30秒学会 React 片段 – Modal

Renders a Modal component, controllable through events.
To use the component, import Modal only once and then display it by passing a boolean value to the isVisible attribute.

• Use object destructuring to set defaults for certain attributes of the modal component.
• Define keydownHandler, a method which handles all keyboard events, which can be used according to your needs to dispatch actions (e.g. close the modal when <kbd>Esc</kbd> is pressed).
• Use React.useEffect() hook to add or remove the keydown event listener, which calls keydownHandler.
• Use the isVisible prop to determine if the modal should be shown or not.
• Use CSS to style and position the modal component.

代码实现

.modal {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  width: 100%;
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: rgba(0, 0, 0, 0.25);
  animation-name: appear;
  animation-duration: 300ms;
}

.modal-dialog {
  width: 100%;
  max-width: 550px;
  background: white;
  position: relative;
  margin: 0 20px;
  max-height: calc(100vh - 40px);
  text-align: left;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
  -webkit-animation-name: animatetop;
  -webkit-animation-duration: 0.4s;
  animation-name: slide-in;
  animation-duration: 0.5s;
}

.modal-header,
.modal-footer {
  display: flex;
  align-items: center;
  padding: 1rem;
}
.modal-header {
  border-bottom: 1px solid #dbdbdb;
  justify-content: space-between;
}
.modal-footer {
  border-top: 1px solid #dbdbdb;
  justify-content: flex-end;
}
.modal-close {
  cursor: pointer;
  padding: 1rem;
  margin: -1rem -1rem -1rem auto;
}
.modal-body {
  overflow: auto;
}
.modal-content {
  padding: 1rem;
}

@keyframes appear {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}
@keyframes slide-in {
  from {
    transform: translateY(-150px);
  }
  to {
    transform: translateY(0);
  }
}

使用样例

function Modal({ isVisible = false, title, content, footer, onClose }) {
  React.useEffect(() => {
    document.addEventListener('keydown', keydownHandler);
    return () => document.removeEventListener('keydown', keydownHandler);
  });

  function keydownHandler({ key }) {
    switch (key) {
      case 'Escape':
        onClose();
        break;
      default:
    }
  }

  return !isVisible ? null : (
    <div className="modal" onClick={onClose}>
      <div className="modal-dialog" onClick={e => e.stopPropagation()}>
        <div className="modal-header">
          <h3 className="modal-title">{title}</h3>
          <span className="modal-close" onClick={onClose}>
            &times;
          </span>
        </div>
        <div className="modal-body">
          <div className="modal-content">{content}</div>
        </div>
        {footer && <div className="modal-footer">{footer}</div>}
      </div>
    </div>
  );
}

//Add the component to the render function
function App() {
  const [isModal, setModal] = React.useState(false);

  return (
    <React.Fragment>
      <button onClick={() => setModal(true)}>Click Here</button>
      <Modal
        isVisible={isModal}
        title="Modal Title"
        content={<p>Add your content here</p>}
        footer={<button>Cancel</button>}
        onClose={() => setModal(false)}
      />
    </React.Fragment>
  );
}

ReactDOM.render(<App />, document.getElementById('root'));