检查Android网络连接状态

最新推荐文章于 2025-07-26 12:11:54 发布

转载最新推荐文章于 2025-07-26 12:11:54 发布 · 302 阅读

本文介绍如何在Android应用中实现网络连接检测功能。通过创建ConnectionDetector类并使用Android系统的ConnectivityManager来判断设备是否连接到互联网。此外，还提供了一个示例展示如何在应用启动时根据网络连接情况采取不同操作。

为了访问网络我们需要 INTERNET 权限
为了检查网络状态我们需要 ACCESS_NETWORK_STATE 权限

AndroidManifest.xml

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

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

创建一个新的类，名为ConnectionDetector.java

package com.wise.siyuan.net;

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 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;
    }
}

当你需要在你的应用中检查网络状态时调用isConnectingToInternet()函数，它会返回true或false。

ConnectionDetector cd = new ConnectionDetector(getApplicationContext());

Boolean isInternetPresent = cd.isConnectingToInternet(); // true or false

==============================================================================

if (isInternetPresent) {
start();
  } else {
   //opendatebase();
   showDialog("未接入互联网,请设置网络");
  }

==============================================================================

  private void showDialog(String mess) {
   new AlertDialog.Builder(this).setTitle("信息").setMessage(mess)
     .setNegativeButton("确定", new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int which) {
       dialog.dismiss();
       int currentVersion = android.os.Build.VERSION.SDK_INT;
       if (currentVersion > android.os.Build.VERSION_CODES.ECLAIR_MR1) {
        Intent startMain = new Intent(Intent.ACTION_MAIN);
        startMain.addCategory(Intent.CATEGORY_HOME);
        startMain.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(startMain);
        System.exit(0);
       } else {// android2.1
        ActivityManager am = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
        am.restartPackage(getPackageName());
       }
      }
     }).show();
  }