用Handler和AsyncTask和广播获取数据展示页面

先写一个Handler

 @SuppressLint("HandlerLeak")
    Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            if(msg.what==0){
                String json= (String) msg.obj;

                Toast.makeText(getActivity(),json.toString(),Toast.LENGTH_LONG).show();
                try {
                    JSONObject jsonObject = new JSONObject(json);
                    JSONArray data = jsonObject.getJSONArray("data");
                    listView.setAdapter(new MyAdapter(getActivity(),data));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    };

在onCreateView中进行广播

 receiver = new MyBroadcastReceiver();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);
        getActivity().registerReceiver(receiver,intentFilter);

用广播方法进行判断

//定义广播监听网络状态
    private class MyBroadcastReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            //判断是否有网
            boolean b = NetWorkUtils.isNetWorkConnection(context);
            //有网识别网络类型
            if(b){
                //调用网络请求方法
                getHttpData();
                boolean wifi = NetWorkUtils.isWifi(context);
                if(wifi){
                    Toast.makeText(context, "wifi", Toast.LENGTH_SHORT).show();
                }
                boolean mobile = NetWorkUtils.isMobile(context);
                if(mobile){
                    Toast.makeText(context, "mobile", Toast.LENGTH_SHORT).show();
                }

            }else{
                //没网 -----弹框-----设置网络提示
                AlertDialog.Builder builder = new AlertDialog.Builder(context);
                builder.setTitle("网络提示");
                builder.setMessage("当前网络不可用");
                //确认按钮
                builder.setPositiveButton("设置", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                    //去设置界面
                    startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));
                    }
                });
                //no按钮
                builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {

                    }
                });
                builder.show();
            }
        }
    }

获取数据

    private void getHttpData() {
        new Thread(new Runnable() {
            @Override
            public void run() {

                //创建url
                String path = "http://www.xieast.com/api/news/news.php";
                try {
                    URL url = new URL(path);
                    //打开网络连接
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                    //设置请求方式
                    conn.setRequestMethod("GET");
                    //延时
                    conn.setConnectTimeout(5000);
                    //获取状态码
                    int code = conn.getResponseCode();
                    if(code==200){
                            //获取网络资源
                        InputStream inputStream = conn.getInputStream();
                        //创建字节输出流
                        ByteArrayOutputStream bos = new ByteArrayOutputStream();
                        byte[] buffer = new byte[1024];
                        int len=0;
                        while ((len=inputStream.read(buffer))!=-1){
                            bos.write(buffer,0,len);
                        }
                        //发送消息
                        String json = bos.toString();
                        Message message = new Message();
                        message.obj=json;
                        message.what=0;
                        handler.sendMessage(message);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }


    @Override
    public void onDestroy() {
        super.onDestroy();
        getActivity().unregisterReceiver(receiver);
    }

在另一个页面

 public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view  = inflater.inflate(R.layout.frag02,null,false);
        listView = view.findViewById(R.id.listview_2);
        MyAsyncTask myAsyncTask = new MyAsyncTask();
        myAsyncTask.execute(path);
        return view;
    }

//AsyncTask

 private class MyAsyncTask extends AsyncTask<String,Void,String> {
        //接收path参数
        @Override
        protected String doInBackground(String... strings) {
           String url =  strings[0];
            //创建URL
            try {
                URL url1 = new URL(path);
                HttpURLConnection connection = (HttpURLConnection) url1.openConnection();
                //请求方法
                connection.setRequestMethod("GET");
                connection.setConnectTimeout(5000);
                //状态码
                int responseCode = connection.getResponseCode();
                if(responseCode==200){
                    //获取网络数据
                    InputStream inputStream = connection.getInputStream();
                    //创建字节输出流
                    ByteArrayOutputStream bos = new ByteArrayOutputStream();
                    byte[] buffer = new byte[1024];
                    int len=0;
                    while ((len=inputStream.read(buffer))!=-1){
                        bos.write(buffer,0,len);
                    }
                    //关流
                    inputStream.close();
                    bos.close();
                    String json = bos.toString();
                    return json;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            Gson gson = new Gson();
            JsonBean jsonBean = gson.fromJson(s, JsonBean.class);
            ArrayList<Data> data = jsonBean.getData();
            //适配器
            listView.setAdapter(new MyAdapter_2(getActivity(),data));
        }
    }