Android中VideoView音视频开发的实现_Java

本篇文章主要介绍下android 中的videoview.

1: videoview简介

videoview是一个用于播放视频的视图组件，可以方便地在应用程序中播放本地或网络上的视频文件。

videoview可以直接在布局文件中使用，也可以在代码中动态创建。

它封装了mediaplayer和surfaceview，提供了简单的接口来控制视频的播放和显示。

它提供了一系列方法来控制视频的播放、暂停、停止等操作，并且支持全屏播放和视频控制器的显示。

videoview播放视频非常简单，只需要指定视频的url或本地路径.

2: 使用

以下是videoview的简单使用:

2.1 布局

在xml布局文件中添加videoview组件.

<videoview
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_constrainttop_totopof="parent"
    app:layout_constraintstart_tostartof="parent"
    android:id="@+id/videoview"
    />

2.2 设置视频源

代码如下:

videoview = findviewbyid(r.id.videoview);
videoview.setvideopath("sdcard/test.mp4");

除了setvideopath外,我们还可以调用:

setvideouri(uri uri)
setvideouri(uri uri, map<string, string> headers)

当然不管是setvideopath或者setvideouri实际都是执行的setvideouri(uri uri, map<string, string> headers).

源码如下:

/**
 * sets video path.
 *
 * @param path the path of the video.
 */
public void setvideopath(string path) {
    setvideouri(uri.parse(path));
}

/**
 * sets video uri.
 *
 * @param uri the uri of the video.
 */
public void setvideouri(uri uri) {
    setvideouri(uri, null);
}

2.3 播放视频

videoview.start();

我们可以看下start()的源码:

@override
public void start() {
    if (isinplaybackstate()) {
        mmediaplayer.start();
        mcurrentstate = state_playing;
    }
    mtargetstate = state_playing;
}

可以看到实际上调用mmediaplayer.start();另外设置了当前的状态为state_playing.

这里直接调用了mmediaplayer.start();那mmediaplayer是什么时机初始化的呢?

查看源码可以看到:

private void openvideo() {
    if (muri == null || msurfaceholder == null) {
        // not ready for playback just yet, will try again later
        return;
    }
    // we shouldn't clear the target state, because somebody might have
    // called start() previously
    release(false);

    if (maudiofocustype != audiomanager.audiofocus_none) {
        // todo this should have a focus listener
        maudiomanager.requestaudiofocus(null, maudioattributes, maudiofocustype, 0 /*flags*/);
    }

    try {
        mmediaplayer = new mediaplayer();
        // todo: create subtitlecontroller in mediaplayer, but we need
        // a context for the subtitle renderers
        final context context = getcontext();
        final subtitlecontroller controller = new subtitlecontroller(
                context, mmediaplayer.getmediatimeprovider(), mmediaplayer);
        controller.registerrenderer(new webvttrenderer(context));
        controller.registerrenderer(new ttmlrenderer(context));
        controller.registerrenderer(new cea708captionrenderer(context));
        controller.registerrenderer(new closedcaptionrenderer(context));
        mmediaplayer.setsubtitleanchor(controller, this);

        if (maudiosession != 0) {
            mmediaplayer.setaudiosessionid(maudiosession);
        } else {
            maudiosession = mmediaplayer.getaudiosessionid();
        }
        mmediaplayer.setonpreparedlistener(mpreparedlistener);
        mmediaplayer.setonvideosizechangedlistener(msizechangedlistener);
        mmediaplayer.setoncompletionlistener(mcompletionlistener);
        mmediaplayer.setonerrorlistener(merrorlistener);
        mmediaplayer.setoninfolistener(minfolistener);
        mmediaplayer.setonbufferingupdatelistener(mbufferingupdatelistener);
        mcurrentbufferpercentage = 0;
        mmediaplayer.setdatasource(mcontext, muri, mheaders);
        mmediaplayer.setdisplay(msurfaceholder);
        mmediaplayer.setaudioattributes(maudioattributes);
        mmediaplayer.setscreenonwhileplaying(true);
        mmediaplayer.prepareasync();

        for (pair<inputstream, mediaformat> pending: mpendingsubtitletracks) {
            try {
                mmediaplayer.addsubtitlesource(pending.first, pending.second);
            } catch (illegalstateexception e) {
                minfolistener.oninfo(
                        mmediaplayer, mediaplayer.media_info_unsupported_subtitle, 0);
            }
        }

        // we don't set the target state here either, but preserve the
        // target state that was there before.
        mcurrentstate = state_preparing;
        attachmediacontroller();
    } catch (ioexception ex) {
        log.w(tag, "unable to open content: " + muri, ex);
        mcurrentstate = state_error;
        mtargetstate = state_error;
        merrorlistener.onerror(mmediaplayer, mediaplayer.media_error_unknown, 0);
        return;
    } catch (illegalargumentexception ex) {
        log.w(tag, "unable to open content: " + muri, ex);
        mcurrentstate = state_error;
        mtargetstate = state_error;
        merrorlistener.onerror(mmediaplayer, mediaplayer.media_error_unknown, 0);
        return;
    } finally {
        mpendingsubtitletracks.clear();
    }
}

可以看到openvideo()

release()方法释放正在播放的视频.
初始化mmediaplayer,传入uri,设置状态 state_preparing。
attachmediacontroller()绑定mediaplayer与videoview。

最后openvideo()则是在setvideouri(uri uri, map<string, string> headers)内调用。

这样其实已经可以播放指定的视频了。

下面的方法可选。

2.4 mediacontroller控制器

mediacontroller是一个用于控制媒体播放器的视图组件。

mediacontroller的使用步骤如下：

创建一个mediacontroller对象：mediacontroller mediacontroller = new mediacontroller(context);
将mediacontroller与媒体播放器组件关联：mediacontroller.setmediaplayer(mediaplayer);
将mediacontroller添加到布局中：layout.addview(mediacontroller);

videoview.setmediacontroller(new mediacontroller(this));
videoview.start().

直接调用setmediacontroller,运行后我们可以看到与之前直接调用start()的区别就是多了个控制器的显示。其中包含一组常用的媒体控制按钮，如播放/暂停、快进/快退、前进/后退等，并且可以与mediaplayer或videoview等媒体播放器组件进行关联.

我们可以看下源码：

public void setmediacontroller(mediacontroller controller) {
    if (mmediacontroller != null) {
        mmediacontroller.hide();
    }
    mmediacontroller = controller;
    attachmediacontroller();
}

可以看到做的操作如下：