如何覆盖 ArrayAdapter add 方法以向其添加图像和文本视图？ 我有自定义数组适配器类

Question

I am successfully adding image with text when I initialize adapter object and set it as listview adapter but I want to add more items to it when I get more data from internet which includes image. I am retrieving information from internet using json which includes image url. Here is my adapter code

public class CustomList extends ArrayAdapter<String>{

    private final Activity context;
    private final String[] web;
    private final Integer[] imageId;
    public CustomList(Activity context,
                      String[] web, Integer[] imageId) {
        super(context, R.layout.list_single, web);
        this.context = context;
        this.web = web;
        this.imageId = imageId;

    }

    @Override
    public View getView(int position, View view, ViewGroup parent) {
        LayoutInflater inflater = context.getLayoutInflater();
        View rowView= inflater.inflate(R.layout.list_single, null, true);
        TextView txtTitle = (TextView) rowView.findViewById(R.id.txt);

        ImageView imageView = (ImageView) rowView.findViewById(R.id.img);
        txtTitle.setText(web[position]);

        imageView.setImageResource(imageId[position]);
        return rowView;
    }
}

I want to add more items to it after I have set the array adapter.(images with text) I know how to add text only.

Answer 1

First of all, I would suggest to use an ArrayList for the String and Integer objects, instead of normal arrays. With this you can more easily append data.

In your Activity , you keep the reference to the String and Integer ArrayList objects you pass to the Adapter. When you receive new date, you simply add this data to the lists.

When the data is updated, you should call the notifyDataSetChanged() method of the adapter to display the data in your view.

--EDIT--

Another suggestion: you should recycle the views already created in the getView method. You can do this by checking if the provided contentview (the second argument) is null. This will greatly improve the performance of larger ListViews

    public View getView(int position, View view, ViewGroup parent) {
        if(view == null){
            LayoutInflater inflater = context.getLayoutInflater();
            view= inflater.inflate(R.layout.list_single, null, true);
         }
            TextView txtTitle = (TextView) view.findViewById(R.id.txt);

            ImageView imageView = (ImageView) view.findViewById(R.id.img);
            txtTitle.setText(web[position]);

            imageView.setImageResource(imageId[position]);
            return view;
        }

Answer 2

Try this at the beginning of your getView method:

LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView= inflater.inflate(R.layout.list_single, null); //Try both with ", true" and without. 

Also, try to build and pass a Drawable object to imageView.setImageResource(....);