Java 在RecyclerView'；中将文本设置为EditText时出错；s onBindViewHolder方法
我试图在自定义适配器内将文本设置为Java 在RecyclerView'；中将文本设置为EditText时出错；s onBindViewHolder方法,java,android,android-recyclerview,android-arrayadapter,Java,Android,Android Recyclerview,Android Arrayadapter,我试图在自定义适配器内将文本设置为EditText，我得到以下堆栈： 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.
EditTextjava.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.
TextViewViewHolderpublic 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();
}
}
查看绑定后，应调用TextWatch上的侦听器集。在
onBindViewHolder......
@Override
public void onBindViewHolder(@NonNull ProductListViewHolder productListViewHolder, final int position) {
......
productListViewHolder.productChangeListener();
....
我还建议更改注册侦听器的函数。在
RecyclerViewTextWatcherproductItemManager.setProductQuantity（）productQuantityview.OnFocusChangeListener（）。换句话说，文本观察程序仅在编辑EditText
时才处于活动状态
productQuantity.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (hasFocus) {
productQuantity.addTextChangedListener(textWatcher);
} else {
productQuantity.removeTextChangedListener(textWatcher);
}
}
});
这可能无法解决您的问题，但它将消除可能是促成因素的不必要工作
我认为发布setProductQuantity（）
将有助于找到问题的根源。我同意@Cheticamp提出的实施方案。根据我的经验，文本更改侦听器可能会在不应该调用它的不同情况下触发。EditText
通常用于自动更正单词和提供建议，并可在初始化过程中调用。因此，我建议您在布局文件的EditText
声明中添加以下内容
android:inputType="textNoSuggestions"
而不是使用<代码> StEnFoCuxCuxelister-< /C> >您可以考虑使用<代码> null >代码>检查您的文本监视器，如下所示。p>
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) {
String editTextContent = productQuantity.getText().toString();
if(editTextContent != null && editTextContent.trim().length() > 0) {
Double quantity = Double.parseDouble(productQuantity.getText().toString());
productItemManager.setProductQuantity(getAdapterPosition(), quantity);
}
}
@Override
public void afterTextChanged(Editable s) {
}
});
}
希望有帮助 有几件事需要你注意：
在RecyclerViews（以及通常的列表）中使用EditText通常不是一个好主意，因为它们的用户体验（UX）。您必须阻止用户滚动列表，或者根据滚动执行一些操作，以使事情更顺利（因为他们可能正在输入某些内容）
代码中有一个非常重要的问题，那就是引用正在回收的编辑文本的“TextWatcher”。在回收视图时，需要删除文本监视程序。如果不删除TextWatcher，会发生什么？由于它不同于OnClickListener
（它不是set
函数，而是add
函数），因此每次重新创建单元格时，都会向EditText添加一个新的文本观察程序，并将其引用到旧的ViewHolder
要解决此问题，您需要向ViewHolder添加一个方法，以解除其持有的任何内容的绑定：
public class ProductListViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView productDescription, productSellingPrice, productFinalPrice;
public ImageView removeProductIcon;
public EditText productQuantity;
private ProductItemManager productItemManager;
private TextWatcher textWatcher;
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() {
textWatcher = 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) {
}
};
productQuantity.addTextChangedListener(textWatcher);
}
public void unbind(){
productQuantity.removeTextChangedListener(textWatcher);
}
@Override
public void onClick(View v) {
productItemManager.removeProduct(getAdapterPosition());
}
}
然后，您可以使用RecyclerView的onViewRecyclered
方法来了解视图何时被回收，并删除TextWatcher：
@Override
public void onViewRecycled(ProductListViewHolder productListViewHolder) {
super.onViewRecycled(holder);
productListViewHolder.unbind();
}
可能重复完整堆栈跟踪后不仅错误我编辑了添加完整堆栈的问题。因此我刚刚测试了应用程序，发现问题似乎只有在ProductListViewHolder的构造函数中有TextWatcher侦听器时才会出现。如果您能想到这一点，我将不胜感激。如果您发布ProductItemManager类代码，那将非常有帮助，因为这就是这个bug的来源。根据我读到的一篇文章，在视图持有者之外声明侦听器是一种不好的做法。这是真的吗？作者建议在viewholder上实现监听器，然后创建一个我自己的接口，该接口将由我的活动扩展，在那里我的接口的方法应该被覆盖。这就是我在点击事件中对ViewHolder所做的，效果很好。你能进一步解释一下吗？原来的线路出了什么问题，你做了什么使它工作？请记住，OP应该能够从您的改进中学习，而不是简单地复制它。最近我遇到了同样的问题，我通过直接访问主列表位置解决了它。请将所有解释添加到答案中，而不是添加到评论部分。此外，请更深入地解释您所做的更改及其原因-原始代码有什么问题？
@Override
public void onViewRecycled(ProductListViewHolder productListViewHolder) {
super.onViewRecycled(holder);
productListViewHolder.unbind();
}
//update this line in your code, you will get your answer :)
productListViewHolder.productQuantity.setText(Double.toString(productList.get(position).getQuantity()));