如何在 Android 中使用 ListAdapter？

Question

我正在使用库asymmetricGridView， 给出的代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    listView = (AsymmetricGridView) findViewById(R.id.listView);

    // Choose your own preferred column width
    listView.setRequestedColumnWidth(Utils.dpToPx(this, 120));
    final List<AsymmetricItem> items = new ArrayList<>();

    // initialize your items array
    adapter = new ListAdapter(this, listView, items);
    AsymmetricGridViewAdapter asymmetricAdapter =
        new AsymmetricGridViewAdapter<>(this, listView, adapter);
    listView.setAdapter(asymmetricAdapter);
}

我在适配器中遇到错误 = new ListAdapter(this, listView, items); 我不知道如何使用 ListAdapter，我是 android 新手，有人可以帮我做吗？

Answer 1

ListAdapter 是 interface，而不是 class。你不能用new 来实例化它，除非你在实例化的时候定义了一个匿名的内部类。

我建议您搜索有关使用 ListAdapter（以及一般 Android 上的适配器）的教程。我还建议您使用来自同一个库的AsymmetricRecyclerView（因此也使用AsymmetricRecyclerViewAdapter），因为ListView 相当陈旧且笨重，它的功能或多或少已被RecyclerView 取代。

Answer 2

这是结果

第 1 步：创建类 Events。

import java.io.Serializable;

public class Events implements Serializable {

    private String id;
    private String titleEvent;
    private String dateEvent;

    public Events() {

    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getTitleEvent() {
        return titleEvent;
    }

    public void setTitleEvent(String titleEvent) {
        this.titleEvent = titleEvent;
    }

    public String getDateEvent() {
        return dateEvent;
    }

    public void setDateEvent(String dateEvent) {
        this.dateEvent = dateEvent;
    }
}

第二步：创建类ListAdapter extends ArrayAdapter<Events>

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;


import com.info.quanglv.eventlucky.R;
import com.info.quanglv.eventlucky.common.Events;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;


public class ListAdapter extends ArrayAdapter<Events> {

    List<Events> listProduct = new ArrayList<>();

    public ListAdapter(Context context, int resource, List<Events> objects) {
        super(context, resource, objects);
        listProduct = objects;
    }


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

        View view = convertView;
        if (view == null) {
            LayoutInflater inflater = LayoutInflater.from(getContext());
            view = inflater.inflate(R.layout.item_events, null);
        }
        Events events = getItem(position);

        if (events != null) {

            TextView txt_Title = (TextView) view.findViewById(R.id.txtTitleEvent);
            txt_Title.setText(events.getTitleEvent());
            TextView txt_dateEvent = (TextView) view.findViewById(R.id.txtDateEvent);
            txt_dateEvent.setText(events.getDateEvent());
            //ImageView img_Product = (ImageView) view.findViewById(R.id.imgProduct);
            // img_Product.setImageResource(position);
            // img_Product.setImageURI(product.getImg());
            // new DownloadImageTask(img_Product).execute(listProduct.get(position).getImageProduct());
        }
        return view;
    }


    public static class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
        ImageView bmImage;

        public DownloadImageTask(ImageView bmImage) {
            this.bmImage = bmImage;
        }

        protected Bitmap doInBackground(String... urls) {
            String urldisplay = urls[0];
            Bitmap mIcon = null;
            try {
                InputStream in = new java.net.URL(urldisplay).openStream();
                mIcon = BitmapFactory.decodeStream(in);
            } catch (Exception e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return mIcon;
        }

        protected void onPostExecute(Bitmap result) {
            bmImage.setImageBitmap(result);
        }
    }
}

第 3 步：在onCreate() 中，您可以编码： 新的 GetListProduct().execute();

private class GetListProduct extends AsyncTask<Void, Void, ArrayList<Events>> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected ArrayList<Events> doInBackground(Void... params) {
        ArrayList<Events> events = new ArrayList<>();

        Events eventsLucky = new Events();
        eventsLucky.setId("1");
        eventsLucky.setTitleEvent("New Year CountDown Party");
        eventsLucky.setDateEvent("10/10/12");
        events.add(eventsLucky);

        Events eventsLucky1 = new Events();
        eventsLucky1.setId("2");
        eventsLucky1.setTitleEvent("Tiger Remix Concert 2016 ");
        eventsLucky1.setDateEvent("10/10/12");
        events.add(eventsLucky1);

        Events eventsLucky2 = new Events();
        eventsLucky2.setId("3");
        eventsLucky2.setTitleEvent("Tiger Remix Concert 2016 ");
        eventsLucky2.setDateEvent("10/10/1212");
        events.add(eventsLucky2);

        Events eventsLucky3 = new Events();
        eventsLucky3.setId("4");
        eventsLucky3.setTitleEvent("Tiger Remix Concert 2016 ");
        eventsLucky3.setDateEvent("10/10/1212");
        events.add(eventsLucky3);

        return events;
    }

    @Override
    protected void onPostExecute(ArrayList<Events> events) {
        super.onPostExecute(events);
        listView = (ListView) findViewById(R.id.listView);

        ListAdapter listAdapter = new ListAdapter(HomeActivity.this, R.layout.activity_home_activiy, events);
        listView.setAdapter(listAdapter);

    }
}

第四步：在onCreate()下插入代码

private class GetListProduct extends AsyncTask<Void, Void, ArrayList<Events>> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected ArrayList<Events> doInBackground(Void... params) {
        ArrayList<Events> events = new ArrayList<>();

        Events eventsLucky = new Events();
        eventsLucky.setId("1");
        eventsLucky.setTitleEvent("New Year CountDown Party");
        eventsLucky.setDateEvent("10/10/12");
        events.add(eventsLucky);

        Events eventsLucky1 = new Events();
        eventsLucky1.setId("2");
        eventsLucky1.setTitleEvent("Tiger Remix Concert 2016 ");
        eventsLucky1.setDateEvent("10/10/12");
        events.add(eventsLucky1);

        Events eventsLucky2 = new Events();
        eventsLucky2.setId("3");
        eventsLucky2.setTitleEvent("Tiger Remix Concert 2016 ");
        eventsLucky2.setDateEvent("10/10/1212");
        events.add(eventsLucky2);

        Events eventsLucky3 = new Events();
        eventsLucky3.setId("4");
        eventsLucky3.setTitleEvent("Tiger Remix Concert 2016 ");
        eventsLucky3.setDateEvent("10/10/1212");
        events.add(eventsLucky3);

        return events;
    }

    @Override
    protected void onPostExecute(ArrayList<Events> events) {
        super.onPostExecute(events);
        listView = (ListView) findViewById(R.id.listView);
        ListAdapter listAdapter = new ListAdapter(HomeActivity.this, R.layout.activity_home_activiy, events);
        listView.setAdapter(listAdapter);
    }
}