Question

There’s something magic going on in one of my library projects. While layouts (res/layout) are fetched from the library project itself, files within the assets folder are fetched from the calling project (not the library project).

I’m currently building a help activity in a library project. The calling project gives a filename to the activity in the library project. The files are stored in the calling project – not in the library project.

When using the AssetsManager in the library project it uses the files from the calling project – not from the assets folder of the library project.

Is this correct behaviour?

Here’s the stripped down calling Activity in the root project:

// Calling Project
package aa.bb.aa;

public class MyListActivity extends ListActivity {

    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        setContentView(R.layout.mylistactivity); // <--- Stored in resources of the calling project
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem menuItem) {
        if (menuItem.getItemId() == R.id.men_help) {
            Intent intent = new Intent(this, aa.bb.bb.MyFileBrowser.class);
            intent.putExtra(MyConstants.FILE, "mylistactivity.html"); // <-- Stored in assets of the calling project
            startActivityForResult(intent, MyConstants.DIALOG_HELP);
            return true;
        }

        return super.onOptionsItemSelected(menuItem);
    }
}

And here’s the Activity in the Library project. I thought that assets are fetched from here and not from the calling Activity/Project:

// Library project
package aa.bb.bb;

    public class MyFileBrowser extends Activity {

        @Override
        public void onCreate(Bundle bundle) {
            super.onCreate(bundle);

            setContentView(R.layout.myfilebrowser); // <-- Stored in resources of the library project

            webView = (WebView) findViewById(R.id.browser);

            Locale locale = Locale.getDefault();
            String localeLanguage = (locale.getLanguage() != null) ? locale.getLanguage() : "en";

            Bundle bundleExtras = getIntent().getExtras();
            if (bundleExtras != null) {
                String file = bundleExtras.getString(MyConstants.FILE);
                if (!StringUtils.isEmpty(file)) {
                    String filename = "help-" + localeLanguage + File.separator + file;

                    AssetManager assetManager = getAssets();
                    InputStream inputStream = null;
                    try {
                        inputStream = assetManager.open(filename);
                    } catch (IOException ioException) {
                        filename = "help-en" + File.separator + file;
                    } finally {
                        try {
                            if (inputStream != null) {
                                inputStream.close();
                            }
                        } catch (IOException ioException) {
                        }
                    }

                    webView.loadUrl("file:///android_asset" + File.separator + filename); // <-- Uses file in assets of calling project - not library project
                }
            }
        }
    }

Answer 1

Found the answer. assets are always used from the referencing project. A library project can’t hold assets. I found it on this page:

Library Projects

Here’s the part of the doc that does describe this:

The tools do not support the use of raw asset files (saved in the
assets/ directory) in a library project. Any asset resources used by
an application must be stored in the assets/ directory of the
application project itself. However, resource files saved in the res/
directory are supported.