Android默认的WebView（Android 4.4以前）无法完全支持HTML5视频的所有功能，包括刮擦功能。但是可以通过使用第三方WebView库（例如CrossWalk）来解决此问题，或者使用JavaScript来模拟刮擦功能。以下是一个使用JavaScript模拟刮擦功能的示例代码：

HTML：

CSS：

#scrubberWrapper {
   position: relative;
}

#scrubber {
   position: absolute;
   top: 0;
   left: 0;
   width: 0;
   height: 10px;
   background-color: red;
   opacity: 0.5;
   z-index: 100;
}

JavaScript：

var videoPlayer = document.getElementById('videoPlayer');
var scrubber = document.getElementById('scrubber');
var isMouseDown = false;

videoPlayer.addEventListener('timeupdate', function() {
   scrubber.style.width = (videoPlayer.currentTime / videoPlayer.duration) * 100 + '%';
});

scrubber.addEventListener('mousedown', function() {
   isMouseDown = true;
});

document.addEventListener('mousemove', function(event) {
   if (isMouseDown) {
      var scrubberWrapper = document.getElementById('scrubberWrapper');
      var deltaX = event.pageX - scrubberWrapper.offsetLeft;
      var percent = deltaX / scrubberWrapper.offsetWidth;
      videoPlayer.currentTime = percent * videoPlayer.duration;
   }
});

document.addEventListener('mouseup', function() {
   isMouseDown = false;
});