检查 android (eclipse) 上的互联网连接

Question

我需要这个算法在 android Eclipse 编程中的代码：

If internet connection = connect then open program 
else show error_activity.xml

Answer 1

创建一个类ConnectionDetector并将以下代码放入该类中：

private Context _context;

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

public boolean isConnectingToInternet() {
    ConnectivityManager connectivity = (ConnectivityManager) _context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity != null) {
        NetworkInfo[] info = connectivity.getAllNetworkInfo();
        if (info != null)
            for (int i = 0; i < info.length; i++)
                if (info[i].getState() == NetworkInfo.State.CONNECTED) {
                    return true;
                }

    }
    return false;
}

// 现在无论你想在哪里检查互联网，只需创建一个此类的对象并调用它的方法，如下所示：

// 在你的活动中定义全局变量：

Boolean _isInternetPresent = false;
ConnectionDetector _cd;

//在创建时

    _cd = new ConnectionDetector(getApplicationContext());
    _isInternetPresent = _cd.isConnectingToInternet();

然后像这样检查：

         if (_isInternetPresent) {
            // do you work here
            } else {
                    // no internet,please try again.

           }

因为你是一个新手，我给你完整的代码。请试着理解每一步，这个代码是如何工作的。

Answer 2

试试这个检查互联网连接..

public void checkNetwork() {
        ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();

        if (networkInfo != null && networkInfo.isConnected()) {
            //true : your code
        } else {
            //false : your code
            Log.v("Network Error", "No network connection available.");
        }
    }

Answer 3

创建检测连接的类非常简单。

public class ConnectionDetector {

private Context _context;

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

public boolean isConnectingToInternet(){
    ConnectivityManager connectivity = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
      if (connectivity != null) 
      {
          NetworkInfo[] info = connectivity.getAllNetworkInfo();
          if (info != null) 
              for (int i = 0; i < info.length; i++) 
                  if (info[i].getState() == NetworkInfo.State.CONNECTED)
                  {
                      return true;
                  }

      }
      return false;
}

}

并检查设备是否连接到互联网。

在使用之前初始化 cd。 isInternetPresent = cd.isConnectingToInternet();

            // check for Internet status
        if (isInternetPresent) {
            // Internet Connection is Present
            // make HTTP requests
            showAlertDialog(AndroidDetectInternetConnectionActivity.this, "Internet Connection",
                    "You have internet connection", true);
        } else {
            // Internet connection is not present
            // Ask user to connect to Internet
            showAlertDialog(AndroidDetectInternetConnectionActivity.this, "No Internet Connection",
                    "You don't have internet connection.", false);
        }

Answer 4

步骤 1. 创建 ConnectionDetector.java

package com.YOURPACKAGE.YOURAPP;

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

public class ConnectionDetector {

private Context _context;

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

public boolean checkInternetConn() {
    ConnectivityManager connectivity = (ConnectivityManager) _context
            .getSystemService(Context.CONNECTIVITY_SERVICE);
    if (connectivity != null) {
        NetworkInfo info = connectivity.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

        if(info == null){
            connectivity.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
        }

        if(info == null){
            connectivity.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET);
        }

        if (info != null) {
            if (info.isConnected()) {
                return true;
            }
        }
    }
    return false;
}
}

第 2 步。在您的 Activity 中实施连接检测器

public class YOURACTIVITY extends Activity {

    ConnectionDetector cd;

    private void methodThatNeedsTheInternet() {

        Boolean isConnectionExist = false;
        isConnectionExist = cd.checkInternetConn();

        // check for Internet status before proceeding
        if (!isConnectionExist) {
            //no internet, show alert or something
            return;
        }

        //internet works, perform method that needs it
    }

}