Android的BaseAdapter：位置不是真正的位置？

Question

我很困惑，当使用BaseAdapter我的列表视图熄灭屏幕，每行不再保持连续的位置。我不知道该怎么比这个解释等。

如果我的BA / LV显示4项的屏幕上，并且予添加显示每行的一个TextView的视图，它显示为0,1,2,3行号（这是正确的）。但只要我滚动列表下到谷底4个项目（项目5-8），那么就说明那些作为4,5,0,1 ??为什么？？我很困惑：/我已尝试做各种各样的东西（甚至一些非常规的事情，但这是最后的事情我不工作）。

**编辑** 我发现，如果我改变

rv = (RowView) convertView;

到

rv =  new RowView(mContext,(cursor.getString(2)),
                        (cursor.getString(5)),
                        cursor.getString(cursor.getColumnIndex(DBHelper.KEY_IMAGEFILENAME)),
                        cursor.getString(cursor.getColumnIndex(DBHelper.KEY_CITY)),position);

，它的工作原理，但然后不重新使用的代码。所以我想我在正确的轨道上。我曾尝试一些方便的方法，但是这并没有帮助我太多，因为我需要之前构造发射了设置这些值。我是否需要创建一个新的方法和消防，在结束了吗？如addRow方法？这也导致它滚动很慢。

          @Override
               public void onCreate(Bundle bundle)
               {
                 super.onCreate(bundle);
                 //setContentView(R.layout.findlist);
                 //getListView().setEmptyView(findViewById(R.id.empty));
                 mDbHelper = new DBHelper(this);
                 mDbHelper.open();
                 cursor = mDbHelper.fetchAllLocations();
                 startManagingCursor(cursor);
                 mAdapter = new myListAdapter(this);
                 setListAdapter(mAdapter);

               }
    public class myListAdapter extends BaseAdapter {
            public String testing;
            public myListAdapter(Context c) {
                mContext = c;
                // TODO Auto-generated constructor stub
            }

            @Override
            public int getCount() {
                // TODO Auto-generated method stub
                return cursor.getCount();
            }

            @Override
            public Object getItem(int position) {
                // TODO Auto-generated method stub
                return position;
            }

            @Override
            public long getItemId(int position) {
                // TODO Auto-generated method stub
                return position;
            }

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {


                 cursor.moveToPosition(position);
                 RowView rv;


                 if (convertView == null) {
                        rv = new RowView(mContext,(cursor.getString(2)),
                                (cursor.getString(5)),
                                cursor.getString(cursor.getColumnIndex(DBHelper.KEY_IMAGEFILENAME)),
                                cursor.getString(cursor.getColumnIndex(DBHelper.KEY_CITY)),position);
                    } else {
                        rv = (RowView) convertView;
                        try {
              // I KNOW THIS SECTION IS NOT RIGHT, BUT I HAVE BEEN MESSING IN HERE          
                        rv.setAddress(cursor.getString(2));
                        rv.setCity(cursor.getString(5));
                        rv.setFocusable(true);
                        rv.setClickable(true); }
                        catch (Exception e) {
                            rv = (RowView) convertView;
                            rv.setAddress(cursor.getString(2));
                            rv.setCity(cursor.getString(5));
                            rv.setFocusable(true);
                            rv.setClickable(true); 
                            Toast mToast;
                            mToast = Toast.makeText(FindList.this, "Error :" + e.toString() ,
                                    Toast.LENGTH_LONG);
                            mToast.show();
                        }
                    }

                 return rv;
            }

            public void addItems() {

                 //String[] from = new String[] { DBHelper.KEY_BUSINESSNAME, DBHelper.KEY_ADDRESS, DBHelper.KEY_CITY, DBHelper.KEY_GPSLONG, DBHelper.KEY_GPSLAT,  DBHelper.KEY_IMAGEFILENAME  + ""};
                 // create array of values of widgits
                 //to = new int[] { R.id.businessname, R.id.address, R.id.city, R.id.gpslong, R.id.gpslat, R.id.preview};
                 // Now create an array adapter and set it to display using our row from notes_row.xml


            }



        }


private class RowView extends LinearLayout {
        private TextView mAddress;
        private TextView mCity;
        public ImageView mArrow;
        public ImageView mPicture;
        public String mPathName;
        public String mDateTime;
        public RowView(Context context, String title, String words, String pathName, String city, int position) {
            super(context);

            this.setOrientation(HORIZONTAL);
            this.setVerticalGravity(16); //CENTER_VERTICAL 

            // Here we build the child views in code. They could also have
            // been specified in an XML file.

            //DISPLAY DELETE BUTTON
            Button mButton = new Button(context);
            mButton.setFocusable(false);
            mButton.setId(position);
            mButton.setBackgroundResource(R.drawable.delete3);
            addView(mButton, new LinearLayout.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

            TextView mTitle;
            mTitle = new TextView(context);
            mTitle.setText(Integer.toString(position));
            addView(mTitle, new LinearLayout.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

            this.setOrientation(HORIZONTAL);      

            try {
             Bitmap bm = Bitmap.createScaledBitmap(BitmapFactory.decodeFile(cursor.getString(cursor.getColumnIndex(DBHelper.KEY_IMAGEFILENAME))),100, 100, true);
                mPicture = new ImageView(context);
                mPicture.setImageBitmap(bm);    
           } catch (Exception e) { 
                 mPicture = new ImageView(context);
                 mPicture.setImageResource(R.drawable.noimage);
           }     

            addView(mPicture, new LinearLayout.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

            mArrow = new ImageView(context);
            mArrow.setBackgroundResource(R.drawable.arrowleft3);
            addView(mArrow, new LinearLayout.LayoutParams(
                    LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

            currentPosition = position;
            Button button = (Button)findViewById(position);
            button.setOnClickListener(mCorkyListener);

        }

Answer 1

当使用convertView，则给出先前已经使用，但其不再被显示的视图。你应该采取与当前项目的价值重置的所有属性的照顾。否则，您必须在RowView构造函数设置的所有值将保持与你给这个视图创建它的第一次的值。

要更好地了解列表视图，你必须明白，它仅使用一组有限RowViews的，刚才那是足以填满显示器和数字多了一些，这将仅仅有显示在他们面前充满你的数据。