Yashotantra Academy logo
← React Native theorytheory 0/50 · 0%
level 1
Curious · 0 XP
streak
0d
perfect
0
badges
0

100 XP to Apprentice

Components · easy

11. Forms and TextInput

Controlled text input for amounts and addresses.

1 min read3 questionsup to 50 XPtopic 11/50

Read in another language

AI translates the explanation and quiz text while preserving code and answer scoring.

`TextInput` is controlled the same way as an HTML input: you supply `value` and update it via `onChangeText`. For numeric wallet amounts, `keyboardType="decimal-pad"` improves UX.

import { TextInput } from "react-native";
import { useState } from "react";

function AmountInput() {
  const [amount, setAmount] = useState("");
  return (
    <TextInput
      value={amount}
      onChangeText={setAmount}
      keyboardType="decimal-pad"
      placeholder="0.0"
    />
  );
}

Always validate and sanitize input before parsing it into a number or a wei amount — users can paste arbitrary text, and a bad `parseFloat` on an empty string yields `NaN`.

How to study this topic

  1. 1. Read the explanation once end to end, skipping the code.
  2. 2. Re-read the code snippets and say out loud what each line does.
  3. 3. Answer the quiz without scrolling back — that is the real check.
  4. 4. Read every explanation, even for the answers you got right.

Scoring

  • · Up to 30 XP from quiz accuracy.
  • · +15 XP for a perfect first attempt.
  • · +5 XP while a 3-day streak is running.
  • · 75% or higher marks the topic complete.

Check your understanding

  1. 1. What prop updates a controlled TextInput's value?

  2. 2. Which keyboardType suits decimal amounts?

  3. 3. Why validate text before parsing to a number?

Badges

First light
Pass your first topic
Sharp shooter
3 perfect first-try quizzes
On a roll
Study 3 days in a row
Week warrior
Study 7 days in a row
Grinder
Earn 500 XP
Deep diver
Earn 1500 XP