Android：在 Recycler 视图中调用 Intent 时应用程序崩溃

Question

我创建了一个回收器视图，它在列表视图中显示来自 Sqlite 的图像和文本，为了将选定的项目名称传递给新的 Activity 我使用 Intent 传递数据，但是当我的 Intent 被调用时，我的应用程序是崩溃并显示 Attempt to invoke virtual method 'void android.content.Context.startActivity(android.content.Intent)' on a null object reference

回收者视图

ArrayList<byte[]> list_image;
private LayoutInflater mInflater;
private Context context;
private ArrayList<String> list_name;

 public void onBindViewHolder(@NonNull MyViewHolder holder, final int position) {

        holder.listname.setText(String.valueOf(list_name.get(position)));

       
        Bitmap bmp = BitmapFactory.decodeByteArray(list_image.get(position), 0, list_image.get(position).length);
        ImageView image = holder.imgname;
        
        image.setImageBitmap(bmp);
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Intent intent = new Intent(view.getContext(),AddItems.class);
                intent.putExtra("listname", String.valueOf(list_name.get(position)));
                context.startActivity(intent);

            }
        });
    }

添加项目

  lisname = findViewById(R.id.listname_dis);

        Intent intent = getIntent();
        String dataTransmited=intent.getStringExtra("listname");
        lisname.setText(dataTransmited);
    }

logcat :

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.content.Context.startActivity(android.content.Intent)' on a null object reference
        at com.Karthi.check.CustomAdapter.onClick(CustomAdapter.java:76)

Answer 1

因为您的“上下文”为空试试这个：

view.getContext().startActivity(intent)

而不是这个：

context.startActivity(intent)

Answer 2

在您的自定义适配器中初始化 private Activity activity;

然后

public CustomAdapter(Activity activity,....){

 this.activity = activity;
......
.....
....
}


   use  activity.startActivity(intent); in your OnClickListerner


holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Intent intent = new Intent(view.getContext(),AddItems.class);
                intent.putExtra("listname", String.valueOf(list_name.get(position)));
                activity.startActivity(intent);

            }

也在你的主activity添加

CustomAdapter ca = new CustomAdapter(MainActivity.this,this,......)

Android：在 Recycler 视图中调用 Intent 时应用程序崩溃

Android : App Crashed When Intent called inside the Recycler View

android

android-intent

android-recyclerview