android - 检测Android设备是否连接到互联网

这是我的课程，检查设备是否连接到Internet。

import android.app.Activity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;


public class ConnectionDetector {
    private Context _context;

    public ConnectionDetector(Context context) {
        this._context = context;
    }

    public boolean isConnectingToInternet() {
        if (networkConnectivity()) {
            try {
                HttpURLConnection urlc = (HttpURLConnection) (new URL(
                        "http://www.google.com").openConnection());
                urlc.setRequestProperty("User-Agent", "Test");
                urlc.setRequestProperty("Connection", "close");
                urlc.setConnectTimeout(3000);
                urlc.setReadTimeout(4000);
                urlc.connect();
                // networkcode2 = urlc.getResponseCode();
                return (urlc.getResponseCode() == 200);
            } catch (IOException e) {
                return (false);
            }
        } else
            return false;

    }

    private boolean networkConnectivity() {
    ConnectivityManager cm = (ConnectivityManager) _context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = cm.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected()) {
        return true;
    }
    return false;
}

}

然后我在这里叫它，但它似乎不返回真或假。没有错误，我的应用程序没有崩溃，只是没有打印出任何东西。有人知道为什么吗？

public void CheckInternet(){

   // Boolean isInternetPresent;

    ConnectionDetector cd = new ConnectionDetector(getApplicationContext());

 //   isInternetPresent = cd.isConnectingToInternet();

    if (cd.isConnectingToInternet()) {
        // Internet Connection is Present

        Log.i(TAG, "INTERNET IS GUUD");

    } else {
        // Internet connection is not present
        // Ask user to connect to Internet
        Log.i(TAG, "INTERNET IS NOOOO GUUD");

    }
}

最佳答案

创建类：

public class Utility {
    public static boolean isNetworkAvailable(Context context) {
        ConnectivityManager connectivityManager
                = (ConnectivityManager)  context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        return activeNetworkInfo != null && activeNetworkInfo.isConnected();
    }
}

然后从活动调用methode，它将返回true或false：

Utility.isNetworkAvailable(AnyActivity.this);

别忘了给android清单添加权限

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