android 查看当前网络状态

  /**
     * check net work
     * 
     * @param context
     * @return
     */ 
    public static boolean hasNetwork(Context context) { 
        ConnectivityManager con = (ConnectivityManager) context 
                .getSystemService(Context.CONNECTIVITY_SERVICE); 
        NetworkInfo workinfo = con.getActiveNetworkInfo(); 
        if (workinfo == null || !workinfo.isAvailable()) { 
            Toast.makeText(context, "当前无网络连接,请稍后重试", Toast.LENGTH_SHORT).show(); 
            return false; 
        } 
        return true; 
    }