Android Webview无法显示PDF文件。存在与此问题相关的问题。您可以从this link查看
您的问题有多种解决方案，您可以选择最适合自己的解决方案。
1)使用react-native-pdf-view
2)使用Google文档作为查看器。尝试在Webview http://docs.google.com/gview?embedded=true&url=http://www.africau.edu/images/default/sample.pdf中加载此URL
3)使用Chrome自定义选项卡。

我选择了选项2，但面对的是谷歌文档查看器error，所以我做了这个hacky的事情来检查是否没有加载内容，以便刷新webview。

const retries = 10

const PdfViewerScreen = ({ route, navigation }: Props) => {
  const { pdfUrl } = route.params || {}
  const webview = useRef(null)
  const [tries, setTries] = useState(1)
  const [reset, setReset] = useState(Date.now())

  const isAndroid = Platform.OS === 'android'
  const base = !isAndroid
    ? ''
    : 'https://docs.google.com/gview?embedded=true&url='

  // Use date as reset to be able to 
  // reload the webview
  const uri = `${base}${pdfUrl}?t=${reset}`

  // Js code to get baseURI when 
  // webview is loaded. docs.google.com has a bug
  // where no content is returned.
  const myInjectedJs = `    
    (function(){ 
      window.ReactNativeWebView.postMessage(window.document.baseURI);
    })();`

  const onMessage = (event: WebViewMessageEvent) => {
    // Issue does not occur in iOS
    if(!isAndroid) return

    const baseURI = event.nativeEvent.data
    if (tries === retries) navigation.goBack()

    if (baseURI !== uri) {
      setReset(Date.now())
      setTries(tries + 1)
    }
  }

  return (
    <>
      <WebView
        ref={webview}
        javaScriptEnabled={true}
        domStorageEnabled={true}
        startInLoadingState={true}
        style={tailwind(`flex-1`)}
        injectedJavaScript={myInjectedJs}
        source={{ uri }}
        onMessage={onMessage}
        renderLoading={() => (
          <View style={tailwind('w-full h-full')}>
            <Loading />
          </View>
        )}
      />
    </>
  )
}

使用此格式的链接显示pdf：

https://drive.google.com/viewerng/viewer?embedded=true&url={your pdf url}’