android share audio file from assets folder

问题

I can't share audio file from assets. Each app says that it can't send the file.

Method for converting inputstream to temporary file

    public File getFile(String Prefix, String Suffix) throws IOException {

    File tempFile = File.createTempFile(Prefix, Suffix);
    AssetFileDescriptor tempafd = FXActivity.getInstance().getAssets().openFd(filepath);
    tempFile.deleteOnExit();
    FileOutputStream out = new FileOutputStream(tempFile);
    IOUtils.copy(tempafd.createInputStream(), out);


    return tempFile;
}

Sharing file

        item2.setOnAction(n ->{
            try {
                Uri uri = Uri.fromFile(tekst.getFile(tekst.getFilename(), ".mp3"));
                Intent share = new Intent();
                share.setType("audio/*");
                share.setAction(Intent.ACTION_SEND);
                share.putExtra(Intent.EXTRA_STREAM, uri);
                FXActivity.getInstance().startActivity(share);
            } catch (IOException ex) {
                Logger.getLogger(MainCategoryCreator.class.getName()).log(Level.SEVERE, null, ex);
            }

        });

回答1:

Just as it happens, I struggled with almost an identical problem: I needed to share a video file. The problem is: There is now way to share an internal file. Never. You either need a ContentProvider, or since it's a bit simpler with it, it's extension FileProvider.

First: you need to update you AndroidManifest.xml:

<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="my.package.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

This needs to be added into the <application>tag.

Then you need the XML file file_paths.xml in the Android sub-directory res/xml/

It should something like this:

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path name="objects" path="objects/"/>
</paths>

And to finally trigger it, I needed to call it like this:

Uri uri = Uri.parse("content://my.package.fileprovider/" + fn); 
Intent intent = new Intent(Intent.ACTION_VIEW, uri); // or parse uri each time
intent.setDataAndType(uri, "video/*"); // all video type == * - alternative: mp4, ...
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_GRANT_READ_URI_PERMISSION);
List<ResolveInfo> resInfoList = FXActivity.getInstance().getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
for (ResolveInfo resolveInfo : resInfoList) {
    String packageName = resolveInfo.activityInfo.packageName;
    FXActivity.getInstance().grantUriPermission(packageName, uri, Intent.FLAG_GRANT_READ_URI_PERMISSION);
}
FXActivity.getInstance().startActivity(intent);

But what I needed to do prior to be able to use it like this: I needed to copy all assets to the private files dir, because the FileProvider itself has no option to access your assets (I guess you could achieve this with a custom ContentProvider, but I found way to complicated and didn't have that much time).

See this Android Developer reference on FileProvider for mor information.

My simple solution for this looks like this:

public boolean copyAssetsToStorage() throws NativeServiceException {
    try {
        String[] assets = getContext().getAssets().list(DIR_NAME);
        if (assets == null || assets.length == 0) {
            LOG.warning("No assets found in '" + DIR_NAME + "'!");
            return false;
        }
        File filesDir = getContext().getFilesDir();
        File targetDir = new File(filesDir, DIR_NAME);
        if (!targetDir.isDirectory()) {
            boolean b = targetDir.mkdir();
            if (!b) {
                LOG.warning("could not create private directory with the name '" + DIR_NAME + "'!");
                return false;
            }
        }
        for (String asset : assets) {
            File targetFile = new File(targetDir, asset);
            if (targetFile.isFile()) {
                LOG.info("Asset " + asset + " already present. Nothing to do.");
                continue;
            } else {
                LOG.info("Copying asset " + asset + " to private files.");
            }
            InputStream is = null;
            OutputStream os = null;
            try {
                is = getContext().getAssets().open(DIR_NAME + "/" + asset);
                os = new FileOutputStream(targetFile.getAbsolutePath());
                byte[] buff = new byte[1024];
                int len;
                while ((len = is.read(buff)) > 0)
                    os.write(buff, 0, len);
            } catch (IOException e) {
                LOG.log(Level.SEVERE, e.getMessage(), e);
                continue;
            }
            if (os != null) {
                os.flush();
                os.close();
            }
            if (is != null)
                is.close();
        }
        return true;
    } catch (IOException e) {
        LOG.log(Level.SEVERE, e.getMessage(), e);
        return false;
    }
}

As you can see, I only support a flat hierarchy for now...

This at least did the trick for me.

Regards, Daniel

---

ADDIDIONAL QUESTION: Why are you sending an Intent and not implement a simple JavaFX audio player control? This is what I did prior to the Video stuff.

来源：https://stackoverflow.com/questions/40671626/android-share-audio-file-from-assets-folder