Question

我正在初始加载数据。当用户单击按钮添加识别时，api调用将其添加并返回。我将新的帖子添加到数组中，但是新的更新不呈现。返回对象和对象数组是相同的对象类型。当我重新加载页面时，将显示新帖子，只是不在add函数上。有什么我想念的吗？

  const [recognitions, setRecognitions] = useState([]);

useEffect(() => {
    Api.GetRecognitions(params)
      .then(response => {
        const items = response || [];
        setRecognitions(recognitions => [...recognitions, ...items]);
      })
  }, [setRecognitions]);

const handleAddPost = () => {
    Api.AddRecognition(params)
    .then(response => {
      const newPost = response;
      setRecognitions(recognitions=> [...recognitions, newPost])
    });
  }

<Form.Group>
      <Form.Field>
        <Button basic color='blue' onClick={handleAddPost}>Add</Button>
      </Form.Field>
    </Form.Group>
    <Form.Group>
      <Form.Field>
      {recognitions.map(recognition => (
        <RecogWallPost 
          key={recognition.recogStagingId}
          recognition={recognition}
          participantId={participantId}
        />
      )
      )}
      </Form.Field>
    </Form.Group>

Answer 1

您想传递[setRecognitions]，而不是传递useEffect作为[recognitions]的第二个参数。这告诉useEffect挂钩在每次识别更改时运行，它在handleAddPost内部执行。

Answer 2

您必须创建一个异步函数，然后按以下方式使用它：

import requests


params = {
    'switchLocale': 'y',
    'siteEntryPassthrough': 'true'
}


def main(url, params):
    r = requests.get(url, params=params)
    with open("test.pdf", 'wb') as f:
        f.write(r.content)


main("https://www.blackrock.com/uk/individual/literature/annual-report/blackrock-index-selection-fund-en-gb-annual-report-2019.pdf", params)

反应使用状态挂钩不更新

2 个答案: