您不能直接注入CSS，但是可以使用Javascript来操纵页面dom。
public class MainActivity extends ActionBarActivity { WebView webView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); webView = new WebView(this); setContentView(webView); // Enable Javascript webView.getSettings().setJavascriptEnabled(true); // Add a WebViewClient webView.setWebViewClient(new WebViewClient() { @Override public void onPageFinished(WebView view, String url) { // Inject CSS when page is done loading injectCSS(); super.onPageFinished(view, url); } }); // Load a webpage webView.loadUrl("https://www.google.com");}// Inject CSS method: read style.css from assets folder// Append stylesheet to document headprivate void injectCSS() { try { InputStream inputStream = getAssets().open("style.css"); byte[] buffer = new byte[inputStream.available()]; inputStream.read(buffer); inputStream.close(); String enpred = base64.enpreToString(buffer, base64.NO_WRAP); webView.loadUrl("javascript:(function() {" + "var parent = document.getElementsByTagName('head').item(0);" + "var style = document.createElement('style');" + "style.type = 'text/css';" + // Tell the browser to base64-depre the string into your script !!! "style.innerHTML = window.atob('" + enpred + "');" + "parent.appendChild(style)" + "})()"); } catch (Exception e) { e.printStackTrace(); }}@Overridepublic boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); }}
