XListView实现网络加载图片和下拉刷新

 本文实例为大家分享了XListView实现网络加载图片，和下拉刷新的功能，供大家参考，具体内容如下

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;
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持小牛知识库。