我有一个EditText，可以将项目添加到此RecyclerView和Realm数据库。这很好。问题是我不知道如何从RecyclerView和Realm数据库中删除这些项目。这应该在片段还是适配器上完成？如何？谢谢！
顶部有一个图片，显示该应用的屏幕截图。
以下是Fragment所在的RecyclerView：
public class FragmentMyList extends Fragment{
private RecyclerView recyclerView;
private EditText editTxt;
private FloatingActionButton btn;
private Item item;
private ArrayList<Item> itemList;
private AdapterItemsRecycler adapterItemsRecycler;
private Realm realm;
RealmResults<Item> results;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View vistaADevolver = inflater.inflate(R.layout.fragment_my_list, container, false);
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
Realm.init(getContext());
realm = Realm.getDefaultInstance();
editTxt = (EditText)vistaADevolver.findViewById(R.id.editText);
btn = (FloatingActionButton) vistaADevolver.findViewById(R.id.button);
recyclerView = (RecyclerView) vistaADevolver.findViewById(R.id.recyclerViewToDo);
itemList = new ArrayList<>();
results = realm.where(Item.class).equalTo("id", 1).findAll();
final InputMethodManager inputManager = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
adapterItemsRecycler = new AdapterItemsRecycler(results, getActivity(), new ItemsListener());
recyclerView.setHasFixedSize(true);
recyclerView.addItemDecoration(new SimpleItemDivider(getActivity()));
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity(),LinearLayoutManager.VERTICAL, false));
recyclerView.setAdapter(adapterItemsRecycler);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String itemName = editTxt.getText().toString();
saveIntoDatabase(itemName);
inputManager.hideSoftInputFromWindow(getView().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
editTxt.getText().clear();
adapterItemsRecycler.notifyDataSetChanged();
}
});
return vistaADevolver;
}
@Override
public void onDestroy() {
super.onDestroy();
realm.close();
}
private void saveIntoDatabase(final String itemName) {
realm.executeTransactionAsync(new Realm.Transaction() {
@Override
public void execute(Realm bgRealm) {
item = bgRealm.createObject(Item.class);
item.setName(itemName);
item.setPoint(itemName);
item.setId(1);
Fragment fragment = new Fragment();
Bundle bundle = new Bundle();
bundle.putString("POINT", item.getPoint());
fragment.setArguments(bundle);
itemList.add(item);
}
}, new Realm.Transaction.OnSuccess() {
@Override
public void onSuccess() {
// Transaction was a success.
Log.v("database", "Stored ok");
}
}, new Realm.Transaction.OnError() {
@Override
public void onError(Throwable error) {
// Transaction failed and was automatically canceled.
Log.e("database", error.getMessage());
}
});
}
class ItemsListener implements AdapterView.OnClickListener{
@Override
public void onClick(View view) {
Item itemTouched = results.get(recyclerView.getChildAdapterPosition(view));
EscuchadorInterface unEscuchador = (EscuchadorInterface)getActivity();
unEscuchador.itemSelected(itemTouched);
}
}
public interface EscuchadorInterface{
public void itemSelected(Item anItem);
}
}
我的RecyclerView适配器：
public class AdapterItemsRecycler extends RecyclerView.Adapter {
private RealmResults<Item> itemList;
private Context context;
private View.OnClickListener listener;
private Realm realm;
public AdapterItemsRecycler(RealmResults<Item> itemList, Context context, View.OnClickListener listener) {
this.itemList = itemList;
this.context = context;
this.listener = listener;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, final int viewType) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.my_list_detail, parent, false);
view.setOnClickListener(listener);
ItemViewHolder itemViewHolder = new ItemViewHolder(view);
return itemViewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
Item item = itemList.get(position);
ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
itemViewHolder.loadItem(item);
}
@Override
public int getItemCount() {
return itemList.size();
}
private class ItemViewHolder extends RecyclerView.ViewHolder{
private TextView itemText;
private ImageButton imageButton;
public ItemViewHolder(View view) {
super(view);
itemText = (TextView) view.findViewById(R.id.textViewItemNameTD);
imageButton = (ImageButton) view.findViewById(R.id.delete);
}
public void loadItem(Item item) {
itemText.setText(item.getName());
imageButton.setImageResource(R.drawable.trash);
}
public ImageButton getImageButton() {
return imageButton;
}
}
}
RecyclerView的详细信息：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:design="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
tools:context="com.segunfamisa.sample.bottomnav.MainActivity">
<ImageButton
android:id="@+id/delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:tint="#03A9F4"
android:scaleType="centerInside"
android:background="#ffffff"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:onClick="deleteItem"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textViewItemNameTD"
android:textSize="14dp"
android:textColor="#212121"
android:background="#ffffff"
android:padding="10dp"
android:layout_toRightOf="@+id/delete"/>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/arrow"
android:scaleType="centerInside"
android:background="#ffffff"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"/>
</RelativeLayout>
答案 0 :(得分：2)
直接使用RealmRecyclerViewAdapter直接使用RealmResults，自动处理数据库与列表和适配器之间的同步。
public class FragmentMyList
extends Fragment {
private RecyclerView recyclerView;
private EditText editTxt;
private FloatingActionButton btn;
private AdapterItemsRecycler adapterItemsRecycler;
private Realm realm;
RealmResults<Item> results;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View vistaADevolver = inflater.inflate(R.layout.fragment_my_list, container, false);
getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
Realm.init(getContext());
realm = Realm.getDefaultInstance();
editTxt = (EditText) vistaADevolver.findViewById(R.id.editText);
btn = (FloatingActionButton) vistaADevolver.findViewById(R.id.button);
recyclerView = (RecyclerView) vistaADevolver.findViewById(R.id.recyclerViewToDo);
results = realm.where(Item.class).equalTo("id", 1).findAll();
final InputMethodManager inputManager = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
adapterItemsRecycler = new AdapterItemsRecycler(results, new ItemsListener());
recyclerView.setHasFixedSize(true);
recyclerView.addItemDecoration(new SimpleItemDivider(getActivity()));
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false));
recyclerView.setAdapter(adapterItemsRecycler);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String itemName = editTxt.getText().toString();
saveIntoDatabase(itemName);
inputManager.hideSoftInputFromWindow(getView().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
editTxt.getText().clear();
}
});
return vistaADevolver;
}
@Override
public void onDestroy() {
super.onDestroy();
realm.close();
}
private void saveIntoDatabase(final String itemName) {
realm.executeTransactionAsync(new Realm.Transaction() {
@Override
public void execute(Realm bgRealm) {
Item item = bgRealm.createObject(Item.class);
item.setName(itemName);
item.setPoint(itemName);
item.setId(1);
}
}, new Realm.Transaction.OnSuccess() {
@Override
public void onSuccess() {
// Transaction was a success.
Log.v("database", "Stored ok");
}
}, new Realm.Transaction.OnError() {
@Override
public void onError(Throwable error) {
// Transaction failed and was automatically canceled.
Log.e("database", error.getMessage());
}
});
}
class ItemsListener
implements AdapterView.OnClickListener {
@Override
public void onClick(View view) {
Item itemTouched = results.get(recyclerView.getChildAdapterPosition(view));
EscuchadorInterface unEscuchador = (EscuchadorInterface) getActivity();
unEscuchador.itemSelected(itemTouched);
}
}
public interface EscuchadorInterface {
public void itemSelected(Item anItem);
}
}
// compile 'io.realm:android-adapters:2.0.0'
public class AdapterItemsRecycler
extends RealmRecyclerViewAdapter<Item, ItemViewHolder> {
private View.OnClickListener listener;
public AdapterItemsRecycler(OrderedRealmCollection<Item> itemList, View.OnClickListener listener) {
super(itemList, true);
this.listener = listener;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, final int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.inflate(R.layout.my_list_detail, parent, false);
view.setOnClickListener(listener);
ItemViewHolder itemViewHolder = new ItemViewHolder(view);
return itemViewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
Item item = getData().get(position);
ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
itemViewHolder.loadItem(item);
}
private static class ItemViewHolder
extends RecyclerView.ViewHolder {
private TextView itemText;
private ImageButton imageButton;
public ItemViewHolder(View view) {
super(view);
itemText = (TextView) view.findViewById(R.id.textViewItemNameTD);
imageButton = (ImageButton) view.findViewById(R.id.delete);
}
public void loadItem(Item item) {
itemText.setText(item.getName());
imageButton.setImageResource(R.drawable.trash);
}
public ImageButton getImageButton() {
return imageButton;
}
}
}
private void deleteFromDatabase(final String itemName) {
realm.executeTransactionAsync(new Realm.Transaction() {
@Override
public void execute(Realm bgRealm) {
Item item = bgRealm.where(Item.class).equalTo("name", itemName).findFirst();
if(item != null) {
item.deleteFromRealm();
}
}
}, new Realm.Transaction.OnSuccess() {
@Override
public void onSuccess() {
// Transaction was a success.
Log.v("database", "Delete ok");
}
}, new Realm.Transaction.OnError() {
@Override
public void onError(Throwable error) {
// Transaction failed and was automatically canceled.
Log.e("database", error.getMessage());
}
});
}