此 Firebase 数据库结构：
在此输入图像描述 https://i.stack.imgur.com/sIjX8.png
这是我的设备类别：
public class Device {
private String title;
private Map<String,Counters> CounterNumber;
private Counters counters;
public void setCounter(Map<String,Counters> CounterNumber){
this.CounterNumber=CounterNumber;
}
public Map<String,Counters> getCounter(){
return CounterNumber;
}
public Counters getCounters(){
return counters;
}
public void setCounters(Counters counters){
this.counters=counters;
}
public Device(){
}
public Device(String title){
this.title=title;
}
public String getTitle(){
return title;
}
public void setTitle(String title){
this.title=title;
}
}
Second class is my nested object I think
二等计数器班我的问题是我不知道如何阅读Counter来自数据库的对象FirebaseUI and RecycleView.
public class Counters implements Serializable {
private String countername;
private String counternumber;
public Counters (){
}
public Counters(String counternumber,String countername){
this.counternumber=counternumber;
this.countername=countername;
}
public String getCounterName() {
return countername;
}
public void setCounterName(String counterName) {
this.countername = countername;
}
public String getCounterNumber() {
return counternumber;
}
public void setCounterNumber(String counternumber) {
this.counternumber = countername;
}
}
这是我的 HomeActivity 这里从 firebase 对象读取
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
recyclerView=(RecyclerView)view.findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
firebaseDatabase=FirebaseDatabase.getInstance();
databaseReference=firebaseDatabase.getReference();
mDevice=new ArrayList<Device>();
mdevices=new Device();
databaseReference.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
}
@Override
public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
if (dataSnapshot != null && dataSnapshot.getValue() != null) {
try {
for (DataSnapshot eventSnapshot : dataSnapshot.getChildren()) {
ArrayList<String> counterse= (ArrayList<String>) eventSnapshot.getValue();
Log.e(TAGE, counterse.toString());
Device device = eventSnapshot.getValue(Device.class);
String id = eventSnapshot.getKey();
Counters counters = eventSnapshot.child(id).getValue(Counters.class);
device.setCounters(counters);
mDevice.add(device);
}
} catch (Exception ex) {
Log.e(TAG, ex.getMessage());
}
}
displayDevices();
}
@Override
public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
return view;
}
private void displayDevices(){
options=
new FirebaseRecyclerOptions.Builder<Device>()
.setQuery(databaseReference.child("devices").orderByChild("user_id").equalTo(userid),Device.class).build();
adapter=
new FirebaseRecyclerAdapter<Device, MyRecyclerViewHolder>(options) {
@Override
protected void onBindViewHolder(@NonNull MyRecyclerViewHolder holder, int position, @NonNull Device model) {
mdevices=mDevice.get(position);
holder.txt_title.setText(model.getTitle());
holder.txt_counter.setText(mdevices.getCounters().getCounterNumber());
Log.i(TAG,mdevices.getCounters().getCounterNumber());
}
@NonNull
@Override
public MyRecyclerViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View itemView= LayoutInflater.from(getContext()).inflate(R.layout.device_list,parent,false);
return new MyRecyclerViewHolder(itemView);
}
};
adapter.startListening();
recyclerView.setAdapter(adapter);
}
@Override
public void onStart() {
adapter.startListening();
super.onStart();
}
@Override
public void onStop() {
super.onStop();
if(adapter != null) {
adapter.stopListening();
}
}
这是我的错误代码在此输入图像描述 https://i.stack.imgur.com/DKJfi.png
