下载Flutter InAppWebview中的文件

InAppWebView webView = InAppWebView(
  initialUrl: 'https://example.com',
);

webView.onLoadStop.listen((InAppWebViewController controller, String url) async {
  // 执行JavaScript代码，触发文件下载
  await controller.evaluateJavascript(source: 'document.getElementById("downloadButton").click();');
});

<button id="downloadButton" onclick="downloadFile()">下载文件</button>

<script>
function downloadFile() {
  // 执行文件下载操作
}
</script>

function downloadFile() {
  var xhr = new XMLHttpRequest();
  xhr.open('GET', 'https://example.com/file.pdf', true);
  xhr.responseType = 'blob';

  xhr.onload = function(e) {
    if (this.status == 200) {
      var blob = new Blob([this.response], {type: 'application/pdf'});
      var url = URL.createObjectURL(blob);

      // 创建一个隐藏的a标签，模拟点击下载
      var a = document.createElement('a');
      a.style.display = 'none';
      a.href = url;
      a.download = 'file.pdf';
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
    }
  };

  xhr.send();
}