私はこのエラーを受け取っていますが、原因はわかりません...おそらく、アクティビティ自体ではなくフラグメントで初期化されているという事実と関係があります。編集:含まれているStatsAdapterコード
public class StatsFragment extends Fragment {
private RecyclerView mRecyclerView;
private LinearLayoutManager mLinearLayoutManager;
private RecyclerView.Adapter mAdapter;
private String[] myDataset = new String[]{"hello", "world", "yolo"};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_stats, parent, false);
mRecyclerView = (RecyclerView) v.findViewById(R.id.cardList);
mRecyclerView.setHasFixedSize(true);
mAdapter = new StatsAdapter(myDataset);
mRecyclerView.setAdapter(mAdapter);
mLinearLayoutManager = new LinearLayoutManager(getActivity());
mLinearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
return v;
}
}
public class StatsAdapter extends RecyclerView.Adapter<StatsAdapter.ViewHolder> {
private String[] mDataset;
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mTextView;
public ViewHolder(View v) {
super(v);
mTextView = (TextView) v.findViewById(R.id.title);
}
}
public StatsAdapter(String[] myDataset) {
mDataset = myDataset;
}
@Override
public StatsAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.fragment_stats, parent, false);
ViewHolder vh = new ViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.mTextView.setText(mDataset[position]);
}
@Override
public int getItemCount() {
return mDataset.length;
}
}
setLayoutManager
行をsetAdapter
の前に移動します
onCreate
にアダプターと「非表示」関連オブジェクトを作成します。次に、RecyclerView
にアダプターを使用します。
また、オブジェクトの使用とActivity
ライフサイクルに基づいてオブジェクトを明確な順序で開始することにより、コードをクリーンアップします。
public class StatsFragment extends Fragment {
private RecyclerView mRecyclerView;
private LinearLayoutManager mLinearLayoutManager;
private StatsAdapter mAdapter; // was RecyclerView.Adapter mAdapter;
private String[] myDataset = new String[]{"hello", "world", "yolo"};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 1.
mAdapter = new StatsAdapter(myDataset);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_stats, parent, false);
// 2.
mLinearLayoutManager = new LinearLayoutManager(getActivity());
mLinearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
// 3.
mRecyclerView = (RecyclerView) v.findViewById(R.id.cardList);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
mRecyclerView.setAdapter(mAdapter);
return v;
}
}
この問題を修正する1つの方法は、RecyclerViewに空のアダプターを接続することです
void initializeRecyclerView() {
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
recyclerView.setAdapter(new SampleAdapter(getCurrentActivity()));
recyclerView.setLayoutManager(new LinearLayoutManager(getCurrentActivity()));
recyclerView.setHasFixedSize(true);
}