Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
600 views
in Technique[技术] by (71.8m points)

Playing HTML5 video on fullscreen in android webview

Well, I've been searching few days already, how to display HTML5 video in full-screen mode on android WebView.

I managed to play HTML5 videos on my webview. Problems are arising when displaying video in fullscreen mode.

As I figured out, android has two ways of handling the < video > tag:

  1. On android versions <= 2.3.3, the onShowCustomView method is fired, and I can have the VideoView instance, and set listeners when the video completes, set controllers etc. So far so good.

  2. On ICS (and probably 3.0 and above), it looks like the < video > is handled in different way. When the HTML5 video is played the onShowCustomView isn't being called on normal mode - it looks like there is an internal business inside the WebView that plays the video, and all the controls that are defined in the < video > tag are shown - I can't access it in any way. Actually, if the video is played in normal mode this is OK because the controls are there and are working.

That led me to the big problem: when displaying the video in full screen mode the onShowCustomView is being called - but on ICS the "view" parameter isn't an instance of VideoView.

I managed to find out that the instance is of VideoSurfaceView, a private inner class of HTML5VideoFullScreen class. The only way we can access this inner-class is via reflection.

After looking at GrepCode for this class, I learnt that unlike VideoView, the HTML5VideoFullScreen$VideoSurfaceView doesn't hold a MediaPlayer instance that I can listen to its events or access its controls. The only thing I can do is take this VideoSurfaceView as it is and put it inside a full-screen-layout without controlling it.

Bottom line - When displaying video in full-screen, I don't know when the video ends, its controls aren't shown - this is pretty sad. I can't get the trigger for closing the full-screen.

I tried few unsuccessful workarounds:

  1. Reflection: I tried to reach the HTML5VideoFullScreen instance, which holds a MediaPlayer member, from the inner-class VideoSurfaceView. I didn't manage to get it, I'm not sure this is possible (ViewSurfaceView doesn't hold its owner's instance).

  2. Register for the video events via Javascript (onended, for example), and handle what I need back in JAVA via JavascriptInterface: I found this solution isn't reliable because while doing this I encountered another problem: the < video > tag can be nested in an . The iframe source isn't mine and I can't get its content (getElementById or getElementsByTagName[i] are nulls) - which means, I can't reach the < video > element inside the iframe.

I'm still searching for a solution, very little is written about this issue. Did anyone manage to solve it? Help would be much appreciated!

VideoView class: Here (has MediaPlayer)

HTML5VideoFullScreen$VideoSurfaceView class: Here (doesn't have MediaPlayer)

Question&Answers:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Edit 2014/10: by popular demand I'm maintaining and moving this to GitHub. Please check cprcrack/VideoEnabledWebView for the last version. Will keep this answer only for reference.

Edit 2014/01: improved example usage to include the nonVideoLayout, videoLayout, and videoLoading views, for those users requesting more example code for better understading.

Edit 2013/12: some bug fixes related to Sony Xperia devices compatibility, but which in fact affected all devices.

Edit 2013/11: after the release of Android 4.4 KitKat (API level 19) with its new Chromium webview, I had to work hard again. Several improvements were made. You should update to this new version. I release this source under WTFPL.

Edit 2013/04: after 1 week of hard work, I finally have achieved everything I needed. I think this two generic classes that I have created can solve all you problems.

VideoEnabledWebChromeClient can be used alone if you do not require the functionality that VideoEnabledWebView adds. But VideoEnabledWebView must always rely on a VideoEnabledWebChromeClient. Please read all the comments of the both classes carefully.

VideoEnabledWebChromeClient class

import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnErrorListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.webkit.WebChromeClient;
import android.widget.FrameLayout;

/**
 * This class serves as a WebChromeClient to be set to a WebView, allowing it to play video.
 * Video will play differently depending on target API level (in-line, fullscreen, or both).
 *
 * It has been tested with the following video classes:
 * - android.widget.VideoView (typically API level <11)
 * - android.webkit.HTML5VideoFullScreen$VideoSurfaceView/VideoTextureView (typically API level 11-18)
 * - com.android.org.chromium.content.browser.ContentVideoView$VideoSurfaceView (typically API level 19+)
 * 
 * Important notes:
 * - For API level 11+, android:hardwareAccelerated="true" must be set in the application manifest.
 * - The invoking activity must call VideoEnabledWebChromeClient's onBackPressed() inside of its own onBackPressed().
 * - Tested in Android API levels 8-19. Only tested on http://m.youtube.com.
 *
 * @author Cristian Perez (http://cpr.name)
 *
 */
public class VideoEnabledWebChromeClient extends WebChromeClient implements OnPreparedListener, OnCompletionListener, OnErrorListener
{
    public interface ToggledFullscreenCallback
    {
        public void toggledFullscreen(boolean fullscreen);
    }

    private View activityNonVideoView;
    private ViewGroup activityVideoView;
    private View loadingView;
    private VideoEnabledWebView webView;

    private boolean isVideoFullscreen; // Indicates if the video is being displayed using a custom view (typically full-screen)
    private FrameLayout videoViewContainer;
    private CustomViewCallback videoViewCallback;

    private ToggledFullscreenCallback toggledFullscreenCallback;

    /**
     * Never use this constructor alone.
     * This constructor allows this class to be defined as an inline inner class in which the user can override methods
     */
    @SuppressWarnings("unused")
    public VideoEnabledWebChromeClient()
    {
    }

    /**
     * Builds a video enabled WebChromeClient.
     * @param activityNonVideoView A View in the activity's layout that contains every other view that should be hidden when the video goes full-screen.
     * @param activityVideoView A ViewGroup in the activity's layout that will display the video. Typically you would like this to fill the whole layout.
     */
    @SuppressWarnings("unused")
    public VideoEnabledWebChromeClient(View activityNonVideoView, ViewGroup activityVideoView)
    {
        this.activityNonVideoView = activityNonVideoView;
        this.activityVideoView = activityVideoView;
        this.loadingView = null;
        this.webView = null;
        this.isVideoFullscreen = false;
    }

    /**
     * Builds a video enabled WebChromeClient.
     * @param activityNonVideoView A View in the activity's layout that contains every other view that should be hidden when the video goes full-screen.
     * @param activityVideoView A ViewGroup in the activity's layout that will display the video. Typically you would like this to fill the whole layout.
     * @param loadingView A View to be shown while the video is loading (typically only used in API level <11). Must be already inflated and without a parent view.
     */
    @SuppressWarnings("unused")
    public VideoEnabledWebChromeClient(View activityNonVideoView, ViewGroup activityVideoView, View loadingView)
    {
        this.activityNonVideoView = activityNonVideoView;
        this.activityVideoView = activityVideoView;
        this.loadingView = loadingView;
        this.webView = null;
        this.isVideoFullscreen = false;
    }

    /**
     * Builds a video enabled WebChromeClient.
     * @param activityNonVideoView A View in the activity's layout that contains every other view that should be hidden when the video goes full-screen.
     * @param activityVideoView A ViewGroup in the activity's layout that will display the video. Typically you would like this to fill the whole layout.
     * @param loadingView A View to be shown while the video is loading (typically only used in API level <11). Must be already inflated and without a parent view.
     * @param webView The owner VideoEnabledWebView. Passing it will enable the VideoEnabledWebChromeClient to detect the HTML5 video ended event and exit full-screen.
     * Note: The web page must only contain one video tag in order for the HTML5 video ended event to work. This could be improved if needed (see Javascript code).
     */
    public VideoEnabledWebChromeClient(View activityNonVideoView, ViewGroup activityVideoView, View loadingView, VideoEnabledWebView webView)
    {
        this.activityNonVideoView = activityNonVideoView;
        this.activityVideoView = activityVideoView;
        this.loadingView = loadingView;
        this.webView = webView;
        this.isVideoFullscreen = false;
    }

    /**
     * Indicates if the video is being displayed using a custom view (typically full-screen)
     * @return true it the video is being displayed using a custom view (typically full-screen)
     */
    public boolean isVideoFullscreen()
    {
        return isVideoFullscreen;
    }

    /**
     * Set a callback that will be fired when the video starts or finishes displaying using a custom view (typically full-screen)
     * @param callback A VideoEnabledWebChromeClient.ToggledFullscreenCallback callback
     */
    public void setOnToggledFullscreen(ToggledFullscreenCallback callback)
    {
        this.toggledFullscreenCallback = callback;
    }

    @Override
    public void onShowCustomView(View view, CustomViewCallback callback)
    {
        if (view instanceof FrameLayout)
        {
            // A video wants to be shown
            FrameLayout frameLayout = (FrameLayout) view;
            View focusedChild = frameLayout.getFocusedChild();

            // Save video related variables
            this.isVideoFullscreen = true;
            this.videoViewContainer = frameLayout;
            this.videoViewCallback = callback;

            // Hide the non-video view, add the video view, and show it
            activityNonVideoView.setVisibility(View.INVISIBLE);
            activityVideoView.addView(videoViewContainer, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
            activityVideoView.setVisibility(View.VISIBLE);

            if (focusedChild instanceof android.widget.VideoView)
            {
                // android.widget.VideoView (typically API level <11)
                android.widget.VideoView videoView = (android.widget.VideoView) focusedChild;

                // Handle all the required events
                videoView.setOnPreparedListener(this);
                videoView.setOnCompletionListener(this);
                videoView.setOnErrorListener(this);
            }
            else
            {
                // Other classes, including:
                // - android.webkit.HTML5VideoFullScreen$VideoSurfaceView, which inherits from android.view.SurfaceView (typically API level 11-18)
                // - android.webkit.HTML5VideoFullScreen$VideoTextureView, which inherits from android.view.TextureView (typically API level 11-18)
                // - com.android.org.chromium.content.browser.ContentVideoView$VideoSurfaceView, which inherits from android.view.SurfaceView (typically API level 19+)

                // Handle HTML5 video ended event only if the class is a SurfaceView
                // Test case: TextureView of Sony Xperia T API level 16 doesn't work fullscreen when loading the javascript below
                if (webView != null && webView.getSettings().getJavaScriptEnabled() && focusedChild instanceof SurfaceView)
                {
                    // Run javascript code that detects the video end and notifies the Javascript interface
                    String js = "javascript:";
                    js += "var _ytrp_html5_video_last;";
                    js += "var _ytrp_html5_video = document.getElementsByTagName('video')[0];";
                    js += "if (_ytrp_html5_video != undefined && _ytrp_html5_video != _ytrp_html5_video_last) {";
                    {
                        js += "_ytrp_html5_video_last = _ytrp_html5_video;";
                        js += "function _ytrp_html5_video_ended() {";
                        {
                            js += "_VideoEnabledWebView.notifyVideoEnd();"; // Must match Javascript interface name and method of VideoEnableWebView
                        }
                        js += "}";
                        js += "_ytrp_html5_video.addEventListener('ended', _ytrp_html5_video_ended);";
                    }
                    js += "}";
                    webView.loadUrl(js);
                }
            }

            // Notify full-screen change
            if (toggledFullscreenCallback != null)
            {
                toggledFullscreenCallback.toggledFullscreen(true);
            }
        }
    }

    @Override @SuppressWarnings("deprecation")
    public void onShowCustomView(View view, int requestedOrientation, CustomViewCallback callback) // Available in API level 14+, deprecated in API level 18+
    {
        onShowCustomView(view, callback);
    }

    @Override
    public void onHideCustomView()
    {
        // This method should be manually called on video end in all cases because it's not always called automatically.
        // This method must be manually called on back key press (from this class' onBackPressed() method).

        if (isVideoFullscreen)
        {
            // Hide the video view, remove it, and show the non-video view
            activityVideoView.setVisibility(View.INVISIBLE);
            activityVideoView.removeView(videoViewContainer);
            activityNonVideoView.setVisibility(View.VISIBLE);

            // Call back (only in API level <19, because in API level 19+ with chromium webview it crashes)
            if (videoViewCallback != null && !videoVi

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...