RecyclerView项的属性在使用DataBinding时自动更改

问题描述 投票：0回答：1

我正在尝试使用DataBinding（在Java中）构建没有任何设计模式的简单任务。场景是有一个RecyclerView，其中的项目/产品是从HardCoded列表中绑定的。每当用户单击任何item时，都应在左侧（空白）显示具有默认值（属性）的特定项目。现在，当用户单击左侧的item时，其属性（数量，价格等）应更改（仅在该左侧的框中）。现在一切都很好。问题在于，更改左侧项目的属性后，每当用户再次单击同一item（他之前单击过）时，它都会在item上显示更改后的值。左边。但是我希望再次单击它应该显示具有默认值的item。我已经附上了所有的课程和屏幕截图。如果我做错了，请识别我。

Product.java

public class Product {
private String title;
private String price;
private String image;
private String quantity;
private String discount;

public Product(String title, String price, String image, String quantity, String discount) {
    this.title = title;
    this.price = price;
    this.image = image;
    this.quantity = quantity;
    this.discount = discount;
}

//Getters and Setters
}

MainTestActivity.java

public class MainTestActivity extends AppCompatActivity implements ProductsListAdapter.ProductItemClickListener{

ActivityMainTestingBinding binding;
private Product myCurrentProduct;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    binding = DataBindingUtil.setContentView(this, R.layout.activity_main_testing);

    getItems();
}



private void getItems(){

    List<Product> products = new ArrayList<>();

    products.add(new Product("Black Grapes", "480", "", "1", "0"));
    products.add(new Product("Oranges", "198", "", "1", "0"));
    products.add(new Product("Pears", "170", "", "1", "0"));
    products.add(new Product("Apple", "169", "", "1", "0"));
    products.add(new Product("Jonagold", "110", "", "1", "0"));
    products.add(new Product("Lemon", "198", "", "1", "0"));

    binding.rvProductList.setLayoutManager(new GridLayoutManager(this, 5));
    binding.rvProductList.setAdapter(new ProductsListAdapter(products, this));
}

@Override
public void onProductItemClicked(Product product) {

    myCurrentProduct = product;

    binding.setPopUpProduct(myCurrentProduct);
    binding.cvCurrentProduct.setVisibility(View.VISIBLE);

    binding.cvCurrentProduct.setOnClickListener(v -> {
        myCurrentProduct.setDiscount("100");
        myCurrentProduct.setPrice("50000");
        myCurrentProduct.setQuantity("5");
        myCurrentProduct.setTitle("Null");
        binding.setPopUpProduct(myCurrentProduct);
    });
}
}

ProductsListAdapter.java

public class ProductsListAdapter extends RecyclerView.Adapter<ProductsListAdapter.ViewHolder> {

private ProductItemClickListener mListener;
private List<Product> products;

public ProductsListAdapter(List<Product> products, ProductItemClickListener mListener) {
    this.products = products;
    this.mListener = mListener;
}

@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
    ItemListProductsBinding binding = DataBindingUtil.inflate(LayoutInflater.from(viewGroup.getContext()), R.layout.item_list_products, viewGroup, false);
    return new ViewHolder(binding);
}

@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int i) {

    holder.bind(products.get(i), mListener);

}

@Override
public int getItemCount() {
    return products.size();
}

class ViewHolder extends RecyclerView.ViewHolder {

    ItemListProductsBinding binding;

    public ViewHolder(ItemListProductsBinding binding) {
        super(binding.getRoot());
        this.binding = binding;

    }

    void bind(Product currentProduct, ProductItemClickListener clickListener){
        //For each item, corresponding product object is passed to the binding
        binding.setProduct(currentProduct);
        binding.setProductItemClick(clickListener);
        //This is to force bindings to execute right away
        binding.executePendingBindings();
    }
}

public interface ProductItemClickListener {
    void onProductItemClicked(Product product);
}
}

activity_main_testing.xml

<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">

<data>

    <variable
        name="popUpProduct"
        type="tech.oratier.parlour.models.Product" />


</data>


<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="2"
        android:orientation="vertical">

        <com.google.android.material.card.MaterialCardView
            android:id="@+id/cvCurrentProduct"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="8dp"
            android:layout_marginLeft="8dp"
            android:layout_marginEnd="8dp"
            android:layout_marginRight="8dp"
            android:layout_marginBottom="8dp"
            app:cardCornerRadius="5dp"
            app:cardElevation="5dp">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:paddingTop="8dp"
                android:paddingBottom="8dp">

                <LinearLayout
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:gravity="center">

                    <ImageView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:src="@mipmap/ic_launcher_round" />

                </LinearLayout>

                <LinearLayout
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="2"
                    android:orientation="vertical">

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:fontFamily="@font/garamond"
                        android:hint="Product Title"
                        android:text="@{popUpProduct.title}"
                        android:textSize="30sp"
                        android:textStyle="bold" />

                    <LinearLayout
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:orientation="horizontal">

                        <TextView
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:text="Quantity:"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                        <TextView
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:gravity="end"
                            android:text="@{popUpProduct.quantity}"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                    </LinearLayout>

                    <LinearLayout
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:orientation="horizontal">

                        <TextView
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:text="Discount:"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                        <TextView
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:gravity="end"
                            android:text="@{popUpProduct.discount}"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                    </LinearLayout>

                    <LinearLayout
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:orientation="horizontal">

                        <TextView
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:text="Price:"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                        <TextView
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:gravity="end"
                            android:text="@{popUpProduct.price}"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                    </LinearLayout>

                    <View
                        android:layout_width="match_parent"
                        android:layout_height="1dp"
                        android:background="@color/seperator" />

                    <LinearLayout
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:orientation="horizontal">

                        <TextView
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:text="Total"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                        <TextView
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:fontFamily="@font/garamond"
                            android:gravity="end"
                            android:text="@{popUpProduct.price != null ? (popUpProduct.quantity != null ? (popUpProduct.discount != null ? String.valueOf((Double.parseDouble(popUpProduct.price) * Double.parseDouble(popUpProduct.quantity)) - Double.parseDouble(popUpProduct.discount)) : String.valueOf(Double.parseDouble(popUpProduct.price) * Double.parseDouble(popUpProduct.quantity))) : @string/nothing) : @string/nothing}"
                            android:textSize="20sp"
                            android:textStyle="bold" />

                    </LinearLayout>
                </LinearLayout>

            </LinearLayout>
        </com.google.android.material.card.MaterialCardView>
    </LinearLayout>

    <View
        android:layout_width="3dp"
        android:layout_height="match_parent"
        android:background="@color/seperator" />

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="3"
        android:orientation="vertical">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/rvProductList"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="center" />
    </LinearLayout>
</LinearLayout>

item_list_products.xml

<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">

<data>
    <variable
        name="product"
        type="tech.oratier.parlour.models.Product" />

    <variable
        name="productItemClick"
        type="tech.oratier.parlour.adapters.ProductsListAdapter.ProductItemClickListener" />
</data>

<com.google.android.material.card.MaterialCardView
android:layout_marginTop="5dp"
android:layout_marginLeft="8dp"
android:layout_marginStart="8dp"
android:onClick="@{()->productItemClick.onProductItemClicked(product)}"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:contentPaddingRight="5dp"
android:orientation="vertical">

<LinearLayout
    android:paddingStart="16dp"
    android:paddingRight="16dp"
    android:paddingEnd="16dp"
    android:paddingLeft="16dp"
    android:paddingTop="8dp"
    android:paddingBottom="8dp"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

<RelativeLayout
    android:layout_width="100dp"
    android:layout_height="wrap_content">

    <ImageView
        android:layout_marginTop="8dp"
        android:src="@mipmap/ic_launcher_round"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

    <TextView
        android:fontFamily="@font/garabd"
        android:paddingLeft="8dp"
        android:paddingStart="8dp"
        android:paddingEnd="8dp"
        android:paddingRight="8dp"
        android:background="@color/priceBackground"
        android:textColor="@color/defaultTextColor"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:text="@{product.price}"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</RelativeLayout>

<com.google.android.material.textview.MaterialTextView
    android:singleLine="true"
    android:textSize="20sp"
    android:textColor="@android:color/black"
    android:fontFamily="@font/raleway_regular"
    android:layout_marginTop="8dp"
    android:layout_gravity="center_horizontal"
    android:text="@{product.title}"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

<com.google.android.material.textview.MaterialTextView
    android:singleLine="true"
    android:textSize="20sp"
    android:textColor="@android:color/black"
    android:fontFamily="@font/raleway_regular"
    android:layout_marginTop="8dp"
    android:layout_gravity="center_horizontal"
    android:text="@{product.quantity}"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

</LinearLayout>

Its working fine

Its working fine

Its working fine

Here I'm facing the problem

java android-studio android-recyclerview data-binding android-databinding
1个回答
0
投票

问题是我正在使用

myCurrentProduct = product;

此处将myCurrentProduct与product / layout绑定在一起，因此其值会自动更新。因此，为了摆脱这一点，我声明了另一个对象tempProduct as，

tempProduct = product;

然后我从tempProduct]获取值

myCurrentProduct = new Product();  //create a default constructor in Product model class
myCurrentProduct.setTitle(tempProduct.getTitle());
myCurrentProduct.setQuantity("5");
myCurrentProduct.setPrice("50000");
myCurrentProduct.setDiscount(tempProduct.getDiscount());
binding.setPopUpProduct(myCurrentProduct);

这样，我还可以从单击的项目中获取值，也可以设置自己的值。
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