Java 运行项目时出现NullPointerException
我的代码有问题,这是错误 java.lang.NullPointerException:尝试调用虚拟方法 空对象上的“void android.widget.ImageView.setImageResource(int)”无效 参考文献 代码中并没有错误,但当运行时有一个null异常错误,我不知道哪里是null,这是错误 在 com.mulazi.submission2.MovieListAdapter.onBindViewHolder(MovieListAdapter.java:57) 在com.mulazi.submission2.MovieListAdapter.onBindViewHolder(MovieListAdapter.java:20)上 这是我的密码Java 运行项目时出现NullPointerException,java,android,nullpointerexception,argumentnullexception,Java,Android,Nullpointerexception,Argumentnullexception,我的代码有问题,这是错误 java.lang.NullPointerException:尝试调用虚拟方法 空对象上的“void android.widget.ImageView.setImageResource(int)”无效 参考文献 代码中并没有错误,但当运行时有一个null异常错误,我不知道哪里是null,这是错误 在 com.mulazi.submission2.MovieListAdapter.onBindViewHolder(MovieListAdapter.java:57) 在co
package com.mulazi.submission2;
import android.content.Intent;
import android.provider.ContactsContract;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.mulazi.submission2.R;
import com.mulazi.submission2.DetailActivity;
import com.mulazi.submission2.Movie;
import java.util.ArrayList;
import java.util.List;
public class MovieListAdapter extends RecyclerView.Adapter<MovieListAdapter.MovieViewHolder> {
private List<Movie> movieList;
public MovieListAdapter() {
movieList = new ArrayList<>();
}
private void add(Movie item) {
movieList.add(item);
notifyItemInserted(movieList.size() - 1);
}
public void addAll(List<Movie> movieList) {
for (Movie movie : movieList) {
add(movie);
}
}
@NonNull
@Override
public MovieViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_movie, parent, false);
return new MovieViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final MovieViewHolder holder,final int position) {
final Movie movie = movieList.get(position);
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(holder.itemView.getContext(), DetailActivity.class);
intent.putExtra("key", movie);
holder.itemView.getContext().startActivity(intent);
}
});
holder.moviePhoto.setImageResource(movie.getPhoto());
holder.movieName.setText(movie.getName());
holder.movieDate.setText(movie.getDate());
holder.movieDesc.setText(movie.getDescription());
holder.movieDuration.setText(movie.getDuration());
holder.movieDirector.setText(movie.getDirector());
holder.movieGenre.setText(movie.getGenre());
}
@Override
public int getItemCount() {
return movieList.size();
}
static class MovieViewHolder extends RecyclerView.ViewHolder {
ImageView moviePhoto;
TextView movieName;
TextView movieDesc;
TextView movieDate;
TextView movieDuration;
TextView movieDirector;
TextView movieGenre;
MovieViewHolder(@NonNull View itemView) {
super(itemView);
moviePhoto = itemView.findViewById(R.id.img_photo);
movieName = itemView.findViewById(R.id.txt_name);
movieDesc = itemView.findViewById(R.id.txt_description);
movieDate = itemView.findViewById(R.id.txt_date);
movieDirector = itemView.findViewById(R.id.txt_director);
movieDuration = itemView.findViewById(R.id.txt_duration);
movieGenre = itemView.findViewById(R.id.txt_genre);
}
}
}
package com.mulazi.submission2;
导入android.content.Intent;
导入android.provider.contacts合同;
导入android.support.annotation.NonNull;
导入android.support.v7.widget.RecyclerView;
导入android.view.LayoutInflater;
导入android.view.view;
导入android.view.ViewGroup;
导入android.widget.ImageView;
导入android.widget.TextView;
导入com.mulazi.submission2.R;
导入com.mulazi.submission2.DetailActivity;
导入com.mulazi.submission2.Movie;
导入java.util.ArrayList;
导入java.util.List;
公共类MovieListAdapter扩展了RecyclerView.Adapter{
私人名单电影演员;
公共MovieListAdapter(){
movieList=newarraylist();
}
私有无效添加(电影项目){
电影列表。添加(项目);
notifyItemInserted(movieList.size()-1);
}
公共void addAll(列表movieList){
为(电影:影迷){
添加(电影);
}
}
@非空
@凌驾
public MovieViewHolder onCreateViewHolder(@NonNull ViewGroup父级,int-viewType){
View View=LayoutInflater.from(parent.getContext()).flate(R.layout.list\u item\u movie,parent,false);
返回新的MoviewHolder(视图);
}
@凌驾
BindViewHolder上的公共无效(@NonNull final MovieViewHolder,final int位置){
最终电影=movieList.get(位置);
holder.itemView.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图){
Intent Intent=新的Intent(holder.itemView.getContext(),DetailActivity.class);
意图。putExtra(“钥匙”,电影);
holder.itemView.getContext().startActivity(intent);
}
});
holder.moviePhoto.setImageResource(movie.getPhoto());
holder.movieName.setText(movie.getName());
holder.movieDate.setText(movie.getDate());
holder.movieDesc.setText(movie.getDescription());
holder.movieDuration.setText(movie.getDuration());
holder.movieDirector.setText(movie.getDirector());
holder.movieGenre.setText(movie.getGenre());
}
@凌驾
public int getItemCount(){
返回movieList.size();
}
静态类MovieViewHolder扩展了RecyclerView.ViewHolder{
ImageView电影照片;
TextView movieName;
TextView movieDesc;
TextView电影日期;
TextView电影持续时间;
TextView电影导演;
文本视图电影类型;
MovieViewHolder(@NonNull View itemView){
超级(项目视图);
moviePhoto=itemView.findviewbyd(R.id.img_photo);
movieName=itemView.findviewbyd(R.id.txt\u名称);
movieDesc=itemView.findviewbyd(R.id.txt\u说明);
movieDate=itemView.findviewbyd(R.id.txt\u日期);
movieDirector=itemView.findviewbyd(R.id.txt\u director);
movieDuration=itemView.findviewbyd(R.id.txt\u duration);
movieGenre=itemView.findviewbyd(R.id.txt\u流派);
}
}
}
我希望有人能帮助我解决这个错误,检查您的布局文件。很可能您忘记在布局中放置img_照片:
moviePhoto = itemView.findViewById(R.id.img_photo);
错误出现在第57行holder.moviePhoto.setImageResource(movie.getPhoto())代码>。此外,错误表明您正在对null对象调用setImageResource(…),这表明holder.moviePhoto为null。@KevinBarron那么我应该怎么做?xml和id之间没有任何错误