我想从firebase数据库中读取特定数据.我目前正在做的是这里.
DatabaseReference database = FirebaseDatabase.getInstance().getReference();
DatabaseReference myRef = database.child("profiles/");
myRef.child(phoneNo).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
user = dataSnapshot.getValue(User.class);
}
@Override
public void onCancelled(DatabaseError databaseError) {}
});
写入DB的方法
public void writeToDBProfiles(Object data,String phoneNo) {
DatabaseReference database = FirebaseDatabase.getInstance().getReference();
DatabaseReference myRef = database.child("profiles/" + phoneNo);
myRef.setValue(data);
}
但它返回null …任何帮助将不胜感激.
解决方法
如果您想使用电话号码获取特定数据,那么您可以使用这样的查询
DatabaseReference database = FirebaseDatabase.getInstance().getReference();
DatabaseReference ref = database.child("profiles");
Query phoneQuery = ref.orderByChild(phoneNo).equalTo("+923336091371");
phoneQuery.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot singleSnapshot : dataSnapshot.getChildren()){
user = singleSnapshot.getValue(User.class);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.e(TAG,"onCancelled",databaseError.toException());
}
});
我认为这是最好的方法.
