效果图：

第一步：设计

先实现图文加载到列表

 

public class MainActivity extends AppCompatActivity {    private ListView listView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        listView = (ListView) findViewById(R.id.listview);        StringTask task = new StringTask(listView,MainActivity.this);        String url = String.format(Contants.BK_URL,1);        task.execute(url);    }}

public class StringTask extends AsyncTask
     
      
       > {    private ListView listview;    private Context context;    public StringTask(ListView listview, Context context) {        this.listview = listview;        this.context = context;    }    @Override    protected List
       
         doInBackground(String... params) {        String jsonStr = HttpUtils.getJSONStr(params[0]);        List
        
          list = JSONUtils.parseJSON(jsonStr);        return list;    }    @Override    protected void onPostExecute(List
         
           teases) {        TeasAdapter adapter = new TeasAdapter(teases,context);        listview.setAdapter(adapter);        super.onPostExecute(teases);    }}
         
        
       
      
     

public class TeasAdapter extends BaseAdapter {    private List
     
       list;    private Context context;    public TeasAdapter(List
      
        list, Context context) {        this.list = list;        this.context = context;    }    @Override    public int getCount() {        return list.size();    }    @Override    public Object getItem(int position) {        return list.get(position);    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        LayoutInflater inflater = LayoutInflater.from(context);        View view = inflater.inflate(R.layout.list_item, null);        ViewHolder viewHolder = new ViewHolder();        viewHolder.title = (TextView) view.findViewById(R.id.title);        viewHolder.create_time = (TextView) view.findViewById(R.id.creat_time);        viewHolder.image = (ImageView) view.findViewById(R.id.image);        Teas teas = list.get(position);        viewHolder.title.setText(teas.getTitle());        viewHolder.create_time.setText(teas.getCreate_time());        //下载图片并赋值        String image_url = teas.getWap_thumb();        ImageTask task = new ImageTask(viewHolder.image);        task.execute(image_url);        return view;    }    public class ViewHolder{        TextView title,create_time;        ImageView image;    }}
      
     

public class HttpUtils {    //下载数据    public static String getJSONStr(String path){        try {            URL url = new URL(path);            HttpURLConnection conn = (HttpURLConnection) url.openConnection();            int code = conn.getResponseCode();            if(code == 200){                InputStream is = conn.getInputStream();                ByteArrayOutputStream baos = new ByteArrayOutputStream();                byte[] buffer = new byte[1024];                int ret;                while((ret = is.read(buffer))>0){                    baos.write(buffer,0,ret);                }                return baos.toString();            }        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }    //下载图片    public static Bitmap getBitmap(String path){        try {            URL url = new URL(path);            HttpURLConnection conn = (HttpURLConnection) url.openConnection();            int code = conn.getResponseCode();            if(code == 200){                InputStream is = conn.getInputStream();                return BitmapFactory.decodeStream(is);            }        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }}

public class JSONUtils {    //解析json字符串    public static List
     
       parseJSON(String jsonStr){        List
      
        list = new ArrayList
       
        ();        try {            JSONObject object = new JSONObject(jsonStr);            JSONArray array = (JSONArray) object.get("data");            for(int i = 0;i
       
      
     

public class ImageTask extends AsyncTask
     
       {    private ImageView image;    public ImageTask(ImageView image) {        this.image = image;    }    @Override    protected Bitmap doInBackground(String... params) {        Bitmap bitmap = HttpUtils.getBitmap(params[0]);        return bitmap;    }    @Override    protected void onPostExecute(Bitmap bitmap) {        image.setImageBitmap(bitmap);        super.onPostExecute(bitmap);    }}
     

第二步：滑动复用内存空间

优化TeasAdapter的getView方法

@Overridepublic View getView(int position, View convertView, ViewGroup parent) {    ViewHolder viewHolder;    if(convertView == null){        LayoutInflater inflater = LayoutInflater.from(context);        convertView = inflater.inflate(R.layout.list_item, null);        viewHolder = new ViewHolder();        viewHolder.title = (TextView) convertView.findViewById(R.id.title);        viewHolder.create_time = (TextView) convertView.findViewById(R.id.creat_time);        viewHolder.image = (ImageView) convertView.findViewById(R.id.image);        convertView.setTag(viewHolder);    }    viewHolder = (ViewHolder) convertView.getTag();    Teas teas = list.get(position);    viewHolder.title.setText(teas.getTitle());    viewHolder.create_time.setText(teas.getCreate_time());    //下载图片并赋值    String image_url = teas.getWap_thumb();    ImageTask task = new ImageTask(viewHolder.image);    task.execute(image_url);    return convertView;}

第三步：滑动分页

优化MainActivity和StringTask类且在TeasAdapter中增加addData方法

public class MainActivity extends AppCompatActivity {    private TeasAdapter adapter;    private ListView listView;    private boolean flag;    private int index = 1;    private List
     
       list = new ArrayList
      
       ();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        listView = (ListView) findViewById(R.id.listview);        adapter = new TeasAdapter(list,MainActivity.this);        listView.setAdapter(adapter);        StringTask task = new StringTask(adapter);        String url = String.format(Contants.BK_URL,index);        task.execute(url);        //滑动分页        listView.setOnScrollListener(new AbsListView.OnScrollListener() {            @Override            public void onScrollStateChanged(AbsListView view, int scrollState) {                if (flag) {                    index++;                    String new_url = String.format(Contants.BK_URL, index);                    StringTask new_task = new StringTask(adapter);                    new_task.execute(new_url);                }            }            @Override            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {                if (firstVisibleItem + visibleItemCount == totalItemCount) {                    flag = true;                } else {                    flag = false;                }            }        });    }}
      
     

public class StringTask extends AsyncTask
     
      
       > {    private TeasAdapter adapter;    public StringTask(TeasAdapter adapter) {        this.adapter = adapter;    }    @Override    protected List
       
         doInBackground(String... params) {        String jsonStr = HttpUtils.getJSONStr(params[0]);        List
        
          list = JSONUtils.parseJSON(jsonStr);        return list;    }    @Override    protected void onPostExecute(List
         
           teases) {        adapter.addData(teases);        super.onPostExecute(teases);    }}
         
        
       
      
     

public void addData(List
     
       teas){        list.addAll(teas);        notifyDataSetChanged();    }
     

第四步：保存图片加缓存，保存到sd卡且防止图片加载错位

（先在缓存查找图片，再去sdcard查找，如果没有，网络下载，然后保存到sdcard，最后保存到缓存）

优化TeasAdapter和ImageTask类

public class TeasAdapter extends BaseAdapter {    private List
     
       list;    private Context context;    private LruCache
      
        cache;    public TeasAdapter(List
       
         list, Context context) {        this.list = list;        this.context = context;        long maxMemory = Runtime.getRuntime().maxMemory();        cache = new LruCache
        
         ((int) (maxMemory/8)){            @Override            protected int sizeOf(String key, Bitmap value) {                return value.getByteCount()*value.getHeight();            }        };    }    @Override    public int getCount() {        return list.size();    }    @Override    public Object getItem(int position) {        return list.get(position);    }    @Override    public long getItemId(int position) {        return position;    }    //滑动复用内存空间    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder viewHolder;        if(convertView == null){            LayoutInflater inflater = LayoutInflater.from(context);            convertView = inflater.inflate(R.layout.list_item, null);            viewHolder = new ViewHolder();            viewHolder.title = (TextView) convertView.findViewById(R.id.title);            viewHolder.create_time = (TextView) convertView.findViewById(R.id.creat_time);            viewHolder.image = (ImageView) convertView.findViewById(R.id.image);            convertView.setTag(viewHolder);        }        viewHolder = (ViewHolder) convertView.getTag();        Teas teas = list.get(position);        viewHolder.title.setText(teas.getTitle());        viewHolder.create_time.setText(teas.getCreate_time());        //下载图片并赋值        String image_url = teas.getWap_thumb();        Bitmap bitmap = cache.get("image_url");        //判断是否在缓存中        if(bitmap!=null){            viewHolder.image.setImageBitmap(bitmap);        }else{            viewHolder.image.setTag(image_url);            ImageTask task = new ImageTask(viewHolder.image,context,cache);            task.execute(image_url);        }        return convertView;    }    public class ViewHolder{        TextView title,create_time;        ImageView image;    }    public void addData(List
         
           teas){        list.addAll(teas);        notifyDataSetChanged();    }}
         
        
       
      
     

public class ImageTask extends AsyncTask
     
       {    private String image_url;    private ImageView image;    private Context context;    private LruCache
      
        cache;    public ImageTask(ImageView image, Context context, LruCache
       
         cache) {        this.image = image;        this.context = context;        this.cache = cache;    }    @Override    protected Bitmap doInBackground(String... params) {        image_url = params[0];        File file = context.getCacheDir();        File file2 = new File(file,image_url);        //判断是否在sdcard中        if(file2.exists()){            return BitmapFactory.decodeFile(file2.getAbsolutePath());        }else{            Bitmap bitmap = HttpUtils.getBitmap(image_url);            try {                //保存到sdcard中                FileOutputStream fos = new FileOutputStream(file2);                bitmap.compress(Bitmap.CompressFormat.JPEG,100,fos);            } catch (FileNotFoundException e) {                e.printStackTrace();            }            return bitmap;        }    }    @Override    protected void onPostExecute(Bitmap bitmap) {        if(bitmap!=null){            //保存到内存中            cache.put(image_url, bitmap);            String url = (String) image.getTag();            if(url.equals(image_url)){                image.setImageBitmap(bitmap);            }        }        super.onPostExecute(bitmap);    }}