Question

我已经制作了自定义ListView，我希望能够点击一个小按钮或整行。所以我为2个案件制作了2个单独的onclicklisteners。我如何参考按钮？它给了我这个错误：

Cannot refer to a non-final variable viewHolder inside an inner class defined in a different method

我不能让它成为最终版，因为它会不断变化。这是我的代码。

    public class ListViewAdapter extends ArrayAdapter<String> {

        private static LayoutInflater inflater = null;

        public Context context; 
        public int layoutResourceId;
        public ArrayList<HashMap<String, Object>> items;
        public Bitmap icon;
        private static int REFRESH_THRESHOLD = 2;

        //public ImageLoader imageLoader;

        public ListViewAdapter(Context context, int listviewItemRow, ArrayList<HashMap<String, Object>> items, Bitmap icon) {
            // TODO Auto-generated constructor stub
            super(context, listviewItemRow);
            this.items = items;
            this.context = context;
            this.icon = icon;
        }

        public int getCount() {
            return items.size();
        }

        public Item getItem(Item position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(final int position, View convertView, ViewGroup parent) {
            View row = convertView;
            ViewHolder viewHolder = new ViewHolder();

            if (row == null) {

                inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                row = inflater.inflate(R.layout.listview_item_row, null);       

                viewHolder.ic_thumbnail = (ImageView)row.findViewById(R.id.ic_thumbnail);
                viewHolder.scadenza = (TextView)row.findViewById(R.id.tvScadenza);
                viewHolder.prezzo = (TextView)row.findViewById(R.id.tvPrezzo);
                viewHolder.followers = (TextView)row.findViewById(R.id.tvFollowers);
                viewHolder.hProgressBar = (ProgressBar)row.findViewById(R.id.hProgressBar);
                viewHolder.followButton = (Button) row.findViewById(R.id.btnFollow);

                row.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder)row.getTag();
            }

            HashMap<String, Object> item = items.get(position);
            viewHolder.ic_thumbnail.setImageBitmap((Bitmap) item.get("pic1m"));
            viewHolder.scadenza.setText((CharSequence) item.get("scadenza"));
            viewHolder.prezzo.setText((CharSequence) item.get("prezzo"));
            viewHolder.followers.setText((CharSequence) item.get("followers"));
            viewHolder.hProgressBar.setProgress((Integer) item.get("coefficient"));
            viewHolder.followButton.setText("non segui");
            viewHolder.followButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
//here i get the error
                    viewHolder.followButton = (Button) row.findViewById(R.drawable.action_object_button_gray);
                    followButton.setText("segui");
                }
            });


            row.setOnClickListener(new OnItemClickListener(position));


            return row;
        }

        private class OnItemClickListener implements OnClickListener {

            private int mPosition;

            private OnItemClickListener(int position){
                mPosition = position;
            }

            @Override
            public void onClick(View v) {

                Log.i("onListItemClickList", "Item clicked: " + mPosition);
                Toast.makeText(context, "Message " + Integer.toString(mPosition), Toast.LENGTH_SHORT).show();

                Intent intent = new Intent(context, DettagliActivity.class);
                Bundle bundle = new Bundle();
                bundle.putInt("id", mPosition);
                intent.putExtras(bundle);
                context.startActivity(intent);
            }   
        }

        public static class ViewHolder {
            public TextView prezzo;
            public TextView scadenza;
            public TextView followers;
            public ImageView ic_thumbnail;
            public ProgressBar hProgressBar;
            public Button followButton;
        }
    }

Answer 1

而不是这个

viewHolder.followButton = (Button) row.findViewById(R.drawable.action_object_button_gray);
followButton.setText("segui");

您可以使用

Buttom button =(Button)v; // casting view to button
button.setText("segui");  // set text to button

如果在匿名内部类中使用变量，则要求变量为final。

参考

http://docs.oracle.com/javase/tutorial/java/javaOO/anonymousclasses.html#accessing

Why are only final variables accessible in anonymous class?

Answer 2

由于您正在对您感兴趣的按钮设置onClickListener，为什么不将视图转换为按钮并使用view参数对其进行修改？

viewHolder.followButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
//here i get the error
                    Button view = (Button) v;
                    view.setText("segui");
                }
            });

Answer 3

简单的解决方案是

final ViewHolder temp = viewHolder;

并使用它。

修改自定义listView中的按钮

3 个答案: