A summary of Android network judgment Knowledge _android

Android to determine if the current network is available

Application scenario: Implementation to determine whether the current network is available

There are currently available networks, as shown below:

There are currently no networks available, as shown in the following figure:

Implementation steps:

1. Get Connectivitymanager Object

Context context = Activity.getapplicationcontext ();
Get all connection management objects on the phone (including the management of connections to wi-fi,net)
connectivitymanager Connectivitymanager = (Connectivitymanager) Context.getsystemservice (Context.connectivity_service);

2. Get Networkinfo Object

Get Networkinfo object
networkinfo[] Networkinfo = Connectivitymanager.getallnetworkinfo ();

3, determine whether the current network state is connected state

if (networkinfo[i].getstate () = = NetworkInfo.State.CONNECTED)
{return
   true;
}

4. Add access to current network state permissions in Androidmanifest.xml

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

The code is as follows:

public class Classtestdemoactivity extends activity {@Override public void onCreate (Bundle savedinstancestate) {
    Super.oncreate (savedinstancestate);
    Setcontentview (R.layout.main); if (isnetworkavailable (classtestdemoactivity.this)) {Toast.maketext (Getapplicationcontext (), "There is currently a network available!")
    ", Toast.length_long). Show (); else {toast.maketext (getapplicationcontext), "There is no network currently available!"
    ", Toast.length_long). Show (); }/** * Check that the current network is available * * @param context * @return/public boolean isnetworkavailable (active ACTI
    Vity) {Context context = Activity.getapplicationcontext (); Get all connection management objects on the phone (including the management of connections to wi-fi,net) Connectivitymanager Connectivitymanager = (Connectivitymanager)
    Context.getsystemservice (Context.connectivity_service);
    if (Connectivitymanager = = null) {return false;
      else {//Get Networkinfo object networkinfo[] Networkinfo = Connectivitymanager.getallnetworkinfo (); if (Networkinfo!= null && networkinfo.length > 0 {for (int i = 0; i < networkinfo.length; i++)
          {System.out.println (i + "= = = State = =" + networkinfo[i].getstate ());
          SYSTEM.OUT.PRINTLN (i + "= = = Type = = =" + Networkinfo[i].gettypename ()); Determines whether the current network state is a connection state if (networkinfo[i].getstate () = = NetworkInfo.State.CONNECTED) {return
          True
  }}} return false;

 }
}

The result of the console printing:

Android about determining whether an application has a network

In Android programming, there are many applications to determine whether there is a network of problems, now I would like to say about the network, the source code is as follows:

. java

 /** * Check whether the current network is available * * @param context * @return/public boolean isnetworkavailable (active activity)
    {Context context = Activity.getapplicationcontext (); Get all connection management objects on the phone (including the management of connections to wi-fi,net) Connectivitymanager Connectivitymanager = (Connectivitymanager)
    Context.getsystemservice (Context.connectivity_service);
    if (Connectivitymanager = = null) {return false;
      else {//Get Networkinfo object networkinfo[] Networkinfo = Connectivitymanager.getallnetworkinfo ();  if (networkinfo!= null && networkinfo.length > 0) {for (int i = 0; i < networkinfo.length;
          i++) {System.out.println (i + "= = = State = =" + networkinfo[i].getstate ());
          SYSTEM.OUT.PRINTLN (i + "= = = Type = = =" + Networkinfo[i].gettypename ()); Determines whether the current network state is a connection state if (networkinfo[i].getstate () = = NetworkInfo.State.CONNECTED) {return
          True
   }
        }
      }
    } return false; }

To judge this method in the OnCreate () method, the specific code is as follows:

. java

@Override
  protected void onCreate (Bundle savedinstancestate) {
    super.oncreate (savedinstancestate);  
    Setcontentview (r.layout.activity_main);
    if (isnetworkavailable (maintivity.this) {
 Toast.maketext (this, "There is currently a network available!") ", Toast.length_long). Show ();
 else{
 Toast.maketext (This, "No network currently!") ", Toast.length_long). Show ();}
 

Additionally, you need to add permissions

<!--allows applications to be networked-->
  <uses-permission android:name= "Android.permission.INTERNET"/>
   <!-- Allow applications to check network conditions-->
 <uses-permission android:name= "Android.permission.ACCESS_NETWORK_STATE" ></ Uses-permission>