尝试在空对象引用上调用虚方法’int java.lang.String.length（）’
所以我有带有Tabs和RecyclerView Android应用程序。 当我运行我的应用程序时，它崩溃了。
logcat的：
java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference at java.io.StringReader.(StringReader.java:47) at android.text.HtmlToSpannedConverter.convert(Html.java:442) at android.text.Html.fromHtml(Html.java:136) at android.text.Html.fromHtml(Html.java:99) at com.example.app.MyRecyclerViewAdapter2.onBindViewHolder(MyRecyclerViewAdapter2.java:80) at com.example.app.MyRecyclerViewAdapter2.onBindViewHolder(MyRecyclerViewAdapter2.java:17) ...
在com.example.app.MyRecyclerViewAdapter2.onBindViewHolder（MyRecyclerViewAdapter2.java:80）
它指向代码的这一行
listRowViewHolder.postId.setText(Html.fromHtml(listItems.getPostId())); // This line of code leads to crashing of app
如果我删除此行，我的应用程序将正常工作。
MyRecyclerViewAdapter2.java：
package com.example.app; import android.content.Context; import android.content.Intent; import android.support.v7.widget.RecyclerView; import android.text.Html; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import com.android.volley.toolbox.ImageLoader; import java.util.List; public class MyRecyclerViewAdapter2 extends RecyclerView.Adapter { private List listItemsList; private Context mContext; private ImageLoader mImageLoader; private int focusedItem = 0; public MyRecyclerViewAdapter2(Context context, List listItemsList) { this.mContext = context; this.listItemsList = listItemsList; } @Override public ListRowViewHolder onCreateViewHolder(final ViewGroup viewGroup, int position) { View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_view_row2, null); ListRowViewHolder holder = new ListRowViewHolder(v); holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { TextView postUrl = (TextView) v.findViewById(R.id.postId); String post_Id = postUrl.getText().toString(); Intent intent = new Intent(mContext, ViewPostActivity.class); intent.putExtra("id", post_Id); mContext.startActivity(intent); } }); return holder; } @Override public void onBindViewHolder(ListRowViewHolder listRowViewHolder, int position) { ListItems listItems = listItemsList.get(position); listRowViewHolder.itemView.setSelected(focusedItem == position); listRowViewHolder.getLayoutPosition(); mImageLoader = MySingleton.getInstance(mContext).getImageLoader(); listRowViewHolder.thumbnail.setImageUrl(listItems.getThumbnail(), mImageLoader); listRowViewHolder.thumbnail.setDefaultImageResId(R.drawable.website_placeholder); listRowViewHolder.title.setText(Html.fromHtml(listItems.getTitle())); listRowViewHolder.date.setText(Html.fromHtml(listItems.getDate())); listRowViewHolder.content.setText(Html.fromHtml(listItems.getContent())); listRowViewHolder.postId.setText(Html.fromHtml(listItems.getPostId())); // This line of code leads to crashing of app } public void clearAdapter () { listItemsList.clear(); notifyDataSetChanged(); } @Override public int getItemCount() { return (null != listItemsList ? listItemsList.size() : 0); }}
您的错误，因为您在空字符串上调用Html.fromHtml 。 您应该在调用Html.fromHtml之前测试listItems.getPostId()的值。