我知道我知道这可能是这里几个问题的重复，但是，嘿，这些解决方案还没有奏效。所以我真的需要建议。
一直试图使用firebase管理我的listview，但无济于事。
我已经尝试了几个教程，但没有一个解决了我的问题。
我有一个listview，我试图从Firebase填充。我创建了custom adapter并在那里添加了childEventListeners。最后，我将adapter附加到我的listview。我的firebase database中有几个项目，但只有最后一个项目显示在我的listview中。我想显示所有这些项目。
FireBaseListAdapter.java：
public abstract class FireBaseListAdapter extends ArrayAdapter<SaleModel> {
Activity activity;
// Setup our Firebase mFirebaseRef
DatabaseReference mRef;
private SaleModel model;
private String mUsername;
private LayoutInflater mInflater;
private List<SaleModel> mModels;
private List<String> mKeys;
private ChildEventListener mListener;
private ViewGroup viewGroup;
private LinearLayout wrapper;
public FireBaseListAdapter(DatabaseReference mRef, Activity activity) {
super(activity, android.R.layout.simple_list_item_1);
this.activity = activity;
this.mRef = mRef;
this.mUsername = mUsername;
mInflater = activity.getLayoutInflater();
mModels = new ArrayList<SaleModel>();
mKeys = new ArrayList<String>();
// Look for all child events. We will then map them to our own internal ArrayList, which backs ListView
mListener = this.mRef.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
Map<String, Object> newPost =
(Map<String, Object>) dataSnapshot.getValue();
model = new SaleModel(newPost.get("name").toString(),
newPost.get("attendant_name").toString(),
newPost.get("created_at").toString());
String key = dataSnapshot.getKey();
// Insert into the correct location, based on previousChildName
if (previousChildName == null) {
mModels.add(0, model);
mKeys.add(0, key);
} else {
int previousIndex = mKeys.indexOf(previousChildName);
int nextIndex = previousIndex + 1;
if (nextIndex == mModels.size()) {
mModels.add(model);
mKeys.add(key);
} else {
mModels.add(nextIndex, model);
mKeys.add(nextIndex, key);
//showNotification(model);
}
}
notifyDataSetChanged();
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
// One of the mModels changed. Replace it in our list and name mapping
String key = dataSnapshot.getKey();
Map<String, Object> newPost =
(Map<String, Object>) dataSnapshot.getValue();
SaleModel newModel = new SaleModel(newPost.get("message").toString(), newPost.get("author").toString(), newPost.get("created_at").toString());
int index = mKeys.indexOf(key);
mModels.set(index, newModel);
notifyDataSetChanged();
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
// A model was removed from the list. Remove it from our list and the name mapping
String key = dataSnapshot.getKey();
int index = mKeys.indexOf(key);
mKeys.remove(index);
mModels.remove(index);
notifyDataSetChanged();
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) {
// A model changed position in the list. Update our list accordingly
String key = dataSnapshot.getKey();
Map<String, Object> newPost =
(Map<String, Object>) dataSnapshot.getValue();
SaleModel newModel = new SaleModel(newPost.get("message").toString(), newPost.get("author").toString(), newPost.get("created_at").toString());
int index = mKeys.indexOf(key);
mModels.remove(index);
mKeys.remove(index);
if (previousChildName == null) {
mModels.add(0, newModel);
mKeys.add(0, key);
} else {
int previousIndex = mKeys.indexOf(previousChildName);
int nextIndex = previousIndex + 1;
if (nextIndex == mModels.size()) {
mModels.add(newModel);
mKeys.add(key);
} else {
mModels.add(nextIndex, newModel);
mKeys.add(nextIndex, key);
}
}
notifyDataSetChanged();
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.e("FireBaseListAdapter", "Listen was cancelled, no more updates will occur");
}
});
}
public void cleanup() {
// We're being destroyed, let go of our mListener and forget about all of the mModels
mRef.removeEventListener(mListener);
mModels.clear();
mKeys.clear();
}
@Override
public int getCount() {
return mModels.size();
}
@Override
public SaleModel getItem(int i) {
return mModels.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
SaleModel comment = getItem(position);
int type = getItemViewType(position);
// Map a Chat object to an entry in our listview
String author = comment.getName();
String attendant_name = comment.getAttendant_name();
String created_at = comment.getCreated_at();
// If the message was sent by this user, color it differently
LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService
(this.activity.getApplicationContext().LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.itemview, parent, false);
((TextView) row.findViewById(R.id.attname)).setText(attendant_name);
((TextView) row.findViewById(R.id.c_name)).setText(author);
((TextView) row.findViewById(R.id.updated_at)).setText(created_at);
return row;
}
}
SaleModel.java：
public class SaleModel {
//obviously there's a lot of things i'm not using here, so ignore these
String id, business_id, attendant_id, attendant_name, product_id,
customer_id, customer_first_name, code,
customer_last_name, customer_image, uid,
reader_id, price, quantity, name, image,
created_at, deleted_at, offlineTag, updated_at, svg;
public SaleModel() {
}
public SaleModel(String name, String attendant_name, String created_at) {
this.name = name;
this.attendant_name = attendant_name;
this.created_at = created_at;
}
//getters and setters
public String getAttendant_name() {
return attendant_name;
}
public void setAttendant_name(String attendant_name) {
this.attendant_name = attendant_name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCreated_at() {
return created_at;
}
public void setCreated_at(String created_at) {
this.created_at = created_at;
}}
这就是我在片段中使用它的方式：
@Override
public void onStart() {
super.onStart();
FirebaseDatabase ref = FirebaseDatabase.getInstance().getReference().child("sales");
setUpAdapter();
final FireBaseListAdapter mChatListAdapter = new FireBaseListAdapter(ref, parentActivity) {
@Override
public void cleanup() {
super.cleanup();
}
};
listView.setAdapter(mChatListAdapter);
mChatListAdapter.registerDataSetObserver(new DataSetObserver() {
@Override
public void onChanged() {
super.onChanged();
listView.setSelection(mChatListAdapter.getCount() - 1);
}
});
}
我的数据结构示例：
{
"-KMjcAb5O2MOx_WrofUT" : {
"attendant_id" : "93",
"business_id" : "9",
"code" : "9.146860413464",
"created_at" : "2016-07-15 08:32:10",
"customer_first_name" : "Unidentified",
"customer_id" : "10",
"customer_last_name" : "",
"image" : "",
"name" : "Black Forest Cake 2kg",
"price" : "3500.0",
"product_id" : "59",
"quantity" : "1",
"reader_id" : "93",
"uid" : ""
},
"-KMjcAb8EQi3ujTpoJG1" : {
"attendant_id" : "93",
"business_id" : "9",
"code" : "9.146860413465",
"created_at" : "2016-07-15 08:32:10",
"customer_first_name" : "Unidentified",
"customer_id" : "10",
"customer_last_name" : "",
"image" : "",
"name" : "Black Forest Cake 2kg",
"price" : "3500.0",
"product_id" : "59",
"quantity" : "1",
"reader_id" : "93",
"uid" : ""
}}
答案 0 :(得分：1)
您需要循环代码的这一部分，如下所示。希望这会对你有所帮助。
Map < String, Object > newPost =
(Map < String, Object > ) dataSnapshot.getValue();
for (Object posts: newPost.values()) {
Map < String, Object > postMap = (Map < String, Object > ) posts;
model = new SaleModel(postMap.get("name").toString(),
postMap.get("attendant_name").toString(),
postMap.get("created_at").toString());
String key = dataSnapshot.getKey();
// Insert into the correct location, based on previousChildName
if (previousChildName == null) {
mModels.add(0, model);
mKeys.add(0, key);
} else {
int previousIndex = mKeys.indexOf(previousChildName);
int nextIndex = previousIndex + 1;
if (nextIndex == mModels.size()) {
mModels.add(model);
mKeys.add(key);
} else {
mModels.add(nextIndex, model);
mKeys.add(nextIndex, key);
//showNotification(model);
}
}
}