我正在尝试在React Native中构建测验应用程序，但导航到以前的报价时遇到问题

Question

I am trying to build a quiz app in react native, but I am having problem navigating to Previous quotes. This is my code, the prevQuote function isn't working.

prevQuote = () => {
    const { activeQuoteIndex } = this.state;
    let prevQuote = activeQuoteIndex;
    this.setState({
        prevQuote: activeQuoteIndex - 1,
    });
};

nextQuote = () => {
    const { activeQuoteIndex } = this.state;

    if (activeQuoteIndex < quotes.length - 1) {
        this.setState({
            activeQuoteIndex: Math.floor(Math.random() * activeQuoteIndex + 10),
        });
    }

Answer 1

Try calling setState with a callback like so:

this.setState((state) => ({
    prevQuote: state.activeQuoteIndex - 1,
});

More info here .