如何将产品添加到购物车并将其放入另一个活动中

Question

我通过listView中的jsonarray在我的Android应用程序中获取数据，当我点击listview项目时，它将打开另一个活动，其中包含该项目的详细信息，在此活动中我有一个按钮添加到购物车，当我点击这个按钮，产品在新的活动中进入购物车，但当我按下后退按钮添加新产品，再次点击添加到购物车按钮，我的第一个产品被第二个产品替换。我还为CartActivity添加了listView和listViewAdapter。

的 CartActivity

public class CartActivity extends AppCompatActivity implements View.OnClickListener {
String item_name;
String item_price;
String image;
ImageLoader imageLoader = new ImageLoader(this);
public int counter = 1;
public int sum = 0;
public int quantity;
ImageView ivAdd;
ImageView ivMinus;
TextView numberItem;
TextView txtTotalPrice;
Button btnAddCart;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cart);
    setTitle("Add to cart");
    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    Intent intent = getIntent();
    item_name = intent.getStringExtra("item_name");
    item_price = intent.getStringExtra("item_price");
    image = intent.getStringExtra("image");
    sum = Integer.parseInt(item_price);
    TextView itemName = (TextView) findViewById(R.id.tvName);
    TextView itemPrice = (TextView) findViewById(R.id.tvPrice);
    ImageView itemImage = (ImageView) findViewById(R.id.ivImage);
    txtTotalPrice = (TextView) findViewById(R.id.tvTotalTag);
    numberItem = (TextView) findViewById(R.id.tvNumberItem);
    ivMinus = (ImageView) findViewById(R.id.ivMinus);
    ivAdd = (ImageView) findViewById(R.id.ivAdd);
    btnAddCart = (Button) findViewById(R.id.btnCart);

    itemName.setText(item_name);
    itemPrice.setText(item_price);
    imageLoader.DisplayImage(image, itemImage);
    txtTotalPrice.setText(item_price);

    ivAdd.setOnClickListener(this);
    ivMinus.setOnClickListener(this);
    btnAddCart.setOnClickListener(this);
}

@Override
public void onClick(View v) {

    if (v == btnAddCart) {

        Bundle bundle=new Bundle();
        bundle.putString("name", item_name);
        bundle.putString("price", item_price);
        bundle.putInt("quantity", counter);
        bundle.putInt("total", sum);
        Intent intent = new Intent(SouthCartActivity.this, CheckoutActivity.class);
        intent.putExtras(bundle);
        startActivity(intent);
    }
}
}

的 CheckoutActivity

public class CheckoutActivity extends AppCompatActivity {
static ListView listView;
CheckoutAdapter adapter;
String item_name[];
String item_price[];
int item_quantity[];
int item_total[];

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_checkout);
    setTitle("Checkout");
    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    Bundle bundle = getIntent().getExtras();
    item_name = new String[]{bundle.getString("name")};
    item_price = new String[]{bundle.getString("price")};
    item_quantity = new int[]{bundle.getInt("quantity")};
    item_total = new int[]{bundle.getInt("total")};

    adapter = new CheckoutAdapter(this, item_name, item_price, item_quantity, item_total);
    listView = (ListView) findViewById(R.id.listView);
    listView.setAdapter(adapter);
}
}