我有一个书籍 ListView ，我通过单击项目及其作品来更新 ListView ，但是我有重复的项目，旧的和新的。在我的数据库中我只有新数据。我怎样才能修改我的 ListView ？我正在使用 FireBase 数据库。
更新我的 Activity 来源:
public class ListOfMyBookActivity extends AppCompatActivity {
//The elements are initialized here
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_of_my_book);
listView = (ListView) findViewById(R.id.list_book);
feedItems = new ArrayList<Book>();
dataBD= FirebaseDatabase.getInstance();
dataBaseD=FirebaseDatabase.getInstance();
updateDB=FirebaseDatabase.getInstance();
ref = dataBD.getReference("books");
refdelete=dataBaseD.getReference("books");
refUpdate=updateDB.getReference("books");
auth = FirebaseAuth.getInstance();
mDatabase = FirebaseDatabase.getInstance().getReference("books");
ref.orderByChild("date_creation").limitToLast(10).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
List<String> list = new ArrayList<String>();
for (DataSnapshot dataSnap : dataSnapshot.getChildren()) {
Book valueBook = dataSnap.getValue(Book.class);
keyId = dataSnap.getKey();
String userBd = valueBook.getId_user();
if (userBd.equalsIgnoreCase(id_user)) {
String titreLivreToDisplay = valueBook.getNom_livre();
String descLivreToDisplay = valueBook.getDesc_livre();
String prixLivreToDisplay = valueBook.getPrix_livre();
String timeToDisplay = valueBook.getDate_creation();
String filePathToDiplay = valueBook.getChemin_image();
String villeToDisplay = valueBook.getVille_livre();
String typeAnnToDisplat = valueBook.getType_annonce_selected();
String bookid = valueBook.getId_book();
item = new Book();
item.setNom_livre(titreLivreToDisplay);
item.setDesc_livre(descLivreToDisplay);
item.setPrix_livre(prixLivreToDisplay);
item.setDate_creation(timeToDisplay);
item.setChemin_image(filePathToDiplay);
item.setVille_livre(villeToDisplay);
item.setType_annonce_selected(typeAnnToDisplat);
item.setId_book(bookid);
item.setKeyIdNode(keyId);
feedItems.add(item);
}
Collections.reverse(feedItems);
listAdapter = new MyBookListAdapter(ListOfMyBookActivity.this, feedItems);
listView.setAdapter(listAdapter);
listView.setOnItemClickListener(myClickListener);
listAdapter.notifyDataSetChanged();
}}
});
}
public AdapterView.OnItemClickListener myClickListener = new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> arg0, View arg1,
final int position, long arg3) {
deleteItem = position;
// The AlertDialog is created programmatically
AlertDialog.Builder alert = new AlertDialog.Builder(arg1.getContext());
nameBookEdtDlg.setText(nom);
descBookEdtDlg.setText(desc);
prixBookEdtDlg.setText(prix);
alert.setPositiveButton("Update ",
new DialogInterface.OnClickListener()
{
public void onClick (DialogInterface dialog,
int whichButton){
Query query = refUpdate.orderByChild("id_book").equalTo(bookID);
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
prixSt=prixBookEdtDlg.getText().toString();
descSt=descBookEdtDlg.getText().toString();
namSt=nameBookEdtDlg.getText().toString();
Map<String, Object> result = new HashMap<String, Object>();
result.put("nom_livre", namSt);
result.put("desc_livre", descSt);
result.put("prix_livre", prixSt);
result.put("date_creation", currentDateandTimeUpdate);
refUpdate.child(keyId).updateChildren(result);
listAdapter.notifyDataSetChanged();
} });
AlertDialog alertDialog = alert.create();
try{alertDialog.show();} } };}
}
}
适配器:
public class MyBookListAdapter extends BaseAdapter {
public MyBookListAdapter( ListOfMyBookActivity listMyBooks, List<Book> feedItemsBooks) {
this.activity = listMyBooks;
this.feedItemsBooks = feedItemsBooks;
}
@Override
public int getCount() {
return feedItemsBooks.size();
}
@Override
public Object getItem(int location) {
return feedItemsBooks.get(location);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, final ViewGroup parent) {
final int pos = position;
if (inflater == null) {
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
if (convertView == null) {
convertView = inflater.inflate(R.layout.feed_list_item, null);
}
storageDisplayImg = FirebaseStorage.getInstance();
auth = FirebaseAuth.getInstance();
FirebaseUser userConnect = auth.getCurrentUser();
String id_user = userConnect.getUid();
mFirebaseInstance = FirebaseDatabase.getInstance();
mFirebaseDatabase = mFirebaseInstance.getReference("books");
final ImageView profilePic = (ImageView) convertView.findViewById(R.id.book_picture_display_myBook);
name = (TextView) convertView.findViewById(R.id.name_book_display_myBook);
TextView timestamp = (TextView) convertView.findViewById(R.id.timestamp_myBook);
statusMsg = (TextView) convertView.findViewById(R.id.desc_display_myBook);
prix = (TextView) convertView.findViewById(R.id.prix_display_myBook);
TextView ville = (TextView) convertView.findViewById(R.id.ville_display_myBook);
TextView typeCat = (TextView) convertView.findViewById(R.id.type_ann_to_display_myBook);
Book item = feedItemsBooks.get(position);
idLivreListAdapter=item.getId_book();
name.setText(item.getNom_livre());
if (!TextUtils.isEmpty(item.getDate_creation())) {
timestamp.setText(item.getDate_creation());
timestamp.setVisibility(View.VISIBLE);
} else {
timestamp.setVisibility(View.GONE);
}
if (!TextUtils.isEmpty(item.getDesc_livre())) {
statusMsg.setText(item.getDesc_livre());
statusMsg.setVisibility(View.VISIBLE);
} else {
statusMsg.setVisibility(View.GONE);
}
if (!TextUtils.isEmpty(item.getType_annonce_selected())) {
typeCat.setText(item.getType_annonce_selected());
typeCat.setVisibility(View.VISIBLE);
} else {
typeCat.setVisibility(View.GONE);
}
if (item.getPrix_livre() != null) {
prix.setText(item.getPrix_livre() + " DH");
prix.setVisibility(View.VISIBLE);
} else {
prix.setVisibility(View.GONE);
}
if (item.getVille_livre() != null) {
ville.setText(item.getVille_livre());
ville.setVisibility(View.VISIBLE);
} else {
ville.setVisibility(View.GONE);
}
storageRef = storageDisplayImg.getReferenceFromUrl(item.getChemin_image());
Log.e(" ", " storageRef " + storageRef.toString());
if (item.getChemin_image() != null && id_user != null) {
Glide.with(convertView.getContext())
.using(new FirebaseImageLoader())
.load(storageRef)
.into(profilePic);
profilePic.setVisibility(View.VISIBLE);
} else {
profilePic.setVisibility(View.GONE);
}
return convertView;
}
}
我的问题没有重复我尝试了建议的解决方案，但它不起作用。
最佳答案
不确定这是否是您的问题，但大多数 firebase 代码并非都是必需的...
请注意，您调用了 getNom_livre(和其他)，然后使用完全相同的值调用了 setNom_livre(和其他)？
当您已经拥有一本新书时，您也可以制作一本。
Book valueBook = dataSnap.getValue(Book.class); // This is a Book keyId = dataSnap.getKey(); String userBd = valueBook.getId_user(); if (userBd.equalsIgnoreCase(id_user)) { String titreLivreToDisplay = valueBook.getNom_livre(); ... item = new Book(); // Why do you need a new one? item.setNom_livre(titreLivreToDisplay); ... feedItems.add(item); }
首先，您应该将它移到 firebase 方法之前。无需在每次数据更新时重新创建适配器。
listAdapter = new MyBookListAdapter(ListOfMyBookActivity.this, feedItems);
listView.setAdapter(listAdapter);
listView.setOnItemClickListener(myClickListener);
ref.orderByChild("date_creation")...
but i have duplicate item , the old one and the new one
您只需清除适配器即可删除旧数据并添加新数据
ref.orderByChild("date_creation")
.limitToLast(10)
.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
// Remove old data
feedItems.clear();
// Add new data
for (DataSnapshot dataSnap : dataSnapshot.getChildren()) {
Book valueBook = dataSnap.getValue(Book.class);
keyId = dataSnap.getKey();
String userBd = valueBook.getId_user();
if (userBd.equalsIgnoreCase(id_user)) {
valueBook.setKeyIdNode(keyId);
feedItems.add(valueBook);
}
}
Collections.reverse(feedItems);
listAdapter.notifyDataSetChanged(); // Tell adapter of new data
关于android - 更新数据库后更新listView？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43452589/