Last week I started learning Android as I needed to create an application for one of the projects at Uni.
The application is a simple barcode/QRcode scanner and it should scan the code, compare its result with the database (I'm using Firebase) and either return other data from database if the barcode is found or ask the user if he wants to add the barcode to the database if it's not found.
I thought the easiest way to do it would be to use AlertDialog, but the app crashes every single time I scan the code.
I debugged the app and checked the Logcat, what I get is:
You need to use a Theme.AppCompat theme (or descendant) with this activity.
This is exactly where I get the error and where I wanted to use AlertDialog - based on the value in the variable details.
private BarcodeCallback callback = new BarcodeCallback() {
@Override
public void barcodeResult(final BarcodeResult result) {
barcodeView.decodeSingle(callback);
dbRef.child("Items").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Iterator<DataSnapshot> item = dataSnapshot.getChildren().iterator();
Boolean isFound = false;
while (!isFound || item == null) {
DataSnapshot i = item.next();
String check = i.child("ID").getValue().toString();
if (result.getText().equals(check)) {
isFound = true;
details = "Consumption: " + i.child("Consumption").getValue().toString()
+ "\nCost: " + i.child("Cost").getValue().toString()
+ "\nName: " + i.child("Name").getValue().toString();
} else {
details = "Not found";
}
}
new AlertDialog.Builder(getApplicationContext())
.setMessage("This is just an example for the purpose of the question.")
.create()
.show();
}
I get the error exactly on the line with .show();.
In the previous posts I found that you can't display AlertDialog in this place, and you need to use runOnUiThread function or Handler, none of those options worked for me, and I was getting the error in the same place.
Do you guys have any advice or suggestions?
Also, I'm sorry for the way this post looks like or for any missing but required information. I know it's not an excuse, but this is my first post here.
Thanks in advance for any replies.
