Trying to send a pdf using cwac provider

Question

I can't quite get cwac to work, and looking at the demo code hasn't helped. I'm simply trying to export a pdf through a share intent. Currently the output is a "Can't attach empty file" error. But the file does exist, and I can't tell if the problem is with the file name, location, or cwac provider usage.

Here is how I've set up the provider.

        <provider
        android:name="com.commonsware.cwac.provider.StreamProvider"
        android:authorities="com.anothergamedesigner.CatVimeoTest.provider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="com.commonsware.cwac.provider.STREAM_PROVIDER_PATHS"
            android:resource="@xml/file_paths"/>
    </provider>

This is my xml resource the provider is using. I set path to "" because I don't have any subdirectories. I don't know if those are required, but ideally I don't want to have to switch up my code elsewhere for the file restructure necessary to put the files in subdirectories. Although, if that's the problem, I suppose I could, but I don't see why the root shouldn't work.

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <asset name="assets" path=""/>
</paths>

Here is my PDFActivity (extends AppCompatActivity):

Variables:

private String pdfName //set in onCreate; ex. "This is my.pdf"

private static final String AUTHORITY = "com.anothergamedesigner.CatVimeoTest";
private static final Uri PROVIDER = Uri.parse("content://"+AUTHORITY);
private static final String ASSET_PATHS ="assets/";

Methods definitions:

private Intent getOpenPDFShareIntent(String name){
    Intent shareIntent = new Intent(android.content.Intent.ACTION_SEND);
    shareIntent.setType("application/pdf");

    shareIntent.putExtra(android.content.Intent.EXTRA_EMAIL, new String[] {""});
    shareIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, getResources().getString(R.string.default_share_subject));
    shareIntent.putExtra(android.content.Intent.EXTRA_TEXT, getResources().getString(R.string.default_share_text));

    shareIntent.putExtra(Intent.EXTRA_STREAM, getURI());
    shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    shareIntent.setType("text/plain");
    return shareIntent;
}

private Uri getURI(){
    String path = ASSET_PATHS + pdfName;
    return(PROVIDER
            .buildUpon()
            .appendPath(StreamProvider.getUriPrefix(AUTHORITY))
            .appendPath(path)
            .build());

}

In getURI(), an example return for System.out.println(path) is: "assets/my.pdf"

The code runs via a menu button that on selection:

Intent shareIntent = getOpenPDFShareIntent(pdfName);
StartActivity(Intent.createChooser(shareIntent, getResources().getString(R.string.contact_send_mail));

EDIT: Attempting to remove null URIPrefix:

    private Uri getURI(){
    //String path = ASSET_PATHS + pdfName;

    if(StreamProvider.getUriPrefix(AUTHORITY) != null){
        return(PROVIDER
                .buildUpon()
                .appendPath(StreamProvider.getUriPrefix(AUTHORITY))
                .appendPath(ASSET_PATHS)
                .appendPath(pdfName)
                .build());
    } else{
        return(PROVIDER
                .buildUpon()
                .appendPath(ASSET_PATHS)
                .appendPath(pdfName)
                .build());
    }
}

EDIT 2 - Testing with DocumentFile:

I used these new methods from another SO answer and altered it to return the file.

private File CopyReadAssets()
{
    AssetManager assetManager = getAssets();

    InputStream in = null;
    OutputStream out = null;
    File file = new File(getFilesDir(), "my.pdf");
    try
    {
        in = assetManager.open("my.pdf");
        out = openFileOutput(file.getName(), Context.MODE_WORLD_READABLE);

        copyFile(in, out);
        in.close();
        in = null;
        out.flush();
        out.close();
        out = null;
    } catch (Exception e)
    {
        Log.e("tag", e.getMessage());
    }

    return file;
}

private void copyFile(InputStream in, OutputStream out) throws IOException
{
    byte[] buffer = new byte[1024];
    int read;
    while ((read = in.read(buffer)) != -1)
    {
        out.write(buffer, 0, read);
    }
}

Then I tested using:

DocumentFile aFile = DocumentFile.fromFile(CopyReadAssets());
DocumentFile file = DocumentFile.fromSingleUri(this, getURI());
System.out.println(aFile.getName());
System.out.println(aFile.length());
System.out.println(file.getName());
System.out.println(file.length());

It returns "my.pdf" and "33528" for aFile and "my.pdf" and "FileNotFoundException" for file.

Answer 1

content://com.anothergamedesigner.CatVimeoTest/null/assets%2FCEGA%20OnBoard%20Su‌​pport%201.6.compressed.pdf

There are two problems here that I can see.

First, StreamProvider.getUriPrefix(AUTHORITY) is returning null. I don't know why, as you do not appear to be subclassing StreamProvider. That being said, you should check for null and skip that appendPath() statement if it is null.

Second, rather than ASSET_PATHS + pdfName, use two appendPath() statements. This should prevent the / from being converted into %2F.

Note that I have not tried files with spaces in the name, or anything else that has to get escaped, as you have in your filename. It's possible that there are bugs related to this. If changing the two items above do not help, try renaming the PDF temporarily to something simple. If that then works, I have a bug that I'll need to fix.

Answer 2

FINAL CODE

The problem is seems was with ASSET_PATHS. Appending the pdfName to "assets" proved to be problematic for some reason. Because of this I chose to change ASSET_PATHS from a final and then set it in the onCreate method. This would be one way to do it, or you could hard code in the different pdfs such as in the demo project.

public class PDFViewActivity extends AppCompatActivity {

private String pdfName;
...

private static final String AUTHORITY = "com.your.provider";
private static final Uri PROVIDER = Uri.parse("content://"+AUTHORITY);
private static String ASSET_PATHS;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Bundle extras = getIntent().getExtras();
    pdfName = extras.getString("pdfName");
    ...

    ASSET_PATHS = "assets/" + pdfName;

    // Place an PDFViewFragment as our content pane
    PDFViewFragment f = new PDFViewFragment();
    getSupportFragmentManager().beginTransaction().add(android.R.id.content, f).commit();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_pdf, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
        case R.id.menu_button_share:
            Intent shareIntent = getOpenPDFShareIntent();
            startActivity(Intent.createChooser(shareIntent, "Send Email"));
            return true;
        ...
        default:
            return super.onOptionsItemSelected(item);
    }
}

private Intent getOpenPDFShareIntent(){
    Intent shareIntent = new Intent(Intent.ACTION_SEND);
    shareIntent.setType("application/pdf");

    shareIntent.putExtra(android.content.Intent.EXTRA_EMAIL, new String[] {""});
    shareIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, getResources().getString(R.string.default_share_subject));
    shareIntent.putExtra(android.content.Intent.EXTRA_TEXT, getResources().getString(R.string.default_share_text));
    shareIntent.putExtra(Intent.EXTRA_STREAM, getURI());
    shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    shareIntent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);

    return shareIntent;
}

private Uri getURI(){
    return(PROVIDER
            .buildUpon()
            .appendPath(StreamProvider.getUriPrefix(AUTHORITY))
            .appendPath(ASSET_PATHS)
            .build());
}

}