How to open IOS keyboard when focusing material-ui TextField?

I can't get the IOS keyboard on mobile to open on focus. Any proposed solutions or workarounds? I have fiddled with autoFocus property but it won't open the keyboard. Current code:

class Input extends React.Component {
    muiTextFieldRef = null;
    get inputNode() {
      if (!this.muiTextFieldRef) {
         return null;
      }
      return this.muiTextFieldRef.getInputNode();
    }

    componentDidMount() {
      if(this.inputNode) {
        this.inputNode.focus();
      }
    }

    render() {
      return (
        <TextField
           ref={(muiTextFieldRef) => {
             this.muiTextFieldRef = muiTextFieldRef;
           }}
        />
      );
    }
}