出现错误尝试在空对象引用上调用虚拟方法“void android.widget.TextView.setText(java.lang.CharSequence)”

Question

我正在尝试在 android 中设置回收器视图，但适配器类给了我错误，如标题中所述。我搜索并找到了this。这里的答案说命名不匹配。我检查了我的名字，但仍然收到错误消息。

这是适配器：

public class RecyclerViewAdapter3 extends RecyclerView.Adapter<RecyclerViewAdapter3.ViewHolder> {

Context context3;
List<ImageUploadInfo> MainImageUploadInfoList;


public RecyclerViewAdapter3(Context context, List<ImageUploadInfo> TempList) {

    this.MainImageUploadInfoList = TempList;

    this.context3 = context;
}

public RecyclerViewAdapter3.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false);

    ViewHolder viewHolder = new ViewHolder(view);

    return viewHolder;
}

@Override
public int getItemCount() {

    return MainImageUploadInfoList.size();
}

@Override
public void onBindViewHolder(final RecyclerViewAdapter3.ViewHolder holder, int position) {
    ImageUploadInfo UploadInfo = MainImageUploadInfoList.get(position);

    holder.imageNameTextView.setText(UploadInfo.getImageName());

    Uri uri = Uri.parse(UploadInfo.getImageURL());
    Log.d("TAGGG" , ""+uri);
    holder.userText.setText(uri.toString());
}

class ViewHolder extends RecyclerView.ViewHolder {
    public TextView imageNameTextView ;
    public TextView userText;


    public ViewHolder(View itemView) {
        super(itemView);

        userText = (TextView) itemView.findViewById(R.id.textView13);

        imageNameTextView = (TextView) itemView.findViewById(R.id.caption);
    }
}
}

这里是回收者将膨胀的 xml 文件（items3）：

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content">

<android.support.v7.widget.CardView
    android:layout_width="303dp"
    android:layout_height="378dp"
    android:layout_marginBottom="8dp"
    app:cardElevation="20dp"
    app:cardCornerRadius="20dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.0">

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

        <TextView
            android:id="@+id/textView13"
            android:layout_width="match_parent"
            android:layout_height="327dp"
            android:text="TextView" />

        <TextView
            android:id="@+id/caption"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:fontFamily="@font/aguafina_script"
            android:gravity="center"
            android:hint="Caption"
            android:textColor="@color/common_google_signin_btn_text_dark_focused"
            android:textSize="26sp" />
    </LinearLayout>
</android.support.v7.widget.CardView>

这是日志：

Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
    at com.avalonglobalresearch.creatives.RecyclerViewAdapter3.onBindViewHolder(RecyclerViewAdapter3.java:50)
    at com.avalonglobalresearch.creatives.RecyclerViewAdapter3.onBindViewHolder(RecyclerViewAdapter3.java:14)

图片上传信息：

public class ImageUploadInfo {

    public String imageName;

    public String imageURL;

    public ImageUploadInfo() {

    }

    public ImageUploadInfo(String name, String url) {

        this.imageName = name;
        this.imageURL= url;
    }

    public String getImageName() {
        return imageName;
    }

    public String getImageURL() {
        return imageURL;
    }
    }

请告诉我哪里出错了。

Answer 1

好的，所以我发现了问题，我膨胀了错误的 xml 文件。 View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false); 在这里，我没有膨胀 items3.xml ，而是膨胀了 recyclerview_items ，因此我得到了错误。

感谢大家帮助我，很抱歉浪费了大家的时间

Answer 2

使用这个：

holder.userText.setText(uri.toString()+"");

这可以处理任何数据类型的值

Answer 3

在您的onBindViewHolder 中尝试将持有者转换为ViewHolder

@Override
public void onBindViewHolder(final RecyclerViewAdapter3.ViewHolder holder, int position) {

    ViewHolder holderView = (ViewHolder)holder; // <-- Cast the ViewHolder

    ImageUploadInfo UploadInfo = MainImageUploadInfoList.get(position);

    holderView.imageNameTextView.setText(UploadInfo.getImageName());  // <-- use holderView instead of holder

    Uri uri = Uri.parse(UploadInfo.getImageURL());
    Log.d("TAGGG" , ""+uri);
    holderView.userText.setText(uri.toString());   // <-- use holderView instead of holder
}

Answer 4

public class RecyclerViewAdapter3 extends RecyclerView.Adapter<RecyclerViewAdapter3.ViewHolder> {

Context context3;
List<ImageUploadInfo> MainImageUploadInfoList;


public RecyclerViewAdapter3(Context context, List<ImageUploadInfo> TempList) {

this.MainImageUploadInfoList = TempList;

this.context3 = context;
}

public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false);

ViewHolder viewHolder = new ViewHolder(view);

return viewHolder;
}

@Override
public int getItemCount() {

return MainImageUploadInfoList.size();
 }

@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
ImageUploadInfo UploadInfo = MainImageUploadInfoList.get(position);

holder.imageNameTextView.setText(UploadInfo.getImageName());

Uri uri = Uri.parse(UploadInfo.getImageURL());
Log.d("TAGGG" , ""+uri);
holder.userText.setText(""+uri.toString());
}

class ViewHolder extends RecyclerView.ViewHolder {
public TextView imageNameTextView ;
public TextView userText;


public ViewHolder(View itemView) {
    super(itemView);

    userText = (TextView) itemView.findViewById(R.id.textView13);

    imageNameTextView = (TextView) itemView.findViewById(R.id.caption);
   }
}

也检查 xml 文件名