Planning a project, need your advice (web development, Android, iOS)?

Question

Mobile development

Good evening dear locals.
Introduction .
I’ll clarify right away that I have never been a programmer and have very little connection with any programming (correct the layout; understand where the variable comes from in php; understand that this is java, but this is objective c and I can do similar things. No more).
Due to the fact that the main activity leaves enough free time - I decided to delve into programming. On web and mobile. Since, right now, there is no goal to become a strong %name of the language%-programmer, I decided to try a little bit of everything from the web and mobile. As you know, in addition to textbooks and manuals, language + technology is best studied when they immediately start practicing and trying to make a product.
The main part, the crux of the matter .
I want to make an application for Android and iOS. The essence of the application in a nutshell: this is a chat where you can find an interlocutor according to the criteria, but still you can’t find exactly someone. That is, I see this application like this - a person enters it, selects a criterion (for example, "hobby - auto") and connects him to a chat with the same person who selected this criterion. But since 10 people can choose this criterion, it will be connected to only one of them. During the chat, you can chat (naturally), take a photo on the camera and send it to the chat window.
I would also like the interlocutor to know at what distance he is from the other interlocutor. That is, let's say, "you have connected with an interlocutor who also loves cars and now she is 135 kilometers away from you."
Chat history is only saved for 5 minutes,
In general, this is the kind of application I want to make. Whether it is necessary or not is another question, I'm just curious.
List of questions to which I would like to see your answers :
1. Is it enough to know Java (for Android) and Objective C (for iOS) to implement such an application? Do you need to know any other languages ​​or technologies? If you need to know something else - tell me, please, what?
2. How difficult is it to write such an application for Android and iOS? If I start learning these languages ​​from scratch, then, theoretically, can I do something similar, albeit crooked and raw, in a month? Three-five-year?
3. * I don’t fully imagine what I’ll ask now, but whoever fumbles will understand:
Is it possible to write some web server in PHP + MySQL, which will be the heart of such applications, and the applications themselves for Android and iOS clients will be the simplest system that will be beautifully designed and will interact with the server?
4. How are applications of this type generally written? What technologies are used and what does the scheme of such applications look like? What programming languages ​​are needed?
5. If we talk strictly about the functionality that I indicated above - how much theoretically (at least approximately, I understand everything that there are no specifics without a clear technical specification) can the development of such an application for Android / iOS cost?
Final part .
Friends, a small request for those who have free 15 minutes a day and the opportunity / desire to answer a couple of questions and turn their thoughts in the right direction:
I would very much like to sometimes and briefly communicate with knowledgeable people. Search engines and forums are modern, but sometimes you need to throw some question into the messenger window, which will take an experienced person 2 minutes, and get a short answer. Or not a question, but some opinion about something in programming.
I understand everything, time is money, no one wants to sit and write sheets-manuals - all this is not necessary. It’s enough just to know that you have a person in your contacts who, in case of getting stuck or thinking about how to do better, will simply point you in the direction and say that it’s worth google.
If anyone has a desire to help with advice from time to time, please leave some of your contacts. What is convenient for you, what do you often use. Interested in developers who work with the web (HTML+CSS+JS and PHP+MySQL, or alternative) and mobile (Android and iOS). I guarantee tact and the ability to ask questions correctly, taking up your time as little as possible.
Well, no, it's not. In any case, thanks for stopping by and paying attention to my problem!

Answer 1

Making a good chat is not easy. I wrote telegrams for android, and in general this is a painful task. But realizable.
1. In theory, this is enough. In practice, this is not possible. Learning two languages ​​and the features of two very different platforms from scratch will be very problematic. And for a long time. I recommend going in the direction of some cross-platform framework, such as PhoneGap. Or you can try a hybrid one, like Xamarin, but it's expensive.
2. If in my free time I would lay down 2-3 months for a platform at least
3. In any case, you need a server. I'm not sure if PHP + MySQL will do, but for example NodeJS is fine. Combined with PhoneGap (for example) you only need to learn 1 language - JavaScript. And in combination with Xamarin - only C #, and you can write anything on it.
4. To learn how to write, read for example "Perfect Code" by McConnell or anything by Joel Spolsky
5. I'm pretty bad at estimating costs, but I see around 100k per platform.

Answer 2

Objective C requires a fairly high level of skill even to learn it.
If you say that "I've never been a programmer", then it might be more practical to take some simpler task and start learning Objective C programming on it. Still, it's better to master it gradually, from simple to complex. And the task you described will require good skills even for an experienced programmer.

Answer 3

If you already use Java, then the backend is quite possible to write on it.