网络请求与Fragment的使用

ackage com.ljn.myapplication.Utils;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.ConnectivityManager;import android.net.NetworkInfo;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.util.EntityUtils;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.net.URLConnection;/** * Created by HP on 2017/11/4. */public class Utils {    public static String getNetString(String str){        try {            URL url=new URL(str);            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();            int responseCode = urlConnection.getResponseCode();            if (responseCode==200){                InputStream is = urlConnection.getInputStream();                BufferedReader br=new BufferedReader(new InputStreamReader(is));                StringBuilder sb=new StringBuilder();                String line=null;                while ((line=br.readLine())!=null){                    sb.append(line);                }                return sb.toString();            }        } catch (MalformedURLException e) {            e.printStackTrace();        }catch (IOException e) {            e.printStackTrace();        }        return null;    }    public static Bitmap getNetBitmap(String str){        try {            URL url=new URL(str);            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();            int responseCode = urlConnection.getResponseCode();            if (responseCode==200){                InputStream is = urlConnection.getInputStream();                Bitmap bitmap = BitmapFactory.decodeStream(is);                return bitmap;            }        } catch (MalformedURLException e) {            e.printStackTrace();        }catch (IOException e) {            e.printStackTrace();        }        return null;    }    public static String getJsonByHttpClientGet(String jsonUrl) {        //获取httpclient对象        DefaultHttpClient defaultHttpClient = new DefaultHttpClient();        //准备一个get请求//        HttpGet httpGet = new HttpGet(jsonUrl);        HttpPost httpPost = new HttpPost(jsonUrl);        try {            //得到服务器返回的数据;            HttpResponse response = defaultHttpClient.execute(httpPost);            //得到状态码            int statusCode = response.getStatusLine().getStatusCode();            if(statusCode ==200){                //entiry 里面封装的数据;                HttpEntity entity = response.getEntity();                //这个result就是json字符串，剩下的就是解析工作了；                //String result = EntityUtils.toString(entity);                return EntityUtils.toString(entity);            }        } catch (IOException e) {            e.printStackTrace();        }        return null;    }    /**     * 返回值 -1：没有网络  1：WIFI网络   2：net网络     //工具类 判断网络     */    public static int getNetype(Context context) {        int netType = -1;        ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();        if (networkInfo == null) {            return netType;        }        int nType = networkInfo.getType();        if (nType == ConnectivityManager.TYPE_MOBILE) {            netType = 2;        } else if (nType == ConnectivityManager.TYPE_WIFI) {            netType = 1;        }        return netType;    }
}
package com.ljn.myapplication;import android.support.annotation.IdRes;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentActivity;import android.support.v4.app.FragmentManager;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.RadioGroup;import android.widget.Toast;import com.ljn.myapplication.Fragment.MainFragment1;import com.ljn.myapplication.Fragment.MainFragment2;import com.ljn.myapplication.Fragment.MainFragment3;import com.ljn.myapplication.Fragment.MainFragment4;import com.ljn.myapplication.Utils.Utils;import java.net.JarURLConnection;import java.util.ArrayList;import java.util.List;import static android.R.id.list;public class MainActivity extends FragmentActivity {//private List<Fragment> list=new ArrayList<Fragment>();    private RadioGroup rg;    private FragmentManager manager;    private MainFragment1 fragment1;    private MainFragment2 fragment2;    private MainFragment3 fragment3;    private MainFragment4 fragment4;    @Override    protected void onResume() {        super.onResume();        int netype = Utils.getNetype(MainActivity.this);        if (netype == -1) {            Toast.makeText(this, "当前网络异常，请做联网操作！", Toast.LENGTH_SHORT).show();        } else if (netype == 1) {            Toast.makeText(this, "当前网络正常，正在使用WiFi网络", Toast.LENGTH_SHORT).show();        } else if (netype == 0) {            Toast.makeText(this, "当前网络正常，正在使用运营商网络(3G/4G),请注意流量的使用", Toast.LENGTH_SHORT).show();        }    }    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        rg = findViewById(R.id.main_rg);        //initData();        manager = getSupportFragmentManager();        fragment1 = new MainFragment1();        manager.beginTransaction().add(R.id.main_fl,fragment1).commit();        rg.setOnCheckedChangeListener(new Myoccl());    }    /*private void initData() {        list.add(new MainFragment1());        list.add(new MainFragment2());        list.add(new MainFragment3());        list.add(new MainFragment4());    }*/    private class Myoccl implements RadioGroup.OnCheckedChangeListener {        @Override        public void onCheckedChanged(RadioGroup radioGroup, @IdRes int i) {            hideFragments();            switch (i){                case R.id.main_rb1:                   // manager.beginTransaction().replace(R.id.main_fl,list.get(0)).commit();                    manager.beginTransaction().show(fragment1).commit();                    break;                case R.id.main_rb2:                   // manager.beginTransaction().replace(R.id.main_fl,list.get(1)).commit();                    if (fragment2==null){                        fragment2 = new MainFragment2();                        manager.beginTransaction().add(R.id.main_fl,fragment2).commit();                    }else{                        manager.beginTransaction().show(fragment2).commit();                    }                    break;                case R.id.main_rb3:                  //  manager.beginTransaction().replace(R.id.main_fl,list.get(2)).commit();                    if (fragment3==null){                        fragment3 = new MainFragment3();                        manager.beginTransaction().add(R.id.main_fl,fragment3).commit();                    }else{                        manager.beginTransaction().show(fragment3).commit();                    }                    break;                case R.id.main_rb4:                   // manager.beginTransaction().replace(R.id.main_fl,list.get(3)).commit();                    if (fragment4==null){                        fragment4 = new MainFragment4();                        manager.beginTransaction().add(R.id.main_fl,fragment4).commit();                    }else{                        manager.beginTransaction().show(fragment4).commit();                    }                    break;            }        }    }    private void hideFragments(){    if (fragment1!=null&&fragment1.isAdded()){        manager.beginTransaction().hide(fragment1).commit();    }    if (fragment2!=null&&fragment2.isAdded()){        manager.beginTransaction().hide(fragment2).commit();    }    if (fragment3!=null&&fragment3.isAdded()){        manager.beginTransaction().hide(fragment3).commit();    }    if (fragment4!=null&&fragment4.isAdded()){        manager.beginTransaction().hide(fragment4).commit();    }        //manager.beginTransaction().commit();    }}

package com.ljn.myapplication.Fragment;import android.graphics.Bitmap;import android.os.AsyncTask;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.ListAdapter;import android.widget.ListView;import android.widget.TextView;import com.google.gson.Gson;import com.ljn.myapplication.Bean.TextBean;import com.ljn.myapplication.R;import com.ljn.myapplication.Utils.Utils;import java.util.ArrayList;import java.util.List;/** * Created by HP on 2017/11/4. */public class MainFragment1 extends Fragment {    private ListView lv;    private String NetString="https://api.tianapi.com/wxnew/?key=8d6e3228d25298f13af4fc40ce6c9679&num=10";    private List<TextBean.NewslistBean> list=new ArrayList<TextBean.NewslistBean>();    private MyAdapter adapter;    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        View view = inflater.inflate(R.layout.mainfragment1, container, false);        lv = view.findViewById(R.id.child1_lv);        return view;    }    @Override    public void onActivityCreated(@Nullable Bundle savedInstanceState) {        super.onActivityCreated(savedInstanceState);        new MyAsyncTask().execute(NetString);        adapter = new MyAdapter();        lv.setAdapter(adapter);        adapter.notifyDataSetChanged();    }    private class MyAsyncTask extends AsyncTask<String,Void,String>{        @Override        protected String doInBackground(String... strings) {            return Utils.getNetString(strings[0]);        }        @Override        protected void onPostExecute(String s) {            super.onPostExecute(s);            Gson gson=new Gson();            TextBean json = gson.fromJson(s, TextBean.class);            List<TextBean.NewslistBean> newslist = json.getNewslist();            list.addAll(newslist);        }    }    private class MyAdapter extends BaseAdapter {        private ViewHolder vh;        private TextView ctime;        private TextView title;        private TextView description;        private ImageView img;        @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){                vh = new MainFragment1.ViewHolder();                view = View.inflate(getActivity(), R.layout.item, null);                view.setTag(vh);            }else{                 vh = (ViewHolder) view.getTag();            }            vh.ctime = view.findViewById(R.id.item_ctime);            vh.title = view.findViewById(R.id.item_title);            vh.description = view.findViewById(R.id.item_description);            vh.img = view.findViewById(R.id.item_img);            vh.ctime.setText(list.get(i).getCtime());            vh.title.setText(list.get(i).getTitle());            vh.description.setText(list.get(i).getDescription());            new MyBitmap(vh.img).execute(list.get(i).getPicUrl());            return view;        }        private class MyBitmap extends AsyncTask<String,Void,Bitmap>{            private ImageView img;            public MyBitmap(ImageView img) {                this.img=img;            }            @Override            protected Bitmap doInBackground(String... strings) {                return Utils.getNetBitmap(strings[0]);            }            @Override            protected void onPostExecute(Bitmap bitmap) {                super.onPostExecute(bitmap);                img.setImageBitmap(bitmap);            }        }    }    class ViewHolder{        TextView ctime;        TextView title;        TextView description;        ImageView img;    }}