React native - change state of dynamic elements

Question

I'm trying to loopover an array to render items in a list (in react native). Every item has a button. How can I change the background color of this specific button, when someone clicks it? I already tried .setState but the problem is, that it changes the background color of every button in the list.

 this.setState({btnColor: 'red' }); 

What can I do? Is there a way to create new states dynamically?

Thank you.

Answer 1

You can take such approach:

 class App extends React.Component {
  state = {
    colors: {},
    btnIds: [1, 2, 3]
  };

  render() {
    return (
      <div>
        {this.state.btnIds.map(x => (
          <button
            onClick={() => {
              this.setState(ps => ({
                colors: {
                  ...ps.colors,
                  [x]: "red"
                }
              }));
            }}
            style={{ backgroundColor: this.state.colors[x] || "" }}
          >
            {x}
          </button>
        ))}
      </div>
    );
  }
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.9/angular.min.js"></script>
<div id="root"/>

react demo though IMHO same should apply on RN.