Java 检查android（eclipse）上的internet连接

我需要android Eclipse编程中此算法的代码：

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

---

尝试此操作以检查internet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.");
        }
    }

---

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;
}

//立即创建

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

检查如下：

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

           }

---

由于您是一名新生，我将为您提供完整的代码。请尝试了解每一步，以及此代码的工作原理。

非常简单，只需创建检测连接的类即可

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;
}

---

第1步。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。在活动中实施连接检测器

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
    }

}

---

在提问之前，请进行最少量的研究。另外，StackOverflow并不是为了请求人们为您编写代码；这是为了帮你写代码。对所有的选民来说，我要求删除，他是个新手。

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;
}
}

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
    }

}