Question

我使用以下代码使用BaseAdapter在ListView上显示图像。代码显示来自drawable文件夹内的图像。但我想修改代码，以便显示以下数组中的远程图像：

  String flags[] ={"http://www.website.com/images/usa.png","http://www.website.com/images/china.png","http://www.website.com/images/australia.png","http://www.website.com/images/portugle.png","http://www.website.com/images/norway.png","http://www.website.com/images/new_zealand.png"};

专家能否告诉我哪些部分需要改变。提前谢谢。

MainActivity.java：

public class MainActivity extends Activity {

    ListView simpleList;
    String countryList[] = {"USA", "China", "australia", "Portugle", "Norway", "NewZealand"};
    int flags[] = {R.drawable.usa, R.drawable.china, R.drawable.australia, R.drawable.portugle, R.drawable.norway, R.drawable.new_zealand};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        simpleList = (ListView) findViewById(R.id.simpleListView);
        CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), countryList, flags);
        simpleList.setAdapter(customAdapter);

        simpleList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                Toast.makeText(getApplicationContext(), "Hello " + countryList[position], Toast.LENGTH_LONG).show();


            }
        });
    }
}

CustomAdapter.java：

Public class CustomAdapter extends BaseAdapter {
    Context context;
    String countryList[];
    int flags[];
    LayoutInflater inflter;

    public CustomAdapter(Context applicationContext, String[] countryList, int[] flags) {
        this.context = context;
        this.countryList = countryList;
        this.flags = flags;
        inflter = (LayoutInflater.from(applicationContext));
    }

    @Override
    public int getCount() {
        return countryList.length;
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view = inflter.inflate(R.layout.activity_listview, null);
        TextView country = (TextView) view.findViewById(R.id.textView);
        ImageView icon = (ImageView) view.findViewById(R.id.icon);
        country.setText(countryList[i]);
        icon.setImageResource(flags[i]);
        return view;
    }
}

Answer 1

你需要：

1）在一个单独的线程中获取这些图像，你可以使用volley，retrofit，robospice。

2）关于来自1）的任何方法的响应，您必须将从服务获得的值列表传递给适配器的构造函数。您需要为模型创建POJO，此结构将包含REST Web服务中的所有元素。

3）建议您为listview的适配器使用视图，以避免一次又一次地夸大视图。

Answer 2

您还可以使用Picasso或Glide等第三方库将图像直接加载到适配器的获取视图方法

Picasso.with（本）.load（标志[适配器的位置]）代入（ImageView的）;

滑翔也一样。

这是简单的教程https://www.simplifiedcoding.net/picasso-android-tutorial-picasso-image-loader-library/

Answer 3

最简单的方法是使用Glide或Picasso：

@Override
public View getView(int i, View view, ViewGroup viewGroup) {
    view = inflter.inflate(R.layout.activity_listview, null);
    TextView country = (TextView) view.findViewById(R.id.textView);
    ImageView icon = (ImageView) view.findViewById(R.id.icon);
    country.setText(countryList[i]);

    // Assuming flags is now the list of Strings of image urls
    GlideApp.with(view.getContext()).load(flags[i]).into(icon);

    return view;
}

如何使用BaseAdapter在ListView中显示远程图像？

3 个答案: