网络判断工具类

<a target=_blank href="http://blog.csdn.net/lmj623565791/article/details/38965311">转载来源</a>

/**
 * 跟网络相关的工具类
 */
public class NetUtils {
    private NetUtils() {
        /* cannot be instantiated */
        throw new UnsupportedOperationException("cannot be instantiated");
    }

    /**
     * 判断网络是否连接
     *
     * @param context
     * @return
     */
    public static boolean isConnected(Context context) {
        ConnectivityManager connectivity = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        if (null != connectivity) {

            NetworkInfo info = connectivity.getActiveNetworkInfo();
            if (null != info && info.isConnected()) {
                if (info.getState() == NetworkInfo.State.CONNECTED) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * 判断是否是wifi连接
     */
    public static boolean isWifi(Context context) {
        ConnectivityManager cm = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        return cm != null && cm.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI;
    }

    /**
     * 打开网络设置界面
     */
    public static void openSetting(Activity activity) {
        Intent intent = new Intent("/");
        ComponentName cm = new ComponentName("com.android.settings",
                "com.android.settings.WirelessSettings");
        intent.setComponent(cm);
        intent.setAction("android.intent.action.VIEW");
        activity.startActivityForResult(intent, 0);
    }

}