remove item from cart for a given product id - magento-1.7

Question

I am new in magento i have tried to remove items in cart when call this event checkout_cart_product_add_after when i try this code nothing can doing. any body help me. thanks.
$myProductId=20;
$product = Mage::getModel('catalog/product')->setStoreId(Mage::app()->getStore()->getId())->load($myProductId);
$quote = Mage::getSingleton('checkout/session')->getQuote();
$cartItems = $quote->getItemByProduct($product);
if ($cartItems) { $quote->removeItem($cartItems->getId())->save();}

Answer 1

The ItemId (ID of an item in the cart) is not the same as the ProductId of the product it represents. Try iterating through the items in the cart until you find the one with the ProductId you want to remove:
$cartHelper = Mage::helper('checkout/cart');
$items = $cartHelper->getCart()->getItems();
foreach ($items as $item) {
if ($item->getProduct()->getId() == $productId) {
$itemId = $item->getItemId();
$cartHelper->getCart()->removeItem($itemId)->save();
break;
}
}
Please try as described above.

Answer 2

Below code work for me you can try this you can call this function using ajax or post method put this function inside your controller and call it. pass the customer id and product it to it
public function removeCartAction()
{
$productId = trim($_POST['productId']);
$customer = trim($_POST['requesterId']);
if ($customer) {
$storeId = Mage::app()->getWebsite(true)->getDefaultGroup()->getDefaultStoreId();
// get quote table cart detail of all customer added
$quote = Mage::getModel('sales/quote')->setStoreId($storeId)->loadByCustomer($customer);
if ($quote) {
$collection = $quote->getItemsCollection(false);
if ($collection->count() > 0) {
foreach( $collection as $item ) {
if ($item && $item->getId()) {
$quote->removeItem($item->getId());
$quote->collectTotals()->save();
}
}
}
}
}
}

Answer 3

To remove item by specific item_id from cart(quote) you can use this:
$cart = Mage::getModel('checkout/session')->getQuote();
$cartHelper = Mage::helper('checkout/cart');
$items = $cart->getAllVisibleItems();
foreach($items as $item):
if($item->getItemId() == $id):
$itemId = $item->getItemId();
$cartHelper->getCart()->removeItem($itemId)->save();
break;
endif;
endforeach;

Answer 4

Execute this you will get the output
$product = $observer->getEvent()->getProduct();
$cart = Mage::getSingleton('checkout/cart');
foreach ($cart->getQuote()->getItemsCollection() as $_item) {
if ($_item->getProductId() == $productId) {
$_item->isDeleted(true);
//Mage::getSingleton('core/session')->addNotice('This product cannot be added to shopping cart.');
}
}