How to get the arraylist out android studio

Question

I am unable to get my ArrayList out when it's on a different page. I would like to get the ArrayList out Android Studio.

This is CartActivity class:

public class CartActivity extends AppCompatActivity {
    private ArrayList<CartItem> cartList;
    ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cart);

        listView = (ListView) findViewById(R.id.listView);
        CartAdapter adapter = null;
        cartList = new ArrayList<>();
        adapter = new CartAdapter(this, R.layout.adapter_cart_item, cartList);
        listView.setAdapter(adapter);
    }
}

This is ProductActivity class. It's where the data is being stored into the ArrayList:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_product);
    myDB = new DatabaseHelper(ProductActivity.this);
    textViewPrice = (TextView) findViewById(R.id.textViewPrice);
    textViewInfo = (TextView) findViewById(R.id.textViewInfo);
    textViewName = (TextView) findViewById(R.id.textViewName);
    ivProduct = (ImageView) findViewById(R.id.ivProduct);
    btnAddToCart = (Button) findViewById(R.id.btnAddToCart);
    spinnerQuantity = (Spinner) findViewById(R.id.spinnerQuantity);


    Intent in = getIntent();
    Bundle b = in.getExtras();
    userID = b.getString("userID");
    productID = b.getInt("productID");
    Cursor results = myDB.checkProduct();
    if (results.getCount() == 0) {
        Toast.makeText(getApplicationContext(), "Error: no data found!",
                Toast.LENGTH_SHORT).show();
        return;
    } else {
        StringBuffer buffer = new StringBuffer();
        while (results.moveToNext()) {
            id = results.getInt(0);
            name = results.getString(1);
            price = results.getString(2);
            info = results.getString(4);
            quantity = Integer.parseInt(results.getString(5));
            image = results.getBlob(6);
            if (id == productID) {
                textViewName.setText(name);
                textViewInfo.setText(info);
                textViewPrice.setText("S$" + price);

                int[] quantityValues = new int[quantity + 1];
                int counter = 0;
                for (int i = 0; i < quantityValues.length; i++) {
                    quantityValues[i] = counter;
                    counter++;
                    quantityList.add(Integer.toString(quantityValues[i]));

                }
                Bitmap bitmap = BitmapFactory.decodeByteArray(image, 0, image.length);
                ivProduct.setImageBitmap(bitmap);


                ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, quantityList);
                adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

                spinnerQuantity.setAdapter(adapter);
            }
        }
    }
}

public void addCart(View v) {
    cartList.add(new CartItem(name, price,spinnerQuantity.getSelectedItem().toString(), image, id));

    Intent productListIntent = new Intent(this, CartActivity.class);
    startActivity(productListIntent);

}

Why would you expect, in general, that variables in one activity would be accessible from another activity? — Tim Biegeleisen, Jun 19 '17 at 11:14
you should pass array list from Activity A to B, after that you able to add new item to that, see this ref: https://stackoverflow.com/a/21250407/4146722 — Pratik Tank, Jun 19 '17 at 11:20
isn't variables in one activity be accessible from another activity? — KUROYUKI, Jun 19 '17 at 11:22

score 1 · Answer 1 · answered Jun 19 '17 at 11:35

1

You should impliment Serializable in CartItem class and then pass from ProductActivity to CartActivity . Like this :

ProductActivity class.

Intent productListIntent= new Intent(this, CartActivity .class);
  productListIntent.putExtra("cartlist", ArrayList<CartItem>mcartItem);
startActivity(productListIntent);

and in CartActivity class

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cart);
      ArrayList<CartItem> mycart= new ArrayList<CartItem>();
          mycart= (ArrayList<CartItem>)getIntent().getSerializableExtra("cartlist");
     listView = (ListView) findViewById(R.id.listView);
        CartAdapter adapter = null;
        adapter = new CartAdapter(this, R.layout.adapter_cart_item, mycart);
        listView.setAdapter(adapter);
    }

answered Jun 19 '17 at 11:35

PRIYA PARASHAR

777
4
15

have you implement Serializable in CartItem class? – PRIYA PARASHAR Jun 19 '17 at 12:59
I have just tried but there is systex error productListIntent.putExtra("cartlist", ArrayListmcartItem); – KUROYUKI Jun 19 '17 at 13:02
I have just implemented Serializable in CartItem class. – KUROYUKI Jun 19 '17 at 13:03
you may try "productListIntent.putExtra("cartlist", cartList);" this. – PRIYA PARASHAR Jun 19 '17 at 13:05
Thank you for all of your help after I tried productListIntent.putExtra("cartlist", cartList); it didnt have any systex error anymore but it still didn't work. but after I run an update it just suddenly work. – KUROYUKI Jun 19 '17 at 14:55
If the above code is helpful for your problem then please accept this answer because other person also have to face the same problem soo this solution may be helpful for them. – PRIYA PARASHAR Jun 20 '17 at 05:29

score 0 · Answer 2 · answered Jun 19 '17 at 11:49

You have to pass your list of your data via intent(as Intent is a message passing Object) From ! activity to another activity. For that you have to make that class Parcable or Serializable . How to make a class Parcable in andriod studio read this answer. Then put thah class into the intent that you are passing to startActivity() method like

intent.putParcelableArrayListExtra("key",your_list);

or

 intent.putExtra("key",your_class)// incase of single object

then get it to the onCreate() method of second activity like

getIntent().getParcelableArrayListExtra("your_key")

or

getIntent().getParcelableExtra()//  incase of single object

Hope it will help your

score 0 · Accepted Answer · answered Jun 19 '17 at 13:42

0

It's not the best practice, but you can make your arrayList

public static ArrayList list;

Then you can access it from ather activity using {class_name}.list

answered Jun 19 '17 at 13:42

igor

716
1
9
27

Thanks for your help – KUROYUKI Jun 19 '17 at 16:55

How to get the arraylist out android studio

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