javascript - React中setState方法无效

看代码

class Background extends React.Component{
    constructor(opts) {
        super(opts);
        this.initStatus();
    }
    initStatus() {
        this.state = {
            effect: false
        }
    }
    render(){
        this.initStatus();

        return <p className={cs({background: true, effect: this.state.effect})}>
            <p className="background-pannel">
                <p className="background-image-back"></p>
            </p>
            <p className="background-pannel">
                <p className="background-image"></p>
            </p>
        </p>
    }
    
    componentDidMount() {

        this.setState({effect: true}, ()=>{
            console.log(this.state.effect);
        })
    }
}

export { Background }

为什么没有效果，打印出来的effect值依然是false？