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私は、Competitorオブジェクトのリストを持つrecyclerViewを持っています。 RecyclerViewを読み込むリストはグローバルシングルトンです。そのSingletonのコンストラクタで、私はJsonファイルを開き、その内容を解析してグローバルSingletonの競合者のリストを作成し、そのリストを使用してRecyclerViewのアダプタに渡します。各リスト項目にはImageButtonがあります。これが私が達成しようとしていることです。 ユーザーがImageButton（Delete Button）をクリックすると、AlertDialogがポップアップして、競合他社を削除してもよいかどうかを確認するメッセージが表示されます。私はこれまでにこの部分を持っています。しかし、私が次にする必要があることはわかりません。私はグローバルリストの情報を含むjsonファイルを更新することができますが、RecyclerViewから競合他社を削除してrecyclerviewを更新したいと考えています：外部AlertDialogからのアクティビティのリストにアクセスする方法
mCompetitorsList.remove（competitor）; notifyItemRemoved（位置）;
しかし、外部DialogクラスからmCompetitorsList変数への参照を取得できません。 notifiyItemRemoved（位置）を呼び出す場合も同じです
どうすればよいですか？以下は、私のDialogクラスのコードです。RecyclerViewとそのアダプターだけでなく、シングルトンの実装も含まれています。ここで
public class MasterCompetitorsListActivity extends AppCompatActivity implements SearchView.OnQueryTextListener {
private static final String DIALOG_DELETE_COMPETITOR = "DIALOG_DELETE_COMPETITOR";
private RecyclerView mRecyclerView;
private List<Competitor> mCompetitorsList;
private CompetitorListAdapter mAdapter;
private SearchView mSearchView;
private FloatingActionButton mAddCompetitorButton;
private Button mDeletCompetitor;
private TextView mCompetitorHidden;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_master_competitors_list);
mSearchView = (SearchView) findViewById(R.id.searchView);
mSearchView.setOnQueryTextListener(this);
/* initialize the Global Competitor's List for the recyclerview. Because this is a singleton
it should initialize the list for the entire app's runtime
*/
GlobalCompetitorsList.get();
mCompetitorsList = GlobalCompetitorsList.getCompetitors();
mRecyclerView = (RecyclerView) findViewById(R.id.master_competitors_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(layoutManager);
mAdapter = new CompetitorListAdapter(this, mCompetitorsList);
mRecyclerView.setAdapter(mAdapter);
// set a separator for the list items
DividerItemDecoration divider = new DividerItemDecoration(
mRecyclerView.getContext(),
layoutManager.getOrientation());
divider.setDrawable(ContextCompat.getDrawable(MasterCompetitorsListActivity.this, R.drawable.divider_dark));
mRecyclerView.addItemDecoration(divider);
mRecyclerView.setAdapter(mAdapter);
mAddCompetitorButton = (FloatingActionButton) findViewById(R.id.add_master_competitor_floating_button);
mAddCompetitorButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MasterCompetitorsListActivity.this, AddNewMasterCompetitorActivity.class);
startActivity(intent);
}
});
}
@Override
public boolean onQueryTextSubmit(String query) {
mCompetitorsList = new ArrayList<>();
mCompetitorsList = GlobalCompetitorsList.getCompetitors();
mAdapter.notifyDataSetChanged();
return false;
}
@Override
public boolean onQueryTextChange(String query) {
mCompetitorsList = GlobalCompetitorsList.getCompetitors();
query = query.toLowerCase();
final List<Competitor> filteredList = new ArrayList<>();
for (int i = 0; i < mCompetitorsList.size(); i++) {
final String lastName = mCompetitorsList.get(i).getLastName().toLowerCase();
final String firstName = mCompetitorsList.get(i).getFirstName().toLowerCase();
if (lastName.contains(query) || firstName.contains(query)) {
filteredList.add(mCompetitorsList.get(i));
}
}
mAdapter.setFilter(filteredList);
return true;
}
// ********* RecyclerView Adapter class *************************************************************************
public class CompetitorListAdapter extends RecyclerView.Adapter<CompetitorListAdapter.CompetitorViewHolder> {
List<Competitor> mCompetitors;
Context mContext;
public CompetitorListAdapter(Context context, List<Competitor> competitors) {
mContext = context;
mCompetitors = competitors;
}
@Override
public CompetitorListAdapter.CompetitorViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(MasterCompetitorsListActivity.this);
View itemView = inflater.inflate(R.layout.list_item_master_competitor, parent, false);
CompetitorViewHolder viewHolder = new CompetitorViewHolder(itemView);
return viewHolder;
}
@Override
public void onBindViewHolder(CompetitorListAdapter.CompetitorViewHolder holder, final int position) {
final Competitor competitor = mCompetitorsList.get(position);
try {
holder.firstName.setText(competitor.getFirstName());
holder.lastName.setText(competitor.getLastName());
holder.memberNum.setText(competitor.getMemberNum());
holder.deleteCompetitor.setImageResource(R.drawable.ic_delete_forever_white_24dp);
holder.container.findViewById(R.id.main_container);
holder.hiddenCompetitorId.setText(competitor.getCompetitorId().toString());
} catch (Exception e) {
e.printStackTrace();
}
holder.deleteCompetitor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
FragmentManager fragmentManager = getSupportFragmentManager();
DeleteCompetitorDialogFragment dialog = new DeleteCompetitorDialogFragment();
dialog.show(fragmentManager, DIALOG_DELETE_COMPETITOR);
// mCompetitorsList.remove(competitor); // remove from the global singleton list
// notifyItemRemoved(position);
}
});
}
@Override
public int getItemCount() {
return mCompetitorsList.size();
}
// ************* View Holder Class **************************************************************************
public class CompetitorViewHolder extends RecyclerView.ViewHolder {
public TextView firstName;
public TextView lastName;
public TextView memberNum;
public ImageButton deleteCompetitor;
public ConstraintLayout container;
public TextView hiddenCompetitorId;
boolean comptitorIsActive = false;
public CompetitorViewHolder(final View itemView) {
super(itemView);
firstName = (TextView) itemView.findViewById(R.id.first_name);
lastName = (TextView) itemView.findViewById(R.id.last_name);
deleteCompetitor = (ImageButton) itemView.findViewById(R.id.delete_competitor_button);
hiddenCompetitorId = (TextView) itemView.findViewById(R.id.competitor_id_hidden);
container = (ConstraintLayout) itemView.findViewById(R.id.main_container);
memberNum = (TextView) itemView.findViewById(R.id.member_num);
}
}
// ************ End of View Holder Class ********************************************************************
public void setFilter(List<Competitor> newList) {
mCompetitorsList = new ArrayList<>();
mCompetitorsList.addAll(newList);
notifyDataSetChanged();
}
}
// ************* End of RecyclerView Adapter class **********************************************************
}
ダイアログクラスです：
public class DeleteCompetitorDialogFragment extends DialogFragment {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState){
final GlobalCompetitorsList mCompetitorsList = GlobalCompetitorsList.get();
return new AlertDialog.Builder(getActivity())
.setTitle("Delete this Competitor?")
.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
}
})
.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
// remove from the master_competitors.json file by overwriting the original file with the new
// global list
File file = new File("data/data/com.checkinsystems.ez_score/files/master_competitors.json");
if (file.exists()) {
FileOutputStream fos = null;
try {
String jsonString = new Gson().toJson(mCompetitorsList);
fos = getActivity().openFileOutput("master_competitors.json", getActivity().MODE_PRIVATE);
fos.write(jsonString.getBytes());
// somehow access the list from the calling activity to remove the item
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
assert fos != null;
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
})
.create();
}
}
そしてそれはここで、私のコードを理解するのに役立ちます場合はシングルトンクラス
public class GlobalCompetitorsList {
public static GlobalCompetitorsList sGlobalCompetitorsList;
public static List<Competitor> sCompetitors;
public static GlobalCompetitorsList get() {
if(sGlobalCompetitorsList == null){
return new GlobalCompetitorsList();
} else {
return sGlobalCompetitorsList;
}
}
private GlobalCompetitorsList() {
File file = new File("data/data/com.checkinsystems.ez_score/files/master_competitors.json");
String jsonString;
if(file.exists()){
BufferedReader reader = null;
List<Competitor> list;
sCompetitors = new ArrayList<>();
try {
reader = new BufferedReader(new FileReader(file));
jsonString = reader.readLine();
Type compType = new TypeToken<List<Competitor>>(){}.getType();
list = new Gson().fromJson(jsonString, compType);
addCompetitors(list);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
assert reader != null;
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} else {
sCompetitors = new ArrayList<>();
}
}
public void addCompetitor(Competitor c){
sCompetitors.add(c);
}
public static void addCompetitors(List<Competitor> c){
sCompetitors.addAll(c);
}
public static List<Competitor> getCompetitors(){
return sCompetitors;
}
}