Android 檢查網路是否連線中

大家好，我是奶綠茶
如何在 Android 檢查網路是否連線，
可以使用以下程式判斷：

public static boolean isNetworkAvailable( Context context ) {
  ConnectivityManager cm = (ConnectivityManager) context
    .getApplicationContext().getSystemService(
      Context.CONNECTIVITY_SERVICE);
  if (cm == null) {
   return false;
  } else {
   NetworkInfo[] infos = cm.getAllNetworkInfo();   
   if (infos != null) {    
    for (NetworkInfo networkInfo : infos) {
     if(networkInfo.getState() == NetworkInfo.State.CONNECTED){
      return true;
     }
    }    
   }
  }
  return false;
 }

但這樣就只能限自行呼叫，如果想要用偵聽的話，可以寫一個 BroadcastReceiver,
同時在 intentFilter 加上 action android:name="android.net.conn.CONNECTIVITY_CHANGE"

public class ConnectionChangeReceiver extends BroadcastReceiver
{
@Override
public void onReceive( Context context, Intent intent ) {
boolean isNetworkAvailable = isNetworkAvailable(context);
Toast.makeText(context, "isNetworkAvailable:"+isNetworkAvailable, Toast.LENGTH_LONG).show();
}
public static boolean isNetworkAvailable( Context context ) {
  ConnectivityManager cm = (ConnectivityManager) context
    .getApplicationContext().getSystemService(
      Context.CONNECTIVITY_SERVICE);
  if (cm == null) {
   return false;
  } else {
   NetworkInfo[] infos = cm.getAllNetworkInfo();   
   if (infos != null) {    
    for (NetworkInfo networkInfo : infos) {
     if(networkInfo.getState() == NetworkInfo.State.CONNECTED){
      return true;
     }
    }    
   }
  }
  return false;
 }
}
// 在 Manifest.xml 加上
 <receiver 
            android:name="milkmidi.demo.networkstate.ConnectionChangeReceiver"
           android:label="NetworkConnection">
     <intent-filter>
       <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
     </intent-filter>
  </receiver> 

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