videoview 可以播放存储在内部存储器上的视频吗? [英] Can a videoview play a video stored on internal storage?

问题描述

我正在努力让我的用户能够使用外部或内部存储.我正在显示图像和视频(具有科学性质).将媒体存储在 SD 卡上时，一切正常.但是当我在内部存储媒体时，只会显示图像.无论我尝试什么，在尝试加载和显示存储在 applicationcontext.getFilesDir() 下的媒体时都会遇到各种错误.

将视频视图的内容设置为这样的文件有什么技巧吗?

ContentResolver 可以帮助我吗?

在相关说明中，假设存在外部存储是否被认为是不好的形式?

提前致谢，

席德

以下是一个因无法播放视频.抱歉，无法播放此视频"而失败的版本.但我还有很多其他的失败模式.我可以将内部视频复制到临时存储(外部)并播放它，所以这个复制到内部确实创建了一个有效的电影.只有当我尝试直接从内部存储播放时才会失败.

videoFile = new File(this.getFilesDir() + File.separator + "test.mp4");InputStream data = res.openRawResource(R.raw.movi​​egood);尝试 {OutputStream myOutputStream = new FileOutputStream(videoFile);字节[]缓冲区=新字节[8192]；整数长度；while ( (length = data.read(buffer)) > 0 ) {myOutputStream.write(buffer);}//关闭流myOutputStream.flush();myOutputStream.close();数据关闭()；} catch (FileNotFoundException e) {//TODO 自动生成的 catch 块e.printStackTrace();} catch (IOException e) {//TODO 自动生成的 catch 块e.printStackTrace();}vview.setKeepScreenOn(true);vview.setVideoPath(videoFile.getAbsolutePath());vview.start();

解决方案

MediaPlayer 要求正在播放的文件具有全局可读权限.可以在 adb shell 中使用以下命令查看文件的权限:

ls -al/data/data/com.mypackage/myfile

您可能会看到-rw------"，这意味着只有所有者(您的应用，而不是 MediaPlayer)具有读/写权限.

注意:您的手机必须root才能使用ls命令而不指定文件(在内存中).

如果您的手机已root，您可以使用以下命令在adb shell中添加全局读取权限:

chmod o+r/data/data/com.mypackage/myfile

如果您需要以编程方式修改这些权限(需要root手机！)，您可以在您的应用代码中使用以下命令:

Runtime.getRuntime().exec("chmod o+r/data/data/com.mypackage/myfile");

这基本上是一个 linux 命令.有关 chmod 的更多信息，请参阅 https://help.ubuntu.com/community/FilePermissions.>

找到另一种简单的方法 here(对于没有root手机的人很有用).由于应用程序拥有该文件，它可以创建一个文件描述符并将其传递给 mediaPlayer.setDataSource():

FileInputStream fileInputStream = new FileInputStream("/data/data/com.mypackage/myfile");mediaPlayer.setDataSource(fileInputStream.getFD());

这种方法完全避免了权限问题.

I'm trying to provide my users with the ability to use either external or internal storage. I'm displaying both images and videos (of a scientific nature). When storing the media on the SD card, all is fine. But when I store the media internally, only the images will display. No matter what I try I get various errors when trying to load and display the media stored under the applicationcontext.getFilesDir().

Is there a trick to setting a videoview's content to such a file?

Can a ContentResolver help me?

On a related note, is it considered bad form to assume that external storage exists?

Thanks in advance,

Sid

Below is one version that fails with "Cannot play video. Sorry, this video cannot be played". But I have many other modes of failure. I can copy the internal video to temp storage (external) and play it, so this copy to internal does indeed create a valid movie. It only fails when I try to play it directly from the internal storage.

videoFile = new File(this.getFilesDir() + File.separator + "test.mp4");


InputStream data = res.openRawResource(R.raw.moviegood);


try {
    OutputStream myOutputStream = new FileOutputStream(videoFile);


    byte[] buffer = new byte[8192];
    int length;
    while ( (length = data.read(buffer)) > 0 ) {
        myOutputStream.write(buffer);
    }

    //Close the streams
    myOutputStream.flush();
    myOutputStream.close();
    data.close();
} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}




vview.setKeepScreenOn(true);
vview.setVideoPath(videoFile.getAbsolutePath());
vview.start();

解决方案

MediaPlayer requires that the file being played has world-readable permissions. You can view the permissions of the file with the following command in adb shell:

ls -al /data/data/com.mypackage/myfile

You will probably see "-rw------", which means that only the owner (your app, not MediaPlayer) has read/write permissions.

Note: Your phone must be rooted in order to use the ls command without specifying the file (in the internal memory).

If your phone is rooted, you can add world-read permissions in adb shell with the following command:

chmod o+r /data/data/com.mypackage/myfile

If you need to modify these permissions programmatically (requires rooted phone!), you can use the following command in your app code:

Runtime.getRuntime().exec("chmod o+r /data/data/com.mypackage/myfile");

Which is basically a linux command. See https://help.ubuntu.com/community/FilePermissions for more on chmod.

EDIT: Found another simple approach here (useful for those without rooted phones). Since the application owns the file, it can create a file descriptor and pass that to mediaPlayer.setDataSource():

FileInputStream fileInputStream = new FileInputStream("/data/data/com.mypackage/myfile");
mediaPlayer.setDataSource(fileInputStream.getFD());

This approach avoids the permission issue completely.

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