判断网络是否可用

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(), "当前有可用网络！", Toast.LENGTH_LONG).show();
}
else
{
Toast.makeText(getApplicationContext(), "当前没有可用网络！", Toast.LENGTH_LONG).show();
}
}

/**
* 检查当前网络是否可用
*
* @param context
* @return
*/

public boolean isNetworkAvailable(Activity activity)
{
Context context = activity.getApplicationContext();
// 获取手机所有连接管理对象（包括对wi-fi,net等连接的管理）
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

if (connectivityManager == null)
{
return false;
}
else
{
// 获取NetworkInfo对象
NetworkInfo[] networkInfo = connectivityManager.getAllNetworkInfo();

if (networkInfo != null && networkInfo.length > 0)
{
for (int i = 0; i < networkInfo.length; i++)
{
System.out.println(i + "===状态===" + networkInfo[i].getState());
System.out.println(i + "===类型===" + networkInfo[i].getTypeName());
// 判断当前网络状态是否为连接状态
if (networkInfo[i].getState() == NetworkInfo.State.CONNECTED)
{
return true;
}
}
}
}
return false;
}
}