使用 ArrayAdapter 在 Android 中创建列表

Question

我是这方面的新手，对事情如何运作的解释真的很有用。

所以我有这个class

        static class ListAdapter extends ArrayAdapter<String>{
            List<String> elements;
            Context context;

            public ListAdapter(Context context, List<String> elements) {
                super(context, 0, elements);
                this.context = context;
                this.elements = elements;
            }


            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                if (convertView == null) {
                    convertView = LayoutInflater.from(context).inflate(R.layout.list_item_ex, null, false);
                }

                TextView tvTitle = convertView.findViewById(R.id.tv_title);
                TextView tvDescription = convertView.findViewById(R.id.tv_description);
                ImageView ivExample = convertView.findViewById(R.id.iv_image);

                ivExample.setImageResource(R.drawable.offer_1);
                tvTitle.setText(elements.get(position));
                tvDescription.setText(String.valueOf(position));

                return convertView;
            }
        }

我在 MainActivity 中添加了一些元素到列表中以查看它是如何工作的，但我很难理解如何添加元素，每个元素都有不同的图片、描述等。

Answer 1

为此，您必须创建一个带有自定义 class 的 ArrayAdapter：以下是您必须遵循的步骤：

创建class自定义

public class Custom {
int image;
String title;
String description;
//constructeur 
//getters and setters }

创建适配器扩展 ArrayAdapter

public class CustomArrayAdapter extends ArrayAdapter<Custom> {

ArrayList<Custom> list;

    public CustomArrayAdapter(Context context, ArrayList<Custom> list) {
    super(context, R.layout.list_item_ex, list);this.list = list;
}


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

    Custom custom=getItem(position);

    if (convertView == null) {
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item_ex, parent, false);
    }

    TextView tvTitle = convertView.findViewById(R.id.tv_title);
    TextView tvDescription = convertView.findViewById(R.id.tv_description);
    ImageView ivExample = convertView.findViewById(R.id.iv_image);

    ivExample.setImageResource(custom.getImage());
    tvTitle.setText(custom.getTitle());
    tvDescription.setText(custom.getDescription());

    return convertView;
}

}

填充一个ArrayList然后listView.setAdapter(customArrayAdapter);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    ListView listView=(ListView) findViewById(R.id.listView) ;
    ArrayList<Custom> list=new ArrayList<>();
    list.add(new Custom(R.mipmap.ic_launcher,"title","desc"));

    CustomArrayAdapter customArrayAdapter=new CustomArrayAdapter(this,listView);

    listView.setAdapter(customArrayAdapter);}

使用 ArrayAdapter 在 Android 中创建列表

Using ArrayAdapter to create a list in Android

android

list

adapter