我是个善于反应的人。我使用的材料用户界面和材料用户界面图标,并作出反应,以创建一个标题与前进和后退按钮,这样用户可以滚动的图片在显示。当我按正向按钮时,“索引2”中的图片没有显示任何内容。当我按后退按钮时,“索引0”中的图片是空白的(奇怪,对吗?)在我看来这是个超级奇怪的虫子。这里有什么东西我遗漏了吗?这对我来说毫无意义。
这是我的代码(正如您所看到的,我仍然在编辑东西,所以当我从Material抓取它时,我仍然有默认的文本)。
import React from 'react';
import { makeStyles } from '@material-ui/core/styles';
import clsx from 'clsx';
import Card from '@material-ui/core/Card';
import CardHeader from '@material-ui/core/CardHeader';
import CardMedia from '@material-ui/core/CardMedia';
import CardContent from '@material-ui/core/CardContent';
import CardActions from '@material-ui/core/CardActions';
import Collapse from '@material-ui/core/Collapse';
import Avatar from '@material-ui/core/Avatar';
import IconButton from '@material-ui/core/IconButton';
import Typography from '@material-ui/core/Typography';
import { red } from '@material-ui/core/colors';
import FavoriteIcon from '@material-ui/icons/Favorite';
import ShareIcon from '@material-ui/icons/Share';
import ExpandMoreIcon from '@material-ui/icons/ExpandMore';
import MoreVertIcon from '@material-ui/icons/MoreVert';
import ArrowForwardIosIcon from '@material-ui/icons/ArrowForwardIos';
import ArrowBackIosIcon from '@material-ui/icons/ArrowBackIos';
import image2019_0201 from '../images/2019_0201.jpeg';
import image2019_0202 from '../images/2019_0202.jpeg';
import image2019_0203 from '../images/2019_0203.jpeg';
const images = [
image2019_0201,
image2019_0202,
image2019_0203,
];
const imageText = [
"February 15, 2019",
"text2",
"text3"
]
const useStyles = makeStyles((theme) => ({
root: {
maxWidth: 345,
},
media: {
height: 0,
paddingTop: '56.25%', // 16:9
},
expand: {
transform: 'rotate(0deg)',
marginLeft: 'auto',
transition: theme.transitions.create('transform', {
duration: theme.transitions.duration.shortest,
}),
},
expandOpen: {
transform: 'rotate(180deg)',
},
avatar: {
backgroundColor: red[500],
},
}));
export default function Year2019() {
const classes = useStyles();
const [expanded, setExpanded] = React.useState(false);
const [currentImageIndex, setCurrentImageIndex] = React.useState(0)
const handleExpandClick = () => {
setExpanded(!expanded);
};
const handleForwardClick = () => {
console.log("current index", currentImageIndex);
if (currentImageIndex < images.length) {
setCurrentImageIndex(currentImageIndex + 1);
}
else {
setCurrentImageIndex(0);
}
console.log("new index", currentImageIndex);
}
const handleBackClick = () => {
console.log("current index", currentImageIndex);
if (currentImageIndex == 0) {
setCurrentImageIndex(images.length);
}
else {
setCurrentImageIndex(currentImageIndex - 1);
}
console.log("new index", currentImageIndex);
}
return (
<Card className={classes.root}>
<CardHeader
title="Title"
subheader="February 15, 2019"
/>
<CardMedia
className={classes.media}
image={images[currentImageIndex]}
title="image2019_0201"
/>
<CardContent>
<Typography variant="body2" color="textSecondary" component="p">
Waiting for the shuttle.
</Typography>
</CardContent>
<CardActions disableSpacing>
<IconButton aria-label="back" onClick={handleBackClick}>
<ArrowBackIosIcon/>
</IconButton>
<IconButton aria-label="forward" onClick={handleForwardClick}>
<ArrowForwardIosIcon/>
</IconButton>
<IconButton
className={clsx(classes.expand, {
[classes.expandOpen]: expanded,
})}
onClick={handleExpandClick}
aria-expanded={expanded}
aria-label="show more"
>
<ExpandMoreIcon />
</IconButton>
</CardActions>
<Collapse in={expanded} timeout="auto" unmountOnExit>
<CardContent>
<Typography paragraph>Method:</Typography>
<Typography paragraph>
Heat 1/2 cup of the broth in a pot until simmering, add saffron and set aside for 10
minutes.
</Typography>
<Typography paragraph>
Heat oil in a (14- to 16-inch) paella pan or a large, deep skillet over medium-high
heat. Add chicken, shrimp and chorizo, and cook, stirring occasionally until lightly
browned, 6 to 8 minutes. Transfer shrimp to a large plate and set aside, leaving chicken
and chorizo in the pan. Add pimentón, bay leaves, garlic, tomatoes, onion, salt and
pepper, and cook, stirring often until thickened and fragrant, about 10 minutes. Add
saffron broth and remaining 4 1/2 cups chicken broth; bring to a boil.
</Typography>
<Typography paragraph>
Add rice and stir very gently to distribute. Top with artichokes and peppers, and cook
without stirring, until most of the liquid is absorbed, 15 to 18 minutes. Reduce heat to
medium-low, add reserved shrimp and mussels, tucking them down into the rice, and cook
again without stirring, until mussels have opened and rice is just tender, 5 to 7
minutes more. (Discard any mussels that don’t open.)
</Typography>
<Typography>
Set aside off of the heat to let rest for 10 minutes, and then serve.
</Typography>
</CardContent>
</Collapse>
</Card>
);
}
发布于 2022-01-24 02:29:36
在您的处理程序函数中,数组索引可能超出范围。因此,应该修改处理程序函数,如下所示:
const handleForwardClick = () => {
if (currentImageIndex < (images.length - 1)) {
setCurrentImageIndex(currentImageIndex + 1);
}
else {
setCurrentImageIndex(0);
}
}
const handleBackClick = () => {
if (currentImageIndex == 0) {
setCurrentImageIndex(images.length - 1);
}
else {
setCurrentImageIndex(currentImageIndex - 1);
}
}
https://stackoverflow.com/questions/70828103
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