由于尝试调用虚拟方法'java.lang.String android.content.Context.getPackageName()，意图失败 [英] Intent fails because of Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()

问题描述

我有什么:我有一个 RecyclerView，里面有酒吧、咖啡店的图片.等

What I have: I have a RecyclerView with images of bars, coffee shops. etc

我想要的是:当您单击这些图像之一时，我会向您显示所选地点的信息，但是在您单击所选图像的那一刻，应用程序崩溃并显示此错误尝试调用虚拟方法"java.lang.String android.content.Context.getPackageName()' on a null object reference" 在我创建 Intent 的那一行.我已经在寻找这个错误，但我正在做他们所说的一切

What I want: That when you click on one of these images I show you the info of the selected place, but on the moment that you click the selected image the app crashes and shows this error "Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference" on the line where i create the Intent. I have already looked for this error but i am doing everything as they say

我的问题:我该如何解决这个问题?拜托，我非常感谢代码示例，我还不擅长编程，在此先感谢

My question: How do I fix this? Please, I would really appreciate the examples with code, i am not good at programming yet, thanks in advance

我的java类

    public class foodAndGo extends AppCompatActivity {
    ArrayList<ClaseNueva> listalugares;
    RecyclerView recyclerview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_food_and_go);

       listalugares = new ArrayList<ClaseNueva>();
       recyclerview = (RecyclerView) findViewById(R.id.RecyclerID);
       recyclerview.setLayoutManager(new LinearLayoutManager(this));

       llenarLugares();

       AdapterDatos adapter = new AdapterDatos(foodAndGo.this, listalugares);
       recyclerview.setAdapter(adapter);

    }

    private void llenarLugares() {
        listalugares.add(new ClaseNueva("Restaurantes", R.drawable.carnemejor));
        listalugares.add(new ClaseNueva("Bares", R.drawable.beers));
        listalugares.add(new ClaseNueva("Cafeterías", R.drawable.desayunosmejor));
        listalugares.add(new ClaseNueva("Pizzerías", R.drawable.pizzaamejor));
        listalugares.add(new ClaseNueva("Favoritos", R.drawable.favoritosmejo));

    }
}

我的适配器

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


    ArrayList<ClaseNueva>listalugares;
    Context context;

    public AdapterDatos(foodAndGo foodAndGo, ArrayList<ClaseNueva> listalugares) {
        this.context = context;
        this.listalugares = listalugares;
    }


    static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {//quizas poner esto en estatic
        TextView etiNombre;
        ImageView foto;

//        Context context;

        public ViewHolder(View itemView) {
            super(itemView);
//            context = itemView.getContext();

            etiNombre = (TextView) itemView.findViewById(R.id.idNombre);
            foto = (ImageView) itemView.findViewById(R.id.idImagen);
        }
        void setOnClickListeners(){
            foto.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
//            switch (v.getId()){
//                case R.id.idImagen:
//                    Intent intent = new Intent(context, MapsActivity.class);
//                    context.startActivity(intent);
//                    break;
//            }

        }
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_list,null,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        holder.etiNombre.setText(listalugares.get(position).getNombre());
        holder.foto.setImageResource(listalugares.get(position).getFoto());

//        holder.setOnClickListeners();
       if (position == 0){
           holder.foto.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View v) {
                   Intent myIntent = new Intent(context, MapsActivity.class);
                   context.startActivity(myIntent);
               }
           });
       }
    }

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

}

推荐答案

我想你忘了从 Activity 传递上下文！

I think you forget to pass context from activity !

AdapterDatos adapter = new AdapterDatos(foodAndGo.this,listalugares);

在适配器中接收上下文:-

Receive context in Adapter :-

public AdapterDatos(Context context , ArrayList<ClaseNueva> listalugares) {
        this.context = context;
        this.listalugares = listalugares;
    }

希望对你有帮助！

这篇关于由于尝试调用虚拟方法'java.lang.String android.content.Context.getPackageName()，意图失败的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！