AsyncTask listview加图片

最新推荐文章于 2018-12-26 14:45:46 发布

李帅磊

最新推荐文章于 2018-12-26 14:45:46 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/lishuaileibo/article/details/78414137

本文介绍了一个具体的Android应用实例，展示了如何使用ListView组件结合自定义适配器实现图文并茂的数据展示，并通过异步任务加载网络数据及图片资源。

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public class MainActivity extends AppCompatActivity {
    String ni="https://www.toutiao.com/api/pc/focus/";
    //图片的网址
    String tu = "https://img-my.youkuaiyun.com/uploads/201407/26/1406383265_8550.jpg";
    private ListView lv;
   private List<Mybean.DataBean.PcFeedFocusBean> list=new ArrayList<>();
    private Myadapter my;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lv = (ListView) findViewById(R.id.lv);
        my = new Myadapter();
        lv.setAdapter(my);

        //ni为网站的地址
        new Myasyntask().execute(ni);

    }
    class Myadapter extends BaseAdapter{

        private ImageView itu;
        private TextView tv;
        private Hodler hodler;

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

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

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

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
           if (view==null){
               hodler = new Hodler();
                view = View.inflate(MainActivity.this, R.layout.lv, null);
               view.setTag(hodler);
           }else{
               hodler = (Hodler) view.getTag();

           }
            hodler.tv = view.findViewById(R.id.tv);
            hodler.tv.setText(list.get(i).getTitle());
            hodler.tv.setText(list.get(i).getTitle());
            hodler.itu = view.findViewById(R.id.tu);
            new Mytuasynctask(hodler.itu).execute(tu);
           return view;
        }
    }
    //listview的优化类
    class Hodler{
        TextView tv;
        ImageView itu;
    }

    //图片的类
    class Mytuasynctask extends AsyncTask<String,Void,Bitmap>{
       private ImageView iv;

        //有参构造的方法
        public Mytuasynctask(ImageView iv) {
            this.iv = iv;
        }

        @Override
        protected Bitmap doInBackground(String... strings) {
            //工具包转Bitmap的方法
            return Myutil.totu(strings[0]);
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            //为图片设置值
           iv.setImageBitmap(bitmap);
        }
    }

    class Myasyntask extends AsyncTask<String,Void,String>{


        @Override
        protected String doInBackground(String... strings) {

            String net= strings[0];
            //工具类解析网站的方法
            String tonet = Myutil.tonet(net);


            return tonet;
        }

        @Override
        protected void onPostExecute(String s) {
            Gson gson = new Gson();
            Mybean mybean = gson.fromJson(s, Mybean.class);
            List<Mybean.DataBean.PcFeedFocusBean> been = mybean.getData().getPc_feed_focus();
            //把集合存放到全局的集合里面
            list.addAll(been);
            //必须刷新适配器
            my.notifyDataSetChanged();
        }
    }
}