java - 在 RecyclerView 的 onBindViewHolder 方法中将文本设置为 EditText 时出错

Question

我正在尝试将文本设置为我的自定义适配器中的 EditText，并且我得到了这个堆栈:

java.lang.NullPointerException: Attempt to read from field 'android.support.v7.widget.ViewInfoStore android.support.v7.widget.RecyclerView.mViewInfoStore' on a null object reference
    at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:8194)
    at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8180)
    at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8168)
    at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1573)
    at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1519)
    at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:614)
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3812)
    at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:3225)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
    at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
    at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
    at android.view.View.measure(View.java:17547)
    at android.widget.ScrollView.measureChildWithMargins(ScrollView.java:1260)
    at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
    at android.widget.ScrollView.onMeasure(ScrollView.java:337)
    at android.view.View.measure(View.java:17547)
    at android.support.constraint.ConstraintLayout.onMeasure(ConstraintLayout.java:1676)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
    at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
    at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:141)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
    at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:400)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
    at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
    at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
    at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
    at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
    at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
    at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2615)
    at android.view.View.measure(View.java:17547)
    at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2015)
    at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1173)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1379)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
    at android.view.Choreographer.doCallbacks(Choreographer.java:580)
    at android.view.Choreographer.doFrame(Choreographer.java:550)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5254)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)


at com.andro
02-21 14:14:29.702 1707-1707/com.android.inputmethod.latin E/RichInputConnection: Unable to connect to the editor to retrieve text.
02-21 14:14:31.705 1707-1707/com.android.inputmethod.latin E/RichInputConnection: Unable to connect to the editor to retrieve text.
02-21 14:14:33.706 1707-1707/com.android.inputmethod.latin E/RichInputConnection: Unable to connect to the editor to retrieve text.
02-21 14:14:35.709 1707-1707/com.android.inputmethod.latin E/RichInputConnection: Unable to connect to the editor to retrieve text.

我不确定哪里出了问题，我正在以完全相同的方式将文本设置为 TextView，并且工作正常。我查看了论坛和文章，我见过有类似问题的人，但似乎他们要么没有将 View 与我的 ViewHolder 属性正确绑定(bind)，要么试图访问

这是我的自定义适配器类:

public class ProductListAdapter extends RecyclerView.Adapter<ProductListViewHolder>{
    private List<Product> productList;
    private ProductItemManager productItemManager;

    public ProductListAdapter(List<Product> productList, ProductItemManager productItemManager) {
        this.productList = productList;
        this.productItemManager = productItemManager;
    }

    @NonNull
    @Override
    public ProductListViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View productListView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.adapter_product_list, parent, false);
        return new ProductListViewHolder(productListView, productItemManager);
    }

    @Override
    public void onBindViewHolder(@NonNull ProductListViewHolder productListViewHolder, final int position) {
        Product product = productList.get(position);

        Double finalPrice = product.getSellingPrice() * product.getQuantity();

        productListViewHolder.productDescription.setText(product.getDescription());
        productListViewHolder.productSellingPrice.setText("un. " + Utils.doubleToReal(product.getSellingPrice()));
        productListViewHolder.productFinalPrice.setText(Utils.doubleToReal(finalPrice));
        productListViewHolder.productQuantity.setText(Double.toString(product.getQuantity()));
    }

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

这是我的 ViewHolder

public class ProductListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    public TextView productDescription, productSellingPrice, productFinalPrice;
    public ImageView removeProductIcon;
    public EditText productQuantity;
    private ProductItemManager productItemManager;

    public ProductListViewHolder(View itemView, ProductItemManager productItemManager) {
        super(itemView);

        productDescription = itemView.findViewById(R.id.productDescription);
        productSellingPrice = itemView.findViewById(R.id.productSellingPrice);
        productFinalPrice = itemView.findViewById(R.id.productFinalPrice);
        removeProductIcon = itemView.findViewById(R.id.removeProductIcon);
        productQuantity = itemView.findViewById(R.id.productQuantity);

        this.productItemManager = productItemManager;

        removeProductIcon.setOnClickListener(this);

        this.productChangeListener();
    }

    private void productChangeListener() {
        productQuantity.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                Double quantity = Double.parseDouble(productQuantity.getText().toString());
                productItemManager.setProductQuantity(getAdapterPosition(), quantity);
            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });
    }

    @Override
    public void onClick(View v) {
        productItemManager.removeProduct(getAdapterPosition());
    }
}

Answer 1

您应该在查看绑定(bind)后调用 TextWatch 上设置的监听器。在onBindViewHolder调用你的注册。

......
@Override
public void onBindViewHolder(@NonNull ProductListViewHolder productListViewHolder, final int position) {
......
productListViewHolder.productChangeListener();
....

而且我还建议更改注册监听器的功能。在 RecyclerView 创建过程中，没有创建数百个项目。