android_判断网络/添加Fragment显示listview

权限:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>    <uses-permission android:name="android.permission.INTERNET"></uses-permission>

布局控件:

activity_main:  写fragment时  除了要写name外 还要写id 不然会报错因为id是fragment唯一标识

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout    xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"    android:layout_height="match_parent" tools:context="com.bwei.day_14rikao.MainActivity">    <fragment        android:id="@+id/ff"        android:name="com.bwei.day_14rikao.BeaseFragmrnt"        android:layout_width="match_parent"        android:layout_height="match_parent"></fragment></android.support.constraint.ConstraintLayout>

fragment:

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <ListView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/lv"/></LinearLayout>MainActivity:Fragment:
package com.bwei.day_14rikao;import android.app.Activity;import android.app.AlertDialog;import android.content.Context;import android.content.DialogInterface;import android.content.Intent;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.os.AsyncTask;import android.os.Bundle;import android.provider.Settings;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.TextView;import com.google.gson.Gson;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.util.ArrayList;import java.util.List;/** * author:Created by WangZhiQiang on 2017/9/14. */public class BeaseFragmrnt extends Fragment {    private List<String> lists;    private View view;    private ListView lv;    private StringBuilder builder;    private List<List<String>> result;    ArrayList<String> list = new ArrayList<>();    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        view = inflater.inflate(R.layout.fragment, container, false);        return view;    }    @Override    public void onActivityCreated(@Nullable Bundle savedInstanceState) {        super.onActivityCreated(savedInstanceState);        //初始化控件        lv = (ListView) view.findViewById(R.id.lv);        //获取判断网络返回值        boolean b = isNetworkConnected(getActivity());        Log.e("gsyfdgvsydhfbsjh", b + "");        //判断是否连接网络        if (b) {            //如果返回true则加载数据            new MAsticy().execute("https://suggest.taobao.com/sug?code=utf-8&q=%E6%98%BE%E7%A4%BA%E5%99%A8");        } else {            //否则调用此方法进行下一步操作            checkNetwork(getActivity());        }    }    public class MAsticy extends AsyncTask<String, Void, String> {        @Override        protected String doInBackground(String... strings) {            try {                //获取路径                    URL url = new URL(strings[0]);                //获取 HttpURLConnection对象                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();                //获取请求码                    int responseCode = urlConnection.getResponseCode();                //判断请求码                    if (responseCode == 200) {                        //将路径转换字节流获取                        InputStream inputStream = urlConnection.getInputStream();                        //使用bufferReader读取                        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));                        //拼接字符串                        builder = new StringBuilder();                        //定义变量                        String str = "";                        //循环读取                        while ((str = bufferedReader.readLine()) != null) {                            //拼接                            builder.append(str);                        }                }                //返回                return builder.toString();            } catch (MalformedURLException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            }            return null;        }        @Override        protected void onPreExecute() {            super.onPreExecute();        }        @Override        protected void onPostExecute(String s) {            //创建gson对象            Gson gson = new Gson();            //解析gson串            GsonBean gsonBean = gson.fromJson(s, GsonBean.class);            //获取数据            result = gsonBean.getResult();            //遍历集合            for (int i = 0; i < result.size(); i++) {                lists = result.get(i);                //添加到新集合                list.addAll(lists);            }            //设置适配器            lv.setAdapter(new MAdapter());            super.onPostExecute(s);        }        @Override        protected void onProgressUpdate(Void... values) {            super.onProgressUpdate(values);        }    }    private class MAdapter extends BaseAdapter {        @Override        public int getCount() {            return list.size();        }        @Override        public Object getItem(int i) {            return list.get(i);        }        @Override        public long getItemId(int i) {            return i;        }        @Override        public View getView(int i, View view, ViewGroup viewGroup) {            ViewHolder holder;            String s = list.get(i);            if (view == null) {                view = View.inflate(getActivity(), android.R.layout.simple_list_item_1, null);                holder = new ViewHolder();                holder.text1 = (TextView) view.findViewById(android.R.id.text1);                view.setTag(holder);            } else {                holder = (ViewHolder) view.getTag();            }            holder.text1.setText(s);            return view;        }        class ViewHolder {            TextView text1;        }    }    //////////////////////////////////////    //创建网络请求方法    public boolean isNetworkConnected(Context context) {        if (context != null) {            ConnectivityManager mConnectivityManager = (ConnectivityManager) context                    .getSystemService(Context.CONNECTIVITY_SERVICE);            NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();            if (mNetworkInfo != null) {                return mNetworkInfo.isAvailable();            }        }        return false;    }    ///////////////////////////////////////// 如果没有网络，则弹出网络设置对话框    public void checkNetwork(final Activity activity) {        if (!isNetworkConnected(activity)) {            TextView msg = new TextView(activity);            msg.setText("当前没有可以使用的网络，请设置网络！");            AlertDialog.Builder builder = new AlertDialog.Builder(activity);            builder.setTitle("网络状态提示")                    .setView(msg)                    .setPositiveButton("确定",                            new DialogInterface.OnClickListener() {                                public void onClick(DialogInterface dialog,                                                    int whichButton) {                                    // 跳转到设置界面                                    activity.startActivityForResult(new Intent(                                                    Settings.ACTION_WIRELESS_SETTINGS),                                            0);                                }                            }).setNegativeButton("取消", null).create().show();        }        return ;    }}