android - 在 getView 方法中返回不正确的位置

Question

我正在使用扩展 BAseAdapter 的 CustomGridAdapter 以在 ListView 中显示数组的值。但在 CustomGridAdapter 的 getView 中，数组值的位置不在流中。

public class CustomGridAdapter extends BaseAdapter {

    private Context context; 
    private final String[] gridValues;
    private final String[] gridImage;

    //Constructor to initialize values
    public CustomGridAdapter(Context context, String[] gridValues, String[] gridImage) {
        this.context = context;
        this.gridValues = gridValues;
        this.gridImage=gridImage;
    }

    @Override
    public int getCount() {

        // Number of times getView method call depends upon gridValues.length
        return gridValues.length;
    }

    @Override
    public Object getItem(int position) {

        return gridValues[position];
    }

    @Override
    public long getItemId(int position) {

        return 0;
    }


    // Number of times getView method call depends upon gridValues.length

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

        //LayoutInflator to call external grid_item.xml file

        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View gridView;

        if (convertView == null) {

            gridView = new View(context);

            // get layout from grid_item.xml
            gridView = inflater.inflate(R.layout.grid_item, null);

            // set value into textview

            TextView textView = (TextView) gridView.findViewById(R.id.grid_item_label);
            textView.setText(gridValues[position]);
            Log.i(new Integer(position).toString(),gridValues[position] );
            ImageView grp_icon=(ImageView)gridView.findViewById(R.id.grid_item_image);
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inPreferredConfig = Bitmap.Config.ARGB_8888;
            String path="/sdcard/Letsmeet/letsmeet_media/group_images/"+gridImage[position];
            Bitmap bitmap = BitmapFactory.decodeFile(path, options);
            grp_icon.setImageBitmap(bitmap);
            // set image based on selected text

            ImageView imageView = (ImageView) gridView
                    .findViewById(R.id.grid_item_image);

            String mobile = gridValues[position];



        } else {
            gridView = (View) convertView;
        }

        return gridView;
    }
}

在 customGridAdapter 的 getView 方法中，位置顺序为 0,1,2,0,4 为什么我在 2 之后得到 0 而不是 3？

Answer 1

@Override
public long getItemId(int position) {

    return position; //return position here
}

让你的 getView 为，

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

    //LayoutInflator to call external grid_item.xml file

    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View gridView;

    if (convertView == null) {

        gridView = new View(context);

        // get layout from grid_item.xml
        gridView = inflater.inflate(R.layout.grid_item, null);

        // set value into textview

        TextView textView = (TextView) gridView.findViewById(R.id.grid_item_label);
        textView.setText(gridValues[position]);
        Log.i(new Integer(position).toString(),gridValues[position] );
        ImageView grp_icon=(ImageView)gridView.findViewById(R.id.grid_item_image);        



    } else {
        gridView = (View) convertView;
    }

        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inPreferredConfig = Bitmap.Config.ARGB_8888;
        String path="/sdcard/Letsmeet/letsmeet_media/group_images/"+gridImage[position];
        Bitmap bitmap = BitmapFactory.decodeFile(path, options);
        grp_icon.setImageBitmap(bitmap);
        // set image based on selected text

        ImageView imageView = (ImageView) gridView
                .findViewById(R.id.grid_item_image);

        String mobile = gridValues[position];

    return gridView;
}

您的 converView 仅对于屏幕上最初显示的 View 数为空。一旦你滚动它们 converView != null 并且它们被回收。所以把你的代码移到它外面。