Json緩存到SdCard裏

public class MainActivity extends AppCompatActivity {

    private Handler handler=new Handler(){

        @Override
        public void handleMessage(Message msg) {

            adlist = (List<InfoBean.DataBean.AdlistBean>) msg.obj;
            MyAdapter adapter = new MyAdapter();
            lv.setAdapter(adapter);

        }
    };
    private ListView lv;
    private List<InfoBean.DataBean.AdlistBean> adlist;
    private DisplayImageOptions options;
    private SharedPreferences sp;

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

        lv = (ListView) findViewById(R.id.lv);

        sp = getSharedPreferences("config", MODE_PRIVATE);
        options = new DisplayImageOptions.Builder()
                .showImageOnLoading(R.mipmap.ic_launcher)
                .cacheInMemory(true)
                .cacheOnDisk(true)
                .build();

        if (sp.getString("json",null)==null){
            Toast.makeText(this, "第一次", Toast.LENGTH_SHORT).show();
            new Thread(){

                @Override
                public void run() {
                    super.run();

                    String json = NetWork.getJson();
                    sp.edit().putString("json",json).commit();
                    getGsonData(json);
                    // Toast.makeText(MainActivity.this,json,Toast.LENGTH_LONG).show();
                }

            }.start();
        }else{
            Toast.makeText(this, "第二次有緩存了", Toast.LENGTH_SHORT).show();
            String json=sp.getString("json",null);
            getGsonData(json);
        }



    }

    class MyAdapter extends BaseAdapter{

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

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder;
            if (convertView==null){
                holder = new ViewHolder();
                convertView=View.inflate(MainActivity.this,R.layout.list_item,null);
                holder.iv= (ImageView) convertView.findViewById(R.id.iv);
                holder.tv= (TextView) convertView.findViewById(R.id.tv);
                convertView.setTag(holder);
            }else {
                holder= (ViewHolder) convertView.getTag();
            }
            ImageLoader.getInstance().displayImage(adlist.get(position).getImg(),holder.iv,options);
            holder.tv.setText(adlist.get(position).getName());
            return convertView;
        }
        class ViewHolder{
            ImageView iv;
            TextView tv;
        }
    }

    private void getGsonData(String json) {
        Gson gson = new Gson();
        InfoBean infoBean = gson.fromJson(json, InfoBean.class);
        List<InfoBean.DataBean.AdlistBean> adlist = infoBean.getData().getAdlist();
        Message message = new Message();
        message.obj=adlist;
        handler.sendMessage(message);

    }
}

//《2、》進行網絡請求

public class NetWork {


    public static  String getJson(){

        String path="http://www.meirixue.com/api.php?c=index&a=index";

        try {
            URL url = new URL(path);
            HttpURLConnection connection = (HttpURLConnection) url
                    .openConnection();
            connection.setConnectTimeout(5000);
            connection.setReadTimeout(5000);
            int responseCode = connection.getResponseCode();

            byte[] arr = new byte[1024];
            int len;
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            if (responseCode == 200) {
                InputStream inputStream = connection.getInputStream();

                while ((len=inputStream.read(arr))!=-1){
                    baos.write(arr,0,len);
                }


                return baos.toString();
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    }
}

//<3>Application配置圖片

public class MyApplication extends Application {

    @Override
    public void onCreate() {
        super.onCreate();

        ImageLoaderConfiguration configuration=new ImageLoaderConfiguration.Builder(this)
                .threadPoolSize(3)
                .memoryCacheSize(1024*2)
                .build();
        ImageLoader.getInstance().init(configuration);

    }
}