如何在 Android 中测试互联网连接是否有效

6
我正在使用这种方法来ping谷歌服务器,以便检查活动的网络连接,但我发现它在某些设备上无法工作。
我尝试使用其他方法,如HttpURLConnection和URLConnection,但它们即使在连接时也会返回false。
有什么想法或解决方案可以在所有设备上运行。提前感谢您的回答。我将按顺序发布我已经尝试过的内容。
方法1:
public static Boolean isOnline() {
    try {
        Process p1 = java.lang.Runtime.getRuntime().exec("ping -c 1 8.8.8.8");
        int returnVal = p1.waitFor();
        return (returnVal == 0);
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return false;
}

我已经尝试过本地和谷歌服务器,并且产生了完美的结果。问题是它不能在所有设备上运行。

方法2:

public boolean isConnected() {
    boolean connectivity;
    try {
        URL url = new URL("www.google.com");
        URLConnection conn = url.openConnection();
        conn.setConnectTimeout(5000);
        conn.connect();
        connectivity = true;
    } catch (Exception e) {
        connectivity = false;
    }
    return connectivity;
}

无论我的连接是否活动,这个方法总是返回false。 方法三:
public static boolean isInternetReachable() {
    try {
        //make a URL to a known source
        URL url = new URL("http://www.google.co.ke");

        //open a connection to that source
        HttpURLConnection urlConnect = (HttpURLConnection) url.openConnection();

        Object objData = urlConnect.getContent();

    } catch (Exception e) {
        e.printStackTrace();
        return false;
    }

    return true;
}

与这个相同。假值.

上一个是这个类,但它也在做相同的事情:

class TestInternet extends AsyncTask<Void, Void, Boolean> {
    @Override
    protected Boolean doInBackground(Void... params) {
        try {
            URL url = new URL("http://www.google.com");
            HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
            urlc.setConnectTimeout(3000);
            urlc.connect();
            if (urlc.getResponseCode() == 200) {
                connected = true;
                return connected;
            }
        } catch (MalformedURLException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            connected = false;
            return connected;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            connected = false;
            return connected;
        }
        return connected;
    }

    @Override
    protected void onPostExecute(Boolean result) {
        if (!result) { // code if not connected
            AlertDialog.Builder builder = new AlertDialog.Builder(CtgActivity.this);
            builder.setMessage("An internet connection is required.");
            builder.setCancelable(false);

            builder.setPositiveButton(
                    "TRY AGAIN",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            dialog.cancel();
                            new TestInternet().execute();
                        }
                    });


            AlertDialog alert11 = builder.create();
            alert11.show();
        } else { // code if connected
            Toast.makeText(CtgActivity.this,"Yes",Toast.LENGTH_LONG).show();
        }
    }

    @Override
    protected void onPreExecute() {
        Toast.makeText(getBaseContext(),"Checking for internet",Toast.LENGTH_LONG).show();
        super.onPreExecute();
    }
}

我在浏览Stack Overflow寻找任何有关的内容,但所有的都与这些问题有关。请告诉我是否我做错了什么或建议更好的解决方法。这是我项目的最后一步。

5个回答

3

请按照以下代码检查互联网是否可用以及是否处于活动状态。

   //I have taken dummy icon from server, so it may be removed in future. So you can place one small icon on server and then access your own URL.

1. 在 manifest 文件中指定权限,同时确保处理 marshmallow 运行时权限。由于我不会在这里展示运行时权限,请注意。

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

2. 检查网络连接是否可用并状态为活动或非活动。

        public class InternetDemo extends Activity
        {
            @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                checkInternetAvailibility();
            }

            public void checkInternetAvailibility()
            {
                if(isInternetAvailable())
                {
                    new IsInternetActive().execute();
                }
                else {
                    Toast.makeText(getApplicationContext(), "Internet Not Connected", Toast.LENGTH_LONG).show();
                }
            }

            public boolean isInternetAvailable() {
                try {
                    ConnectivityManager connectivityManager
                            = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
                    NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
                    return activeNetworkInfo != null && activeNetworkInfo.isConnected();
                } catch (Exception e) {

                    Log.e("isInternetAvailable:",e.toString());
                    return false;
                }
            }

            class IsInternetActive extends AsyncTask<Void, Void, String>
            {
                InputStream is = null;
                String json = "Fail";

                @Override
                protected String doInBackground(Void... params) {
                    try {
                        URL strUrl = new URL("http://icons.iconarchive.com/icons/designbolts/handstitch-social/24/Android-icon.png");
                        //Here I have taken one android small icon from server, you can put your own icon on server and access your URL, otherwise icon may removed from another server.

                        URLConnection connection = strUrl.openConnection();
                        connection.setDoOutput(true);
                        is =  connection.getInputStream();
                        json = "Success";

                    } catch (Exception e) {
                        e.printStackTrace();
                        json = "Fail";
                    }
                    return json;

                }

                @Override
                protected void onPostExecute(String result) {
                    if (result != null)
                    {
                       if(result.equals("Fail"))
                       {
                           Toast.makeText(getApplicationContext(), "Internet Not Active", Toast.LENGTH_LONG).show();
                       }
                       else
                       {
                           Toast.makeText(getApplicationContext(), "Internet Active " + result, Toast.LENGTH_LONG).show();
                       }
                    }
                    else
                    {
                        Toast.makeText(getApplicationContext(), "Internet Not Active", Toast.LENGTH_LONG).show();
                    }
                }

                @Override
                protected void onPreExecute() {
                    Toast.makeText(getBaseContext(),"Validating Internet",Toast.LENGTH_LONG).show();
                    super.onPreExecute();
                }
            }
        }

1
您是真正的MVP。它完美地按照我的要求工作。 - Kennedy Kambo
当连接上但没有数据时,验证需要很长时间,我该如何减少响应时间?如果可能的话。 - Kennedy Kambo
在代码中我提到了,您需要放置自己的非常小的图像或者在URL中发送一些文本,这样可以减少响应时间并且轻松获取响应。 - Vickyexpert
为什么我会收到FileNotFoundException异常? - M Umer

1
步骤1:创建连接检测器。
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

import java.net.HttpURLConnection;
import java.net.URL;


    /**
     * Created by Ramana Tech Architect 2/24/2018.
     */

    public class ConnectionDetector {

    private Context _context;

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

    public boolean isConnectingToInternet() {
        ConnectivityManager cm = (ConnectivityManager) this._context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        if (activeNetwork != null) { // connected to the internet
                try {
                    URL url = new URL("http://www.google.com");
                    HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
                    urlc.setConnectTimeout(300);
                    urlc.connect();
                    if (urlc.getResponseCode() == 200) {
                        return true;
                    }
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    return false;
                }
        }
        return false;
    }
}

步骤2:使用ConnectionDetector。
private ConnectionDetector cd;

        cd = new ConnectionDetector(getApplicationContext());

        if (cd.isConnectingToInternet()) {
             /// block of code 
          }

测试输出: 输入图像描述

我连接了Wi-Fi和移动网络,所以日志中的输出两次为true。 我断开了Wi-Fi,所以第三行为false。


等一下。我不是在检查网络是否连接。我是在检查连接是否活动。 - Kennedy Kambo
我希望你得到了准确的解决方案。 - Ramana V V K
我已经尝试过了,但它仍然返回false。我尝试将超时时间增加到三秒,并将响应时间增加到两秒,但仍然返回false。 - Kennedy Kambo
是的,即使有<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />也是这样。 - Kennedy Kambo
是的...而且我点赞的答案完美地运作了>你的似乎可以工作,只是我不知道我做错了什么。 - Kennedy Kambo
显示剩余8条评论

0

0
在你的包中创建一个名为ProjectUtils的类:
不要忘记在你的清单文件中添加以下内容: <uses-permission android:name="android.permission.INTERNET" /> ProjectUtils.java :
public class ProjectUtils {

    Context context;

    public ProjectUtils(Context context) {
        this.context = context;
    }



    public boolean haveNetworkConnection() {

        boolean haveConnectedWifi = false;
        boolean haveConnectedMobile = false;

        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo[] netInfo = cm.getAllNetworkInfo();
        for (NetworkInfo ni : netInfo) {
            if (ni.getTypeName().equalsIgnoreCase("WIFI"))
                if (ni.isConnected())
                    haveConnectedWifi = true;
            if (ni.getTypeName().equalsIgnoreCase("MOBILE"))
                if (ni.isConnected())
                    haveConnectedMobile = true;
        }
        return haveConnectedWifi || haveConnectedMobile;
    }

    public void showtoast(String text) {
        Toast.makeText(context, text, Toast.LENGTH_SHORT).show();
    }

}

在你的Activity中:

  ProjectUtils utils;

     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);

        utils = new ProjectUtils(this);

             if (utils.haveNetworkConnection()) {
                   jsonRequestCall();
                } else {
                     utils.showtoast("Internet Connection Not Available");
                }

    }

如果您想在几秒钟内每次检查互联网连接,则必须使用BroadcastReceiver。
参考:

1
这个检查手机是否连接到网络。我想要的是检查连接的网络是否正常工作。比如说,我能否与服务器通信?这就是我想要的。不过有一件事,jsonRequestCall方法是什么? - Kennedy Kambo
jsonRequestCall(); 只是一个方法调用,你也可以在那里显示 Toast。当这个 Activity 第一次启动时,我的代码会检查互联网,如果有互联网,它将调用方法,否则会显示 "互联网不可用" 的 Toast。@Thekamble - Abhishek kumar
那么这不是我想要的。有时候你连接到网络,但没有加载数据,所以无法与服务器通信。这就是我想要检查的。 - Kennedy Kambo
你想像今天的通讯应用程序一样检查每次互联网连接吗?@Thekamble - Abhishek kumar
是的,但对于我的情况,并不总是如此。就像链接中的应用程序一样,只需要一次检查即可,例如:https://www.apk4fun.com/link/77870/a/。只需要进行一次检查,以便我可以根据结果决定加载哪种布局。 - Kennedy Kambo
显示剩余2条评论

0

我也没有尝试过,但我找到了这个:

public static boolean isInternetAvailable() {
    Boolean isConnection = false;
    int connectTimeout = 5000; // in ms
    int readTimeout = 5000; // in ms
    String ip204 = "http://clients3.google.com/generate_204";

    try {
        URL url = new URL(ip204);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setConnectTimeout(connectTimeout);
        conn.setReadTimeout(readTimeout);
        conn.setRequestMethod("HEAD");
        InputStream in = conn.getInputStream();
        int status = conn.getResponseCode();
        in.close();
        conn.disconnect();
        if (status == HttpURLConnection.HTTP_NO_CONTENT) {
            isConnection = true;
        }
    } catch (Exception e) {
        isConnection = false;
    }
}

但是这个方法必须在与主线程不同的线程中,所以它是异步的 :/

我没有尝试过这个,但我在网上找到了一个使用NetworkCallback的代码:

private void listenNetworkViaConnectivityManager(final Context context) {
  ConnectivityManager cm = (ConnectivityManager) context
      .getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkRequest request = new NetworkRequest.Builder()
      .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
      .build();
  cm.registerNetworkCallback(request, new ConnectivityManager.NetworkCallback() {
    @Override
    public void onAvailable(Network network) {
      // do what you want
    }
  });
}

但可能与ConnectivityManager相同...而且它也使用回调,因此是异步的,不能返回同步值true/false,我想:/也许,如果这样可以按照您的要求工作,您可以使用服务或类似服务的东西每隔一段时间检查连接,然后设置一个标志变量,一个静态全局变量为true,如果有互联网连接,则为false。要检查是否存在或不存在,只需检查此标志。

我没有尝试过,我认为这是一种非常糟糕的方法,但我没有找到其他解决方案,所以...也许您可以使用SNTP客户端代替ping函数(显然将超时设置为非常小的值)。

public static Date getCurrentDateFromSNTP() {
        try {
            SntpClient client = new SntpClient();
            if (client.requestTime(SntpClient.NTP_SERVER, SntpClient.NTP_TIMEOUT)) {
                long now = client.getNtpTime() + SystemClock.elapsedRealtime() - client.getNtpTimeReference();
                return new Date(now);
            }
        } catch (Exception e) {
            EMaxLogger.onException(TAG, e);
        }
        return new Date();
    }

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.emax.it.lib_commons.modules.networking.clients;

import android.os.AsyncTask;
import android.os.SystemClock;
import android.text.TextUtils;
import android.util.Log;

import com.emax.it.lib_commons.modules.loggers.EMaxLogger;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.concurrent.ExecutionException;

/**
 * {@hide}
 *
 * Simple SNTP client class for retrieving network time.
 *
 * Sample usage:
 * <pre>SntpClient client = new SntpClient();
 * if (client.requestTime("time.foo.com")) {
 *     long now = client.getNtpTime() + SystemClock.elapsedRealtime() -
 * client.getNtpTimeReference();
 * }
 * </pre>
 */
public class SntpClient {

    private static final String TAG = SntpClient.class.getSimpleName();
    // Ntp
    public static final String NTP_SERVER = "time.google.com";
    public static final int NTP_TIMEOUT = 2 * 1000; // 2 secondi il timeout
    // Time Offset Data
    private static final int REFERENCE_TIME_OFFSET = 16;
    private static final int ORIGINATE_TIME_OFFSET = 24;
    private static final int RECEIVE_TIME_OFFSET = 32;
    private static final int TRANSMIT_TIME_OFFSET = 40;
    // NTP Data
    private static final int NTP_PACKET_SIZE = 48;
    private static final int NTP_PORT = 123;
    private static final int NTP_MODE_CLIENT = 3;
    private static final int NTP_VERSION = 3;
    // Number of seconds between Jan 1, 1900 and Jan 1, 1970
    // 70 years plus 17 leap days
    private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L;
    // system time computed from NTP server response
    private long mNtpTime;
    // value of SystemClock.elapsedRealtime() corresponding to mNtpTime
    private long mNtpTimeReference;
    // round trip time in milliseconds
    private long mRoundTripTime;

    /**
     * Returns the time computed from the NTP transaction.
     *
     * @return time value computed from NTP server response.
     */
    public long getNtpTime() {
        return mNtpTime;
    }

    public void setNtpTime(long ntpTime){
        mNtpTime = ntpTime;
    }

    /**
     * Returns the reference clock value (value of SystemClock.elapsedRealtime())
     * corresponding to the NTP time.
     *
     * @return reference clock corresponding to the NTP time.
     */
    public long getNtpTimeReference() {
        return mNtpTimeReference;
    }

    public void setNtpTimeReference(long ntpTimeReference){
        mNtpTimeReference = ntpTimeReference;
    }

    /**
     * Returns the round trip time of the NTP transaction
     *
     * @return round trip time in milliseconds.
     */
    public long getRoundTripTime() {
        return mRoundTripTime;
    }

    public void setRoundTripTime(long roundTripTime){
        mRoundTripTime = roundTripTime;
    }

    /**
     * Sends an SNTP request to the given host and processes the response.
     *
     * @param host    host name of the server.
     * @param timeout network timeout in milliseconds.
     * @return true if the transaction was successful.
     */
    public boolean requestTime(String host, int timeout) {
        try {
            return new RequestTimeTask(this, host, timeout).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR).get();
        } catch (InterruptedException iE) {
            EMaxLogger.onException(TAG, iE);
        } catch (ExecutionException eE) {
            EMaxLogger.onException(TAG, eE);
        }
        return false;
    }

    /**
     * Reads an unsigned 32 bit big endian number from the given offset in the buffer.
     */
    private long read32(byte[] buffer, int offset) {
        byte b0 = buffer[offset];
        byte b1 = buffer[offset + 1];
        byte b2 = buffer[offset + 2];
        byte b3 = buffer[offset + 3];

        // convert signed bytes to unsigned values
        int i0 = ((b0 & 0x80) == 0x80 ? (b0 & 0x7F) + 0x80 : b0);
        int i1 = ((b1 & 0x80) == 0x80 ? (b1 & 0x7F) + 0x80 : b1);
        int i2 = ((b2 & 0x80) == 0x80 ? (b2 & 0x7F) + 0x80 : b2);
        int i3 = ((b3 & 0x80) == 0x80 ? (b3 & 0x7F) + 0x80 : b3);

        return ((long) i0 << 24) + ((long) i1 << 16) + ((long) i2 << 8) + (long) i3;
    }

    /**
     * Reads the NTP time stamp at the given offset in the buffer and returns
     * it as a system time (milliseconds since January 1, 1970).
     */
    private long readTimeStamp(byte[] buffer, int offset) {
        long seconds = read32(buffer, offset);
        long fraction = read32(buffer, offset + 4);
        return ((seconds - OFFSET_1900_TO_1970) * 1000) + ((fraction * 1000L) / 0x100000000L);
    }

    /**
     * Writes system time (milliseconds since January 1, 1970) as an NTP time stamp
     * at the given offset in the buffer.
     */
    private void writeTimeStamp(byte[] buffer, int offset, long time) {
        long seconds = time / 1000L;
        long milliseconds = time - seconds * 1000L;
        seconds += OFFSET_1900_TO_1970;

        // write seconds in big endian format
        buffer[offset++] = (byte) (seconds >> 24);
        buffer[offset++] = (byte) (seconds >> 16);
        buffer[offset++] = (byte) (seconds >> 8);
        buffer[offset++] = (byte) (seconds >> 0);

        long fraction = milliseconds * 0x100000000L / 1000L;
        // write fraction in big endian format
        buffer[offset++] = (byte) (fraction >> 24);
        buffer[offset++] = (byte) (fraction >> 16);
        buffer[offset++] = (byte) (fraction >> 8);
        // low order bits should be random data
        buffer[offset++] = (byte) (Math.random() * 255.0);
    }

    /** Private Classes **/
    private static class RequestTimeTask extends AsyncTask<Void, Void, Boolean> {

        private SntpClient mOuter;
        private String mHost;
        private int mTimeout;

        RequestTimeTask(SntpClient outer, String host, int timeout){
            mOuter = outer;
            mHost = host;
            mTimeout = timeout;
        }

        /** Override AsyncTask Methods **/
        @Override
        protected Boolean doInBackground(Void... voids) {
            try (DatagramSocket socket = new DatagramSocket()) {
                socket.setSoTimeout(mTimeout);
                InetAddress address = InetAddress.getByName(mHost);
                byte[] buffer = new byte[NTP_PACKET_SIZE];
                DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT);

                // set mode = 3 (client) and version = 3
                // mode is in low 3 bits of first byte
                // version is in bits 3-5 of first byte
                buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION << 3);

                // get current time and write it to the request packet
                long requestTime = System.currentTimeMillis();
                long requestTicks = SystemClock.elapsedRealtime();
                mOuter.writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET, requestTime);

                socket.send(request);

                // read the response
                DatagramPacket response = new DatagramPacket(buffer, buffer.length);
                socket.receive(response);
                long responseTicks = SystemClock.elapsedRealtime();
                long responseTime = requestTime + (responseTicks - requestTicks);

                // extract the results
                long originateTime = mOuter.readTimeStamp(buffer, ORIGINATE_TIME_OFFSET);
                long receiveTime = mOuter.readTimeStamp(buffer, RECEIVE_TIME_OFFSET);
                long transmitTime = mOuter.readTimeStamp(buffer, TRANSMIT_TIME_OFFSET);
                long roundTripTime = responseTicks - requestTicks - (transmitTime - receiveTime);
                // receiveTime = originateTime + transit + skew
                // responseTime = transmitTime + transit - skew
                // clockOffset = ((receiveTime - originateTime) + (transmitTime - responseTime))/2
                //             = ((originateTime + transit + skew - originateTime) +
                //                (transmitTime - (transmitTime + transit - skew)))/2
                //             = ((transit + skew) + (transmitTime - transmitTime - transit + skew))/2
                //             = (transit + skew - transit + skew)/2
                //             = (2 * skew)/2 = skew
                long clockOffset = ((receiveTime - originateTime) + (transmitTime - responseTime)) / 2;
                // if (false) Log.d(TAG, "round trip: " + roundTripTime + " ms");
                // if (false) Log.d(TAG, "clock offset: " + clockOffset + " ms");

                // save our results - use the times on this side of the network latency
                // (response rather than request time)
                mOuter.setNtpTime(responseTime + clockOffset);
                mOuter.setNtpTimeReference(responseTicks);
                mOuter.setRoundTripTime(roundTripTime);
                return true;
            } catch (Exception e) {
                if(TextUtils.isEmpty(e.getMessage())){
                    Log.e(TAG, String.format("No Message for %1$s", e.getClass().getSimpleName()));
                } else {
                    Log.e(TAG, e.getMessage());
                }
                e.printStackTrace();
                return false;
            }
        }

    }

}

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