HttpClient+图片加载+工具类+接口回调+AsyncTask封装到工具类

1.MainActivity页面

package com.example.httpclient;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity {

    private ListView listView;
    private NewsAdaper mAdaper;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取资源id
        listView = findViewById(R.id.listview);
        //创建适配器
        mAdaper = new NewsAdaper(MainActivity.this);
        //将适配器赋给listview
        listView.setAdapter(mAdaper);
        //获取数据的方法
        infoData();
    }
    private String urlStr = "http://api.expoon.com/AppNews/getNewsList/type/1/p/1";
    //获取数据的方法
    private void infoData() {
        NetUtil.getResult(urlStr, NewsBean.class, new NetUtil.CallBack2<NewsBean>() {
            @Override
            public void onSuccess(NewsBean object) {
                mAdaper.setmData(object.getData());
            }
        });
    }
}

2.Bean类

package com.example.httpclient;

import java.util.List;

public class NewsBean {

    private List<DataBean> data;

    public List<DataBean> getData() {
        return data;
    }

    public void setData(List<DataBean> data) {
        this.data = data;
    }

    public static class DataBean {
     
        private String news_id;
        private String news_title;
        private String news_summary;
        private String pic_url;

        public String getNews_id() {
            return news_id;
        }

        public void setNews_id(String news_id) {
            this.news_id = news_id;
        }

        public String getNews_title() {
            return news_title;
        }

        public void setNews_title(String news_title) {
            this.news_title = news_title;
        }

        public String getNews_summary() {
            return news_summary;
        }

        public void setNews_summary(String news_summary) {
            this.news_summary = news_summary;
        }

        public String getPic_url() {
            return pic_url;
        }

        public void setPic_url(String pic_url) {
            this.pic_url = pic_url;
        }
    }
}

3.适配器类

package com.example.httpclient;

import android.content.Context;
import android.graphics.Bitmap;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class NewsAdaper extends BaseAdapter {
    private List<NewsBean.DataBean> mData;
    private Context mContext;
    public NewsAdaper(Context mContext) {
        this.mContext = mContext;
        //初始化
        mData = new ArrayList<>();
    }
    public void setmData(List<NewsBean.DataBean> datas){
        this.mData = datas;
        notifyDataSetChanged();
    }
    @Override
    public int getCount() {
        return mData.size();
    }

    @Override
    public NewsBean.DataBean getItem(int position) {
        return mData.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        //判断convertView是否为空
        if(convertView == null){
            //加载子布局
            convertView = LayoutInflater.from(mContext).inflate(R.layout.item,parent,false);
            //实例化viewholder
            holder = new ViewHolder(convertView);
        }else{
            //复用
            holder = (ViewHolder) convertView.getTag();
        }
        holder.bind(getItem(position));
        return convertView;
    }
    //寄存器
    class ViewHolder{
        ImageView image;
        TextView text1;
        TextView text2;
        //获取资源id
        public ViewHolder(View convertView) {
            image = convertView.findViewById(R.id.image);
            text1 = convertView.findViewById(R.id.text1);
            text2 = convertView.findViewById(R.id.text2);
            convertView.setTag(this);
        }
        //赋值
        public void bind(final NewsBean.DataBean item) {
            text1.setText(item.getNews_title());
            text2.setText(item.getNews_summary());
            image.setTag(item.getPic_url());
            NetUtil.loadImage(item.getPic_url(), new NetUtil.CallBack() {
                @Override
                public void imageSuccess(String urlImage, Bitmap bitmap) {
                    if(image.getTag().equals(item.getPic_url())){
                        image.setImageBitmap(bitmap);
                    }
                }
            });
        }
    }
}

4.工具类

package com.example.httpclient;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.LruCache;

import com.google.gson.Gson;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.methods.RequestBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
public class NetUtil {
    //图片内存缓存
    private static LruCache<String,Bitmap> cache;
    private static File saveDir;
    //私有构造方法
    private NetUtil(Context context){
        int siez = (int)(Runtime.getRuntime().freeMemory()*0.3);
        cache = new LruCache<>(siez);
        //图片文件缓存目录
        saveDir = new File(context.getCacheDir(),"imag_cache");
        //不存在创建
        if(!saveDir.exists()){
            saveDir.mkdirs();
        }
    }
    //Httpclietn网络请求返回string
    public static String getResult(String url){
        String json = "";
        try {
            //创建client
            HttpClient client = HttpClients.createDefault();
            HttpUriRequest request = RequestBuilder.get().setUri(url).build();
            HttpResponse response = client.execute(request);
            if(response.getStatusLine().getStatusCode() == 200){
               json = EntityUtils.toString(response.getEntity());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return json;
    }
    //解析gson返回 bean
    public static <E> E getResult(String url,Class clazz){
        String result = getResult(url);
        E e = (E) new Gson().fromJson(result,clazz);
        return e;
    }
    //加载网络图片
    public static Bitmap loadImage(String urlImage){
        Bitmap bitmap = null;
        try {
            //定义url地址
            URL url = new URL(urlImage);
            //设置请求方式
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            //设置超时
            urlConnection.setConnectTimeout(5000);
            urlConnection.setReadTimeout(5000);
            //获取请求类型
            int responseCode = urlConnection.getResponseCode();
            if(responseCode == 200){
                bitmap = BitmapFactory.decodeStream(urlConnection.getInputStream());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return bitmap;
    }
    //定义接口
    public interface CallBack{
        void imageSuccess(String urlImage,Bitmap bitmap);
    }
    //获取图片 接口回调
    public static void loadImage(final String urlImage,final CallBack callBack){
        new AsyncTask<String,Void,Bitmap>(){
            @Override
            protected Bitmap doInBackground(String... strings) {
                return loadImage(strings[0]);
            }

            @Override
            protected void onPostExecute(Bitmap bitmap) {
                callBack.imageSuccess(urlImage,bitmap);
            }
        }.execute(urlImage);
    }
    //获取图片
    public static Bitmap loadImageWork(String urlImage){
        Bitmap result = null;
        //从内存中取图片
        result = cache.get(url2Key(urlImage));
        //文件存在
        if(result!=null){
            return result;
        }
        //从磁盘中取图片
        result = getBitmapForFile(urlImage);
        //文件存在
        if(result!=null){
            cache.put(url2Key(urlImage),result);
            return result;
        }
        //从网络中获取图片
        result = loadImage(urlImage);
        //写文件
        saveBitmap2File(urlImage,result);
        //存到内存缓存
        cache.put(url2Key(urlImage),result);
        return result;
    }
    //将图片存到文件
    private static void saveBitmap2File(String urlImage, Bitmap bitmap) {
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(new File(saveDir,url2Key(urlImage)));
            //图片质量压缩，并输出到输出流
            bitmap.compress(Bitmap.CompressFormat.JPEG,100,fos);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }finally {
            if(fos!=null){
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    //从文件读取图片
    private static Bitmap getBitmapForFile(String urlImage) {
        //解码文件为bitmap图片
        return BitmapFactory.decodeFile(new File(saveDir,url2Key(urlImage)).getAbsolutePath());
    }
    //将url转换成key
    private static String url2Key(String urlImage) {
        return String.valueOf(urlImage.hashCode());
    }

    //定义接口
    public interface CallBack2<E>{
        void onSuccess(E object);
    }
    //执行线程的方法
    public static void getResult(String url, final Class clazz, final CallBack2 callBack2){
        new AsyncTask<String,Void,Object>(){
            @Override
            protected Object doInBackground(String... strings) {
                return NetUtil.getResult(strings[0],clazz);
            }

            @Override
            protected void onPostExecute(Object o) {
                callBack2.onSuccess(o);
            }
        }.execute(url);
    }

}