BAD STATE NO ELEMENT

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Emily Walton

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Feb 25, 2021, 7:18:28 AM2/25/21
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In this code I am trying to load a list from the database but the error shows bad state no element the first time I run it but when I hot reload the error disappears. Please help how can I solve this problem
List<ItemClass> getPathList(int id) {
print('Entered in get Path List');
int tempId = id;
List<ItemClass> tempPathList = List<ItemClass>();
List<ItemClass> tempo = List<ItemClass>();

while (tempId != 0) {
getItemFromId(id);
tempo = this.itemFromIdList;
THIS LINE CAUSING PROBLEM ItemClass temp = (tempo)?.first ?? [];<<<<<<<--------

tempPathList.add(temp);
tempId = temp.parent;

}

return tempPathList;
}

Emily Walton

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Feb 25, 2021, 7:22:19 AM2/25/21
to Flutter Development (flutter-dev)
Future<void> getItemFromId(int id) async {
  final Future<Database> dbFuture = databaseHelper.initializeDatabase();
  dbFuture.then((database) {
    Future<List<ItemClass>> itemListFromIdFuture =
        databaseHelper.getItemListFromId(id);

    itemListFromIdFuture.then((itemList) {
      this.itemFromIdList = itemList;

      //this.fullCount = itemList.length;
    });
  });
}
This is the code for getItemFromId which retrieves the itemList

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Suzuki Tomohiro

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Feb 25, 2021, 7:49:25 AM2/25/21
to Emily Walton, Flutter Development (flutter-dev)
Set a breakpoint at the line that causes the problem.

I think you will see “tempo” is an empty list when the problem happens.



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Suzuki Tomohiro

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Feb 25, 2021, 8:29:34 AM2/25/21
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What was the value of “tempo” when you use the breakpoint?
Both failed case and successful case.

On Thu, Feb 25, 2021 at 08:23 Emily Walton <whyth...@gmail.com> wrote:
yes i was suspecting that already but how do i solve this issue. Because when I hot reload, it gets filled up and hence no error.

Suzuki Tomohiro

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Feb 25, 2021, 9:09:05 AM2/25/21
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Good. You know the problem is. “tempo” was empty.

Would you check why it becomes empty?
Or, if it’s ok to be empty, how should it behave when it’s zero?


On Thu, Feb 25, 2021 at 09:01 Emily Walton <whyth...@gmail.com> wrote:
earlier the length was 0 when it was not working and when it works after hot reload then the length is 1

Benedicte Roussel

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Feb 25, 2021, 9:49:36 AM2/25/21
to Suzuki Tomohiro, Flutter Development (flutter-dev)

Doesn't t (tempo)?  Means it can be null while you want it to be !=0? 

Le jeu., févr. 25, 2021 à 15:09, Suzuki Tomohiro
<suz...@gmail.com> a écrit :

Emily Walton

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Feb 25, 2021, 10:58:01 PM2/25/21
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I thought (tempo)? will help to make tempo =[] if it is null. The main problem here is I want to update the-> this.itemFromIdList without reloading or resetting the state. 

Suzuki Tomohiro

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Feb 26, 2021, 8:30:04 AM2/26/21
to Emily Walton, Flutter Development (flutter-dev)
Null and an empty list are different. As per your observation, your error was caused by an empty list.

Bened

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Feb 26, 2021, 1:10:44 PM2/26/21
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tempo =[]  the time it loads

Bened

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Feb 26, 2021, 2:56:35 PM2/26/21
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think you should focus on how to write correct Future (async)

MANDEEP BIYANI

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Feb 27, 2021, 4:02:01 AM2/27/21
to Bened, Flutter Development (flutter-dev)
I want to know how i can make custom tabbar. Just ike this

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tababt.PNG

Benedicte Roussel

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Feb 27, 2021, 5:45:59 AM2/27/21
to MANDEEP BIYANI, Flutter Development (flutter-dev)
@biyani, you are in the thread of Emily. Try to open your own question. That looks like custom shapes with some icons stacked. 
please open your own thread

Benedicte Roussel

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Feb 27, 2021, 5:59:03 AM2/27/21
to MANDEEP BIYANI, Flutter Development (flutter-dev)
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