XListView网络加载图片，下拉刷新

MainActivity.java

public class MainActivity extends AppCompatActivity {

  private XListView contents;

  private int page = 0;
  private MyBaseAdapter adapter;

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

    contents = findViewById(R.id.contents);
    adapter = new MyBaseAdapter(getLayoutInflater());
    contents.setAdapter(adapter);

    //是否开启下拉刷新 上拉加载
    //contents.setPullRefreshEnable(false);
    contents.setPullLoadEnable(true);

    contents.setXListViewListener(new XListView.IXListViewListener() {
      @Override public void onRefresh() {
        page = 0;
        loadData(page);
        //加载刷新数据
      }

      @Override public void onLoadMore() {
        loadData(page);
      }
    });

    //一进来就去加载第一页数据
    loadData(page);
  }

  private String url =
      "http://apis.juhe.cn/cook/query?key=3ec004200a6a2f4cf4774e480c006375&menu=%E8%A5%BF%E7%BA%A2%E6%9F%BF&rn=10&pn=";

  private void loadData(int page) {
    String requestUrlWithPageNum = url + page;

    //加载网络数据
    new AsyncTask<String, Void, List<DataItem>>() {

      @Override protected List<DataItem> doInBackground(String... strings) {
        ResponseBean responseBean = null;
        try {
          URL url = new URL(strings[0]);
          HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
          urlConnection.setRequestMethod("GET");
          urlConnection.setConnectTimeout(5000);
          urlConnection.setReadTimeout(5000);

          int responseCode = urlConnection.getResponseCode();
          if (responseCode == 200) {
            String str = stream2String(urlConnection.getInputStream());
            responseBean = new Gson().fromJson(str, ResponseBean.class);
          } else {
            //
          }
          return responseBean == null ? null : responseBean.getResult().getData();
        } catch (MalformedURLException e) {
          e.printStackTrace();
        } catch (IOException e) {
          e.printStackTrace();
        }

        return null;
      }

      @Override protected void onPostExecute(List<DataItem> dataItems) {
        if (dataItems == null) {
          Toast.makeText(MainActivity.this, "请求数据错误", Toast.LENGTH_LONG).show();
          return;
        }

        //更新数据
        updateData(dataItems);
        loadCompleted();
      }
    }.execute(url);
  }

  private String stream2String(InputStream is) throws IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();
    for (String tmp = br.readLine(); tmp != null; tmp = br.readLine()) {
      sb.append(tmp);
    }

    return sb.toString();
  }

  private void updateData(List<DataItem> datas) {
    if (page == 0) {
      adapter.setDatas(datas);
    } else {
      adapter.addDatas(datas);
    }
  }

  //通过 加载 / 刷新 完成
  private void loadCompleted() {
    //通过ListView：刷新、加载完成
    page++;
    contents.stopLoadMore();
    contents.stopRefresh();
  }
}

MyBaseAdapter.java

public class MyBaseAdapter extends BaseAdapter {

  private List<DataItem> mDatas;
  protected LayoutInflater mInflater;

  /**
   * 更新数据
   */
  public void setDatas(List<DataItem> datas) {
    mDatas.clear();
    if (datas != null) {
      mDatas.addAll(datas);
    }
    notifyDataSetChanged();
  }

  /**
   * 追加数据
   */
  public void addDatas(List<DataItem> datas) {
    if (datas != null) {
      mDatas.addAll(datas);
      notifyDataSetChanged();
    }
  }

  public MyBaseAdapter(LayoutInflater mInflater) {
    this.mInflater = mInflater;
    mDatas = new ArrayList<>();
  }

  @Override public int getCount() {
    return mDatas.size();
  }

  @Override public DataItem getItem(int position) {
    return mDatas.get(position);
  }

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

  @Override public View getView(int position, View convertView, ViewGroup parent) {
    BaseViewHolder viewHolder = null;

    if (convertView == null) {
      convertView = mInflater.inflate(R.layout.item, parent, false);
      viewHolder = new BaseViewHolder(convertView);
    } else {
      viewHolder = (BaseViewHolder) convertView.getTag();
    }

    viewHolder.bindData(getItem(position));

    return convertView;
  }

  public class BaseViewHolder {
    private View itemView;

    private ImageView icon;
    private TextView title;
    private TextView date;

    public BaseViewHolder(View itemView) {
      this.itemView = itemView;
      title = itemView.findViewById(R.id.title);
      date = itemView.findViewById(R.id.date);
      icon = itemView.findViewById(R.id.icon);

      itemView.setTag(this);
    }

    public void bindData(DataItem dataItem) {
      title.setText(dataItem.getTitle());
      date.setText(dataItem.getId());
      ImageLoader.getInstance().displayImage(dataItem.getFirstImageUrl(), icon,
          ImageLoaderConfigs.getDefaultDisplayImageOptions(icon.getContext()));
    }
  }
}
ImageLoader.java
    public class ImageLoaderConfigs {
  public static ImageLoaderConfiguration getImageLoaderConfiguration(Context context) {
    ImageLoaderConfiguration configuration = new ImageLoaderConfiguration.Builder(context)
        //内在缓存额外选项， 最大的宽度，高度
        //.memoryCacheExtraOptions(480, 800) // default = device screen dimensions 内存缓存文件的最大长宽
        //.diskCacheExtraOptions(480, 800, null)  // 本地缓存的详细信息(缓存的最大长宽)，最好不要设置这个
        //线程池配置
        //.taskExecutor()
        //.taskExecutorForCachedImages()
        //.threadPoolSize(3) // default  线程池内加载的数量
        //.threadPriority(Thread.NORM_PRIORITY - 2) // default 设置当前线程的优先级
        //任务处理优先级 Fist In Fist Out
        //.tasksProcessingOrder(QueueProcessingType.FIFO) // default
        //内存中不缓存一张图片的多个尺寸大小
        //.denyCacheImageMultipleSizesInMemory()
        //内在缓存策略
        //.memoryCache(new LruMemoryCache(2 * 1024 * 1024)) //可以通过自己的内存缓存实现
        //内存缓存大小
        //.memoryCacheSize(2 * 1024 * 1024)  // 内存缓存的最大值
        //内在缓存大小：占用百分比
        .memoryCacheSizePercentage(13) // default
        //磁盘缓存策略
        //.diskCache(new LruDiskCache()) // default 可以自定义缓存路径
        //磁盘缓存大小
        .diskCacheSize(50 * 1024 * 1024) // 50 Mb sd卡(本地)缓存的最大值
        //.diskCacheFileCount(100)  // 可以缓存的文件数量
        // default为使用HASHCODE对UIL进行加密命名， 还可以用MD5(new Md5FileNameGenerator())加密
        //.diskCacheFileNameGenerator(new HashCodeFileNameGenerator())
        //.imageDownloader(new BaseImageDownloader(context)) // default
        //(new BaseImageDecoder(false)) // default
        //加载具体图片时的一些配置
        .defaultDisplayImageOptions(DisplayImageOptions.createSimple()) // default
        .writeDebugLogs() // 打印debug log
        .build();

    return configuration;
  }

  public static DisplayImageOptions getDefaultDisplayImageOptions(Context context) {
    DisplayImageOptions displayImageOptions = new DisplayImageOptions.Builder()
        //是否缓存
        .cacheInMemory(true)
        .cacheOnDisk(true)
        //RGB 565   r红色占5   g绿色占6   b蓝色占5  -> 2字节
        //alpha
        //ARGB 4444    4 4 4 4  -> 2字节
        //ARGB 8888    -> 4字节

        //10 * 10 用rgb565 -> 10*10*2

        .bitmapConfig(Bitmap.Config.RGB_565)
        //加载时、加载错误时展示什么内容
        .showImageOnLoading(R.mipmap.ic_launcher)
        .showImageOnFail(R.mipmap.ic_launcher)
        //
        .imageScaleType(ImageScaleType.EXACTLY_STRETCHED)

        //加载效果
        //ctrl + p
        .displayer(new CircleBitmapDisplayer())
        .build();

    //ctrl + h
    //BitmapDisplayer;
    return displayImageOptions;
  }
}