She keeps replying "lol" and "ok".

Effort settles at whatever the two of you set. Answer "lol" with another paragraph and you have agreed the rate is fair, so she has no reason to renegotiate it. The move is not to work harder and not to sulk. It is to notice out loud, and to be amused rather than annoyed. Amusement is the entire difference between naming the imbalance and complaining about it.

The first one-word reply

A single "lol" is not a pattern. She may be on a train, half watching something, or she liked the joke and had nothing to add. This is where the light call-out belongs, once, and only if your last message deserved more than three letters. If it was a statement with nothing to answer, the short reply is on you, not her: ask something worth answering instead.

Two in a row

A pattern is starting, and now the reply matters. Do not send a third joke into the same gap. Keep your own message short too, match her length rather than out-writing it, and end on something that needs a real answer. The aim is an exchange that costs the same on both sides, so she can feel the difference when she puts more in.

A whole evening of it

She is answering, so she is not gone, and she is not investing, so she is not in it yet. End the conversation yourself, on a good note, before it runs dry. Leaving first while it is still pleasant is worth more than another hour of three-letter replies, and it gives her a reason to pick the thread up again.

Days of it

Across a long chat she keeps writing short, takes your attention and gives none back. That is the pattern, and the answer to it is to stop investing. Match her effort, stop opening every exchange, and let the next step be hers. If she wants the conversation, she will put something into it. If she does not, finding out cost you nothing more.

You are pointing at what she is doing, and someone who was never really in the conversation will let it end there. That is a real cost, and it is smaller than the alternative: three more weeks of writing to someone typing with one thumb.

She laughs and writes a real reply

The test is passed on both sides. Do not make a point of it and do not reward the longer message with a paragraph of your own. Answer at her new length, keep the energy, and steer toward something you could do together. Someone who opens up after a call-out often just prefers talking in person, so treat it as a reason to plan, not to text more.

Short, but fast, and she asks something back

That is a dry texter, not fading interest. Some people are brief on a screen and warm in person. Quick replies, a question in return, or a yes to plans all say she is in. The fix is not better texting. It is moving it off the screen sooner, to a call or a concrete plan.

Another "lol"

One more short reply after the call-out is her answer to it. Do not call it out a second time. Match her length, end the exchange yourself, and leave the next message to her.

Nothing at all

The call-out reached someone who was already leaving. That is the risk you took, and it cost one message instead of three weeks of writing to someone who was not reading closely. Do not follow up, and do not explain the joke.

How should I respond when a girl just says "lol"?

Short and amused. Name the low effort lightly and end with a question that needs a real answer. Do not send another joke, and do not ask what was funny.

She only texted "haha". What do I say now?

Look at your last message first. If it gave her nothing to answer, ask something that does. If it did, answer her "haha" in kind and hand the effort back with a playful challenge.

Is she just a dry texter, or is she not interested?

Watch what comes with the short replies. A dry texter answers quickly, asks something back now and then, and says yes to plans. Fading interest answers slowly, never asks anything, and goes vague when you suggest meeting.

How do I get her to text more instead of short replies?

You cannot write her into it. Match her length, make your messages worth answering, and stop carrying the conversation alone. People put in more when the effort is shared, and less when someone else is doing all of it for them.

What is a good comeback for a one-word text on Hinge?

Something that notices the reply with a smile and asks for more, like the vending machine line above. It works best early, before you have written several long messages, because a call-out lands lighter when you have not over-invested yet.

Should I stop texting a girl who gives one-word answers?

After a pattern, yes, in the sense that you stop leading every exchange. Not as a punishment and not with an announcement. You match her effort and let her make the next move. If she wants the conversation, she will.