{"id":5602,"date":"2022-03-21T15:09:56","date_gmt":"2022-03-21T07:09:56","guid":{"rendered":"http:\/\/39.106.39.94\/?p=5602"},"modified":"2022-03-21T15:20:23","modified_gmt":"2022-03-21T07:20:23","slug":"state%e7%9a%84%e9%97%ae%e9%a2%98","status":"publish","type":"post","link":"https:\/\/lilichao.com\/?p=5602","title":{"rendered":"state\u7684\u95ee\u9898"},"content":{"rendered":"\n

\u5f15\u51fa\u95ee\u9898<\/h2>\n\n\n\n

\u6709\u4e86state\uff0c\u4f7f\u5f97React\u7ec4\u4ef6\u53ef\u4ee5\u968f\u7740\u67d0\u4e2a\u503c\u7684\u6539\u53d8\u800c\u6539\u53d8\uff0c\u6211\u4eec\u65e0\u9700\u518d\u5728\u67d0\u4e2a\u503c\u53d1\u751f\u53d8\u5316\u540e\u91cd\u65b0\u624b\u52a8\u5bf9\u754c\u9762\u8fdb\u884c\u6784\u5efa\uff0cReact\u4f1a\u66ff\u6211\u4eec\u5b8c\u6210\u8fd9\u4e9b\u5de5\u4f5c\uff0c\u5927\u5927\u964d\u4f4e\u4e86\u6211\u4eec\u5f00\u53d1\u7684\u96be\u5ea6\u3002<\/p>\n\n\n\n

\u4f46\u662fstate\u4e2d\u8fd8\u9690\u85cf\u7740\u4e00\u4e9b\u4e0d\u592a\u5bb9\u6613\u53d1\u73b0\u7684\u95ee\u9898\uff0c\u73b0\u5728\u5047\u8bbe\u6211\u4eec\u9700\u8981\u5f00\u53d1\u4e00\u4e2a\u8ba1\u6570\u5668\u7ec4\u4ef6\uff0c\u8fd9\u4e2a\u7ec4\u4ef6\u975e\u5e38\u7b80\u5355\uff0c\u6709\u4e00\u4e2a\u6309\u94ae\u548c\u4e00\u4e2a\u6570\u5b57\uff0c\u6bcf\u70b9\u51fb\u4e00\u6b21\u6309\u94ae\u6570\u5b57\u5c31\u4f1a\u589e\u52a01\uff0c\u5927\u6982\u957f\u6210\u8fd9\u4e2a\u6837\u5b50\uff1a<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

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Counter.js<\/p>\n\n\n\n

import React, {useState} from 'react';\n\nconst Counter = () => {\n    const [count, setCount] = useState(1);\n\n    const clickHandler = ()=> {\n        setCount(count+1);\n    }\n\n    return (\n        <div>\n            <h2>{count}<\/h2>\n            <button onClick={clickHandler}>+1<\/button>\n        <\/div>\n    );\n};\n\nexport default Counter;<\/code><\/pre>\n\n\n\n
\u5728clickHandler()<\/code>\u4e2d\uff0c\u6211\u4eec\u8c03\u7528\u4e86setCount(count+1)<\/code>\u6765\u5bf9count\u8fdb\u884c\u66f4\u65b0\uff0c\u6bcf\u6b21\u66f4\u65b0\u90fd\u662f\u5728\u524d\u4e00\u6b21\u503c\u7684\u57fa\u7840\u4e0a\u589e\u52a01\u3002\u8fd9\u4e2a\u4ee3\u7801\u8fd9\u4e48\u5199\u5728\u5927\u90e8\u5206\u7684\u573a\u666f\u4e0b\u90fd\u4e0d\u4f1a\u5e26\u6765\u4efb\u4f55\u7684\u95ee\u9898\uff0c\u4f46\u662f\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\u5c31\u4e0d\u4e00\u5b9a\u4e86\u3002<\/p>\n\n\n\n
\u4ea7\u751f\u95ee\u9898\u7684\u539f\u56e0<\/h2>\n\n\n\n
\u6f14\u793a\u95ee\u9898\u4e4b\u524d\uff0c\u5148\u6765\u8bf4\u8bf4\u4ea7\u751f\u8fd9\u4e2a\u95ee\u9898\u7684\u539f\u56e0\u3002\u5728React\u4e2d\u6211\u4eec\u901a\u8fc7setState()<\/code>\u4fee\u6539\u72b6\u6001\u90fd\u662f\u5f02\u6b65\u5b8c\u6210\u7684\uff0c\u6362\u53e5\u8bdd\u8bf4\u5e76\u4e0d\u662f\u8c03\u7528\u5b8csetState()<\/code>\u540e\u72b6\u6001\u7acb\u523b\u5c31\u53d1\u751f\u53d8\u5316\uff0c\u800c\u662f\u9700\u8981\u7b49\u4e0a\u4e00\u6bb5\u65f6\u95f4\uff0c\u5f53\u7136\u8fd9\u6bb5\u65f6\u95f4\u4e0d\u4f1a\u5f88\u957f\u3002\u50cf\u4e0a\u8fb9\u7684\u6848\u4f8b\u4e2dstate\u7684\u4fee\u6539\u867d\u7136\u662f\u5f02\u6b65\u5b8c\u6210\u7684\uff0c\u4f46\u662f\u7531\u4e8e\u529f\u80fd\u6bd4\u8f83\u7b80\u5355\uff0c\u7b49\u5f85\u65f6\u95f4\u51e0\u4e4e\u53ef\u4ee5\u5ffd\u7565\u4e0d\u8ba1\u3002\u4f46\u968f\u7740\u529f\u80fd\u590d\u6742\u5ea6\u7684\u63d0\u5347\uff0c\u8fd9\u4e2a\u95f4\u9694\u4f1a\u9010\u6e10\u589e\u591a\u3002<\/p>\n\n\n\n
\u95ee\u9898\u6f14\u793a<\/h2>\n\n\n\n
\u5047\u8bbe\u8c03\u7528setState()<\/code>\u540e1\u79d2state\u7684\u503c\u624d\u4f1a\u771f\u7684\u6539\u53d8\uff0c\u8fd9\u65f6\u5982\u679c\u6211\u4eec\u8fde\u7eed\u70b9\u51fb\u6309\u94ae2\u6b21\uff0c\u7b2c1\u6b21\u70b9\u51fb\u6309\u94ae\u65f6count\u503c\u662f1\uff0c\u7b2c2\u6b21\u70b9\u51fb\u901f\u5ea6\u6bd4\u8f83\u5feb\uff0c\u4ece\u800c\u4e24\u6b21\u95f4\u9694\u6ca1\u6709\u8d85\u8fc71\u79d2\uff0c\u6b64\u65f6\u7684count\u503c\u4f9d\u7136\u662f1\uff0c\u8fd9\u5c31\u5bfc\u81f4\u6211\u70b9\u51fb\u4e86\u4e24\u6b21\u6309\u94ae\uff0c\u4f46\u662f\u503c\u53ea\u589e\u52a0\u4e861\u6b21\uff0c\u56e0\u4e3a\u4e24\u6b21count+1\u4e2d\u7684count\u90fd\u662f1\u3002<\/p>\n\n\n\n
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import React, {useState} from 'react';\n\nconst Counter = () => {\n    const [count, setCount] = useState(1);\n    const clickHandler = ()=> {\n        setTimeout(()=>{\n            setCount(count+1);\n        }, 1000);\n    }\n    return (\n        <div>\n            <h2>{count}<\/h2>\n            <button onClick={clickHandler}>+1<\/button>\n        <\/div>\n    );\n};<\/code><\/pre>\n\n\n\n
\u8fd9\u6837\u4e00\u6765\uff0c\u70b9\u51fb\u6309\u94ae\u540e1\u79d2setCount()<\/code>\u624d\u4f1a\u8c03\u7528\uff0c\u5982\u679c\u6211\u4eec\u57281\u79d2\u5185\u70b9\u51fb\u6309\u94ae\u591a\u6b21\uff0c\u4f60\u4f1a\u53d1\u73b0\u6309\u94ae\u6570\u503c\u53ea\u4f1a\u589e\u52a0\u4e00\u6b21\uff0c\u5f88\u663e\u7136\u6211\u4eec\u4e0d\u5e0c\u671b\u8fd9\u79cd\u60c5\u51b5\u51fa\u73b0\u3002<\/p>\n\n\n\n
\u89e3\u51b3\u95ee\u9898<\/h2>\n\n\n\n
\u8981\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u5176\u5b9e\u4e5f\u4e0d\u96be\uff0c\u5728setState()<\/code>\u65f6\u9664\u4e86\u76f4\u63a5\u4f20\u9012\u4e00\u4e2a\u6307\u5b9a\u503c\u4ee5\u5916\uff0cReact\u8fd8\u5141\u8bb8\u6211\u4eec\u901a\u8fc7\u4e00\u4e2a\u56de\u8c03\u51fd\u6570\u6765\u4fee\u6539state\uff0c\u56de\u8c03\u51fd\u6570\u7684\u8fd4\u56de\u503c\u5c31\u662f\u65b0\u7684state\u7684\u503c\uff0c\u4f7f\u7528\u56de\u8c03\u51fd\u6570\u7684\u597d\u5904\u662f\uff0c\u8fd9\u4e2a\u56de\u8c03\u51fd\u6570\u4f1a\u786e\u4fdd\u4e0a\u4e00\u6b21\u7684setState()<\/code>\u8c03\u7528\u5b8c\u6210\u540e\u624d\u88ab\u8c03\u7528\uff0c\u540c\u65f6\u4f1a\u4f7f\u7528\u6700\u65b0\u7684state\u503c\u4f5c\u4e3a\u56de\u8c03\u51fd\u6570\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u3002\u8fd9\u6837\u4e00\u6765\u5c31\u6709\u6548\u7684\u907f\u514d\u4e86\u65e0\u6cd5\u6b63\u786e\u83b7\u53d6\u4e0a\u4e00\u4e2astate\u503c\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n
\u4e0a\u8fb9\u6848\u4f8b\u4e2d\u7684 setCount(count+1);<\/code>\u53ef\u4ee5\u6539\u6210\u8fd9\u4e2a\u6837\u5b50\uff1a<\/p>\n\n\n\n
setCount(prevState => prevState+1);<\/pre>\n\n\n\n
\u8fd9\u6837\u4e00\u6765\uff0c\u51fd\u6570\u4e2d\u7684prevState\u603b\u662f\u4e0a\u6b21\u4fee\u6539\u540e\u7684\u6700\u65b0state\uff0c\u907f\u514d\u518d\u6b21\u51fa\u73b0\u70b9\u51fb\u591a\u6b21\u6309\u94ae\u53ea\u4fee\u6539\u4e00\u6b21\u7684\u95ee\u9898\u3002\u603b\u7684\u6765\u8bf4\uff0c\u5f53\u6211\u4eec\u4fee\u6539\u4e00\u4e2astate\u7684\u503c\u800c\u9700\u8981\u4f9d\u8d56\u4e8e\u524d\u8fb9\u7684\u503c\u8fdb\u884c\u8ba1\u7b97\u65f6\uff0c\u6700\u5b89\u5168\u7684\u65b9\u5f0f\u5c31\u662f\u901a\u8fc7\u56de\u8c03\u51fd\u6570\u800c\u4e0d\u662f\u76f4\u63a5\u4fee\u6539\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f15\u51fa\u95ee\u9898 \u6709\u4e86state\uff0c\u4f7f\u5f97React\u7ec4\u4ef6\u53ef\u4ee5\u968f\u7740\u67d0\u4e2a\u503c\u7684\u6539\u53d8\u800c\u6539\u53d8\uff0c\u6211\u4eec\u65e0\u9700\u518d\u5728\u67d0\u4e2a\u503c\u53d1\u751f\u53d8\u5316\u540e\u91cd\u65b0\u624b\u52a8\u5bf9 […]<\/p>\n","protected":false},"author":1,"featured_media":5609,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[198],"tags":[200,202,199,201,203],"_links":{"self":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/5602"}],"collection":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5602"}],"version-history":[{"count":3,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/5602\/revisions"}],"predecessor-version":[{"id":5610,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/5602\/revisions\/5610"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/media\/5609"}],"wp:attachment":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5602"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5602"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5602"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}