I need to retrieve single data from Firebase database. Where I have a list view contains id list. Whenever user clicks the listview i need to display the respective value field.
check screen shot of db
here is the code.
l1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
r2= FirebaseDatabase.getInstance().getReference().child("type").child("discord").child("ad");
r2.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
String name1;
name1=dataSnapshot.getValue().toString();
Toast.makeText(Main2Activity.this, name1, Toast.LENGTH_SHORT).show();
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
});
I need to execute the query
select value from table_name where id="01" ;
You need to change this line of code:
name1=dataSnapshot.getValue().toString();
with
name1=dataSnapshot.child("01").getValue(String.class);
Change the addChildEventListener to addValueEventListener.
For example:
r2.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String name1 = dataSnapshot.child("01").getValue(String.class);
Toast.makeText(Main2Activity.this, name1, Toast.LENGTH_SHORT).show();
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.e(TAG, "onCancelled", databaseError.toException());
}
});
Reference
Related
So I retrieved the data from Firebase database which is the "height". Whenever I add a height data, its supposed to plot it and connect to the previous height data.
So this is my series.
graph.addSeries(seriesheight);
seriesheight.setColor(Color.rgb(0,0,255));
seriesheight.setThickness(6);
seriesheight.setTitle("Height");
seriesheight.setDrawDataPoints(true);
seriesheight.setDataPointsRadius(8);
seriesheight.setOnDataPointTapListener(new OnDataPointTapListener() {
#Override
public void onTap(Series series, DataPointInterface dataPoint) {
Toast.makeText(getActivity(), dataPoint+ "\n" + date, Toast.LENGTH_SHORT).show();
}
});
and this is where I append the data
lastlastref.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
String heightu = dataSnapshot.child("height").getValue(String.class);
date = dataSnapshot.child("time_stamp").getValue(String.class);
if (heightu != null) {
height = Double.parseDouble(heightu);
seriesheight.appendData(new DataPoint(months, height), true, 100);
lastlastref.keepSynced(true);
}
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
this is the result
It only connects to the 2nd data. How can I connect all datapoints?
mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
#Override
public boolean onMarkerClick(com.google.android.gms.maps.model.Marker marker) {
// Toast.makeText(Map.this, marker.getPosition()+"", Toast.LENGTH_SHORT).show();
Query query = databaseReferenceMarkers.orderByChild("lat").equalTo(marker.getPosition().latitude);
query.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
Toast.makeText(Map.this, "test", Toast.LENGTH_SHORT).show();
dataSnapshot.getRef().removeValue();
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
return true;
}
});
Why am I not able to delete the marker?
onChildRemoved() -- no response.
The problem is that you're adding a value change listener, so onChildRemoved() will only be called once you remove the child, but you're removing it in the callback function.
Try it like this:
Query query = databaseReferenceMarkers.orderByChild("lat").equalTo(marker.getPosition().latitude);
query.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot child: dataSnapshot.getChildren()) { child.getRef().removeValue(); }
}
#Override
public void onCancelled(DatabaseError databaseError) {
Log.e(TAG, "onCancelled", databaseError.toException());
}
});
The query returns a collection of datasnapshots where there is a match. Then you'd need to iterate over them deleting every one of them.
The first 2 keys dont have child but others have them. I'm able to display the child elements when there is only one parent and I can display Admin/User details using data object model but how to display parent elements(Bright Kid Test & others) in Listview?
This is an image of Firebase Database:
Code:
listView = (ListView)findViewById(R.id.preschool_list);
adapter = new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line,list);
listView.setAdapter(adapter);
databaseReference = FirebaseDatabase.getInstance().getReference("Preschools");
databaseReference.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
String value = dataSnapshot.getValue(String.class);
list.add(value);
adapter.notifyDataSetChanged();
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
If there is only one child of preschools then it is displayed else no value is shown.
I've got the answer with datasnapshot.getChildren().
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot dsp : dataSnapshot.getChildren())
{
list.add(String.valueOf(dsp.getKey()));
adapter.notifyDataSetChanged();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
You want to display text Bright Kid LL, Bright Kid Mont, Bright Kid Test in list view, don't you? You can get them by getKey()
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot recipeSnapshot : dataSnapshot.getChildren()) {
String key = recipeSnapshot.getKey();
list.add(key);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
public void readUniversity(){
ChildEventListener uniListener = new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
//Log.d(LOG_TAG, dataSnapshot.getKey());
University uni = dataSnapshot.getValue(University.class);
universitieslist.add(uni); //Adding to an ArrayList of type University
//Log.d(LOG_TAG, universitieslist.size()+"is the size");
arrayofUniversities.add(uni.getName()); //Adding name of University to list
//Log.d(LOG_TAG, adapter.getCount() + " items");
//Log.d(LOG_TAG, arrayofUniversities.size()+" is the size");
adapter.notifyDataSetChanged();
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
};
DatabaseReference uniReference = database.getReference("note-retrieve/Universities");
uniReference.addChildEventListener(uniListener);
}
The code is pretty much self explanatory. I am using arrayofUniversities a list to populate a spinner so I need an adapter. I am populating the spinner with the names of the Universities
I am storing the University Objects in universitieslist
The problem I have is when I leave the readUniversity() method I lose every element in universitieslist and arrayofUniversities even though my spinner is populated with these.
Its very strange as the list should have the objects stored.
Also, I have my adapter at the very top of the code in onCreate().
Try this way. Hope it will work .. :)
private Arrylist<University > universityList = new ArryList<>();
private Arrylist<String> universitysName = new ArryList<>();
mDatabase.getReference().child("path")
.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
if (dataSnapshot != null) {
University mUniversity = dataSnapshot.getValue(University
.class);
universityList.add(mUniversity);
universitysName.add(mUniversity.getName);
}
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
The problem seems to be with the adapter, if you can see the logs but the adapter is not updating, then is because the adapter is not being notified the data set has changed
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
if (dataSnapshot != null) {
University mUniversity = dataSnapshot.getValue(University
.class);
universityList.add(mUniversity);
universitysName.add(mUniversity.getName);
//UPDATE YOUR ADAPTER HERE
//spinnerAdapter.notifyDataSetChanged();
}
}
But I think the real problem is the origin of your current problem: You are getting each child. This is a way to do it, but for this case where you need all the data first and when that is ready show the spinner with the elements to the user, you should better get all the list elements in one query.
database.getReference("note-retrieve/Universities")..addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
University mUniversity = dataSnapshot.getValue(University
.class);
universityList.add(mUniversity);
universitysName.add(mUniversity.getName);
//ONCE THIS IS DONE, THEN PASS THE ARRAY TO THE ADAPTER
}
//The loop here is over, so you can set the adapter with the full list of data/universities
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
I am trying to get UserID from one table(homeaccount) and get the user's info from another table(userinfo) using the user id. I tried to do it by the following way. But, it is overwriting the cardviews one on top of another.
databaseReference.child("homeaccount/"+globalSharedPrefs.getUserDetail("currenthome")+"/Users")
.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
String str_iteration_uid = dataSnapshot.getKey();
userQuery = databaseReference.child("userinfo").orderByChild("uid").equalTo(str_iteration_uid);
firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<HomeUsers, HomeUsersViewHolder>(
HomeUsers.class,
R.layout.cardview_manage_user,
HomeUsersViewHolder.class,
userQuery
){
#Override
protected void populateViewHolder(final HomeUsersViewHolder viewHolder, final HomeUsers model, int position) {
//viewHolder.setFirstName(model.getFirstName());
//viewHolder.setProfilePicture(model.getProfilePicture());
}
};
recyclerView.setAdapter(firebaseRecyclerAdapter);
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});