parent" 
     android:layout_height="?attr/actionBarSize" 
     android:background="?attr/colorPrimary" 

     /> 

    <android.support.design.widget.TabLayout 
     android:id="@+id/tabs" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     /> 

</android.support.design.widget.AppBarLayout> 

<android.support.v4.view.ViewPager 
android:id="@+id/view_pager_main" 
app:layout_constraintTop_toBottomOf="@+id/appBarLayout" 
app:layout_constraintRight_toRightOf="parent" 
app:layout_constraintLeft_toLeftOf="parent" 
app:layout_constraintBottom_toBottomOf="parent" 
android:layout_width="0dp" 
android:layout_height="0dp">

MainFragment.class

public class MainFragment extends Fragment { 


private RecyclerView mRecyclerView; 
private MyAdapter mAdapter; 
private LinearLayoutManager mLayoutManager; 

@Override 
public void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    mLayoutManager = new LinearLayoutManager(this.getActivity(),LinearLayoutManager.VERTICAL,false); 
    mAdapter = new MyAdapter(new String[]{"test one", "test two", "test three", "test four", "test five", "test six", "test seven"}); 
} 

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

    mRecyclerView = (RecyclerView) view.findViewById(R.id.rv_recycler_view); 
    mRecyclerView.setHasFixedSize(true); 
    mRecyclerView.setLayoutManager(mLayoutManager); 
    mRecyclerView.setAdapter(mAdapter); 

    return view; 
} 

@Override 
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
    super.onViewCreated(view, savedInstanceState); 

}

fragment_main.xml

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent"> 

<android.support.v7.widget.RecyclerView 
    android:id="@+id/rv_recycler_view" 
    android:layout_width="0dp" 
    android:layout_height="0dp" 
    android:layout_marginStart="8dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginLeft="8dp" 
    android:layout_marginEnd="8dp" 
    app:layout_constraintRight_toRightOf="parent" 
    android:layout_marginRight="8dp" 
    android:layout_marginTop="8dp" 
    app:layout_constraintTop_toTopOf="parent" 
    app:layout_constraintBottom_toBottomOf="parent" 
    android:layout_marginBottom="8dp" 
    tools:listitem="@layout/card_item" 
    android:background="@color/colorPrimary"/> 
</android.support.constraint.ConstraintLayout>

CustomPageAdapter.class

public class CustomPagerAdapter extends PagerAdapter { 

private Context mContext; 

public CustomPagerAdapter(Context context) { 
    mContext = context; 
} 

@Override 
public Object instantiateItem(ViewGroup container, int position) { 
    ModelPager modelsPager = ModelPager.values()[position]; 
    LayoutInflater inflater = LayoutInflater.from(mContext); 
    ViewGroup layout = (ViewGroup) inflater.inflate(modelsPager.getLayoutResId(), container, false); 
    container.addView(layout); 
    return layout; 
} 

@Override 
public void destroyItem(ViewGroup container, int position, Object object) { 
    container.removeView((View) object); 
} 

@Override 
public int getCount() { 
    return ModelPager.values().length; 
} 

@Override 
public boolean isViewFromObject(View view, Object object) { 
    return view == object; 
} 


@Override 
public CharSequence getPageTitle(int position) { 
    ModelPager customPagerEnum = ModelPager.values()[position]; 
    return mContext.getString(customPagerEnum.getTitleResId()); 
} 
}

ModelPager.class

public enum ModelPager { 
SEND_FRAGMENT(R.string.send_fragment_tab,R.layout.fragment_send), 
MAIN_FRAGMENT(R.string.main_fragment_tab, R.layout.fragment_main), 
ABOUT_FRAGMENT(R.string.about_fragment_tab, R.layout.fragment_about); 

private int mTitleResId; 
private int mLayoutResId; 

ModelPager(int titleResId, int layoutResId) { 
    mTitleResId = titleResId; 
    mLayoutResId = layoutResId; 
} 

public int getTitleResId() { 
    return mTitleResId; 
} 

public int getLayoutResId() { 
    return mLayoutResId; 
} 
}

MyAdapter.class

 public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> { 

    private String[] mDataset; 


    // Provide a reference to the views for each data item 
    // Complex data items may need more than one view per item, and 
    // you provide access to all the views for a data item in a view holder 
    static class MyViewHolder extends RecyclerView.ViewHolder { 
     private static final String TAG = "My Recycler Adapter"; 
     CardView mCardView; 
     TextView mTextView; 

     MyViewHolder(View v) { 
      super(v); 

      v.setOnClickListener(new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        Log.d(TAG, "Element " + getAdapterPosition() + " clicked."); 
       } 
      }); 
      mCardView = (CardView) v.findViewById(R.id.card_view); 
      mTextView = (TextView) v.findViewById(R.id.tv_text); 
     } 
    } 

    // Provide a suitable constructor (depends on the kind of dataset) 
    public MyAdapter(String[] myDataset) { 

     mDataset = myDataset; 
    } 

    // Create new views (invoked by the layout manager) 
    @Override 
    public MyAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, 
                int viewType) { 
     // create a new view 
     View v = LayoutInflater.from(parent.getContext()) 
       .inflate(R.layout.card_item, parent, false); 
     // set the view's size, margins, paddings and layout parameters 
     return new MyViewHolder(v); 
    } 

    @Override 
    public void onBindViewHolder(MyViewHolder holder, int position) { 
     holder.mTextView.setText(mDataset[position]); 
    } 

    @Override 
    public int getItemCount() { 
     return mDataset.length; 
    } 
}

card_item.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
      android:layout_width="match_parent" 
      android:layout_height="68dp" > 

<android.support.v7.widget.CardView 
    android:id="@+id/card_view" 
    xmlns:card_view="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_margin="10dp" 
    android:layout_height="62dp" 
    card_view:cardCornerRadius="4dp" 
    card_view:elevation="14dp"> 

     <TextView 
      android:id="@+id/tv_text" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:textColor="#000000" 
      android:gravity="center" > 
     </TextView> 


</android.support.v7.widget.CardView> 

</RelativeLayout>

你可以发布'CustomPAgerAdapter'的代码吗？ –

@VeneetReddy补充说，你可以检查吗？ – newakkoff

为什么要将'RecyclerView'的'layout_height'和'layout_width'设置为0dp？ –

答

唯一能合乎逻辑地处理该错误的地方是mRecyclerView.setAdapter(mAdapter);，因为它是唯一的RecyclerView。

查看文档mAdapter允许为null表示没有适配器。所以要么这个变量是null或者它没有正确实现RecyclerView.Adapter接口。

只是添加，也是当'setAdapter'调用延迟：http://stackoverflow.com/questions/29141729/recyclerview-no-adapter-attached-skipping-layout –

我的mAdapter不为空我检查 – newakkoff

RecyclerView没有附加任何适配器

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