我有以下代码,我试图计算销售和支出之间的差异。我必须以不同方式查询数据库才能实现这一目标。我正在寻找一种简单的方法来实现这一目标,或者通过以下代码实现相同的更好方法:
dref= dref.child("KatakaExpenditure");
dreff= dref.child("KatakaSales");
dref.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot snapshot) {
int totalAmount = 0;
for (DataSnapshot postSnapshot : snapshot.getChildren()) {
DogExpenditure dogExpenditure = postSnapshot.getValue(DogExpenditure.class);
totalAmount += dogExpenditure.getAmount();
}
textView4.setText("Your total expenses for Kataka Unit is:" +Integer.toString(totalAmount));
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
public void onCancelled(FirebaseError firebaseError) {
System.out.println("The read failed: " + firebaseError.getMessage());
}
});
dreff.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot snapshot) {
int totalAmountt = 0;
for (DataSnapshot postSnapshot : snapshot.getChildren()) {
DogExpenditure dogExpenditure = postSnapshot.getValue(DogExpenditure.class);
totalAmountt += dogExpenditure.getAmount();
}
textView4.setText("Your total expenses for Kataka Unit is:" +Integer.toString(totalAmountt));
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
public void onCancelled(FirebaseError firebaseError) {
System.out.println("The read failed: " + firebaseError.getMessage());
}
});
textView4.setText("Your total expenses for Kataka Unit is:" +Integer.toString(totalAmountt));
int profit = totalAmountt - totalAmount;
Where totalAmount is the **dref= dref.child("KatakaExpenditure");
** and totalAmountt is **dreff= dref.child("KatakaSales");**