网络判断 异步加载

package com.example.liangjinzi20190218;

import android.content.Context;
import android.net.ConnectivityManager;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class Util {
///创建接口
public interface CallBackA {
//写方法
void getData(String s);
}

//封装异步
public static void getAsyncTask(String url, final CallBackA backA) {

    new AsyncTask<String, Void, String>() {
        @Override
        protected String doInBackground(String... strings) {
            return httpGet(strings[0]);
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            backA.getData(s);

        }
    }.execute(url);
}


//====================================================================
/*
 * 网络判断
 * */
public static boolean isNetworkConnected(Context context) {

    if (context != null) {
        //获取连接管理器
        ConnectivityManager mConnectivityManager = (ConnectivityManager)
                context.getSystemService(Context.CONNECTIVITY_SERVICE);
        //获取网络状态
        NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();
        if (mNetworkInfo != null) {
            //判断网络是否可用
            return mNetworkInfo.isAvailable();
        }
    }
    return false;
}
public static String httpGet(String strUrl) {
    //设置url
    try {
        URL url = new URL(strUrl);
        //获取HttpURLConnection
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        //设置为get请求
        connection.setRequestMethod("GET");
        //设置连接主机超时时间
        connection.setConnectTimeout(5000);
        //设置从主机读取数据超时
        connection.setReadTimeout(5000);
        //得到数据
        InputStream stream = connection.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
        //拼接数据
        StringBuilder builder = new StringBuilder();
        String str = "";
        while ((str = reader.readLine()) != null) {
            builder.append(str);
        }
        //关闭连接
        connection.disconnect();
        //返回数据
        return builder.toString();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

}