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Android WebView

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James Ketrenos edited this page Sep 2, 2013 · 1 revision

1. Arch & Components

  • Android WebView in AOSP will be based on AwContents which is on top of Content API and Content View
  • Different from Content API, it also depends on components originally from chrome browser, now in standalone modules, located in components/, including components of auto_login_parser, navigation_interception, visitedlink_browser, visitedlink_renderer and web_contents_delegate_android. These are useful for pages.
  • No renderer process(in-process renderer) so no sandbox mechanism
  • Graphics architecture is very different from content shell. It's still ongoing and expected to support software and hardware output.

2. API

  • API is somewhat similar to EFL webview. No exposal about internal browser/renderer/gpu processes
  • Capabilities to load URL and events or callbacks of page loading
  • JavaScript API extension via addJavaScriptInterface. It allows JavaScript call to Java code, but reverse direction is not supported
  • Kinds of APIs to provide page change notifications, callbacks for web pages

3. Message Loop & Events processing

  • Integrate with Android Message handling by leveraging ContentView
  • Native code sets timer into Message Loop of Java side

4. Graphics

  • The rendering now is hardware acceleration by using chromium compositors.
  • The output of compositor support software and hardware surface outputs.
  • The architecture of hardware acceleration is different from others like content shell but it's like ChromeOS. Now it's in early stage, will use UberCompositor for software output.

5. WebAPI extension

  • The API addJavaScriptInterface is for JavaScript API extension but only for the direction from JavaScript to Java code
  • The reverse call direction(Java -> JavaScript) is not supported.
  • addJavaScriptInterface is supported via NPObject mechanism which is previously used by NPAPI plugin. It supports out-of-process accessing though it's not needed in WebView now.
  • Event notification from Java side seems not supported.

6. Details and Coverage of API

  • WebViewClient for page changed notifications
  • WebChromeClient for callbacks to participate in rendering logic
  • Native Code/JS interaction
  • Page loading
  • Navigation & History
  • Text Search
  • Event handling
  • Trackball, touch, keyboard
  • No support for mouse event
  • Settings: Encoding
  • Page Info: Title, favicon
  • HTTPS/SSL
  • Page loading status, scale, redirects, override url, etc.

7. Source code

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