Syncing the data in arrays between activities

Question

I am making a food order app. There is a full page ListView on my main page called MenuActivity and there is a Button when I press it, it will intent to the CartActivity page.

I have arrays food for food name, imgID for food images, butPlus butMinus to adjust the amount of food and amount to keep the amount of each food with an initial value of 0.

I have a method called addAmount , minusAmount in MenuAcitivity that will increase, decrease the amount. It is called by an Adapter of this class.

public static void addAmount(int position) {
    amount[position] += 1;
}

Going to CartActivity, I used this to pass all my values.

public void goToCart(MenuItem menuItem) {
    Intent in = new Intent(MenuActivity.this, CartActivity.class);
    in.putExtra("list", amount);
    in.putExtra("imgID", imgID);
    in.putExtra("nameList", food);
    startActivity(in);
}

to receive the values I created new ArrayList in CartActivity to get the data of the food that the amount in not zero.

        // add components to array lists
        // addList, removeList are methods to add,remove in my new ArrayList created in this class
    for (int i = 0; i < amountList.length; i++) {
        if (amountList[i] != 0) {
            if (!foodListFinal.contains(foodList[i]))
                addList(amountList[i], foodList[i], imgID[i]);
        } else if (amountList[i] == 0 && !foodListFinal.isEmpty()) {
            if (foodListFinal.contains(foodList[i])) {
                index = foodListFinal.indexOf(foodList[i]);
                removeList(amountList[index], foodList[index], imgID[index]);
            }
        }
    }

Also, I have a method called addAmount , minusAmount in CartAcitivity that will increase, decrease the amount just like in the MenuActivity. It is called by an Adapter of this class which is not the same one with MenuActivity.

public static void addAmount(int position) {
    int newAmount = (amountListFinal.get(position)) + 1;
    amountListFinal.set(position, newAmount);
}

public static void minusAmount(int position) {
    int newAmount = (amountListFinal.get(position)) - 1;
    amountListFinal.set(position, newAmount);
}

Here is my problem..

When I decrease amount in the CartActivity to 0 and I went back to MenuActivity it correctly says 0, but if I switch to CartActivity again the app crashes with an error saying index out of bound.

Please help me with this, or is there any better way to do this please enlighten me. Thank you

score 0 · Answer 1 · answered Nov 23 '17 at 06:46

0

for which array caused this error : " saying index out of bound." , foodList or amountList array ? It's gonna help you

answered Nov 23 '17 at 06:46

Farrokh Shahriari

377
2
10

Thanks for answering!! I got it worked out now :) – Triniel Nov 23 '17 at 15:33

ROHIT LIEN · Answer 2 · 2017-11-24T12:35:00.623

0

I would suggest to use secondary storage to store your changes. Also passing whole array to another activity is not recommended.Use any database to insert change in it and then in cart activity retrieve all data. This way ,you can achieve same state of amount in various objects.

edited Nov 24 '17 at 12:35

answered Nov 23 '17 at 07:10

ROHIT LIEN

497
3
8

Thank you!! I think I'm getting it to work using SQLite :D – Triniel Nov 23 '17 at 15:32

Syncing the data in arrays between activities

2 Answers2