XListView实现网络加载图片和下拉刷新

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();
}
}

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;
}
}