Android: improve error handling for document providers.

Now some operations in document providers may throw a RuntimeException
in case of error. The main activity is ready to catch them and show an
error message.

Change-Id: Iad7249dbdc06b2a0890d5435ad65284b728e9707

android/experimental/LOAndroid3/src/java/org/libreoffice/storage/IDocumentProvider.java

@@ -21,6 +21,7 @@ public interface IDocumentProvider {
      * Provides the content root element for the Document Provider.
      *
      * @return Content root element.
+     * @throws RuntimeException in case of error.
      */
     IFile getRootDirectory();
 
@@ -31,6 +32,7 @@ public interface IDocumentProvider {
      *            URI pointing to some content object that has been previously
      *            retrieved with IFile.getUri().
      * @return IFile object pointing to the content represented by uri.
+     * @throws RuntimeException in case of error.
      */
     IFile createFromUri(URI uri);
 

android/experimental/LOAndroid3/src/java/org/libreoffice/storage/IFile.java

@@ -71,6 +71,7 @@ public interface IFile {
      *
      * @return list of files contained by this directory, or an empty list if
      *         this is not a directory.
+     * @throws RuntimeException in case of error.
      */
     List<IFile> listFiles();
 
@@ -82,6 +83,7 @@ public interface IFile {
      *            the filter to match names against.
      * @return filtered list of files contained by this directory, or an empty
      *         list if this is not a directory.
+     * @throws RuntimeException in case of error.
      */
     List<IFile> listFiles(FileFilter filter);
 
@@ -97,6 +99,7 @@ public interface IFile {
      * for a directory is not defined.
      *
      * @return local file containing the document wrapped by this object.
+     * @throws RuntimeException in case of error.
      */
     File getDocument();
 }

android/experimental/LOAndroid3/src/java/org/libreoffice/ui/LibreOfficeUIActivity.java

@@ -64,6 +64,7 @@ import android.widget.ListAdapter;
 import android.widget.ListView;
 import android.widget.SpinnerAdapter;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import java.net.URI;
 import java.net.URISyntaxException;
@@ -232,11 +233,24 @@ public class LibreOfficeUIActivity extends LOAbout implements ActionBar.OnNaviga
                 // switch document provider:
                 // these operations may imply network access and must be run in
                 // a different thread
+                try {
                     documentProvider = provider[0];
                     homeDirectory = documentProvider.getRootDirectory();
                     currentDirectory = homeDirectory;
                     filePaths = currentDirectory.listFiles(FileUtilities
                             .getFileFilter(filterMode));
+                }
+                catch (final RuntimeException e) {
+                    final Activity activity = LibreOfficeUIActivity.this;
+                    activity.runOnUiThread(new Runnable() {
+                        @Override
+                        public void run() {
+                            Toast.makeText(activity, e.getMessage(),
+                                    Toast.LENGTH_SHORT).show();
+                        }
+                    });
+                    Log.e(tag, e.getMessage(), e.getCause());
+                }
                 return null;
             }
 
@@ -258,8 +272,21 @@ public class LibreOfficeUIActivity extends LOAbout implements ActionBar.OnNaviga
                 // this operation may imply network access and must be run in
                 // a different thread
                 currentDirectory = dir[0];
+                try {
                     filePaths = currentDirectory.listFiles(FileUtilities
                             .getFileFilter(filterMode));
+                }
+                catch (final RuntimeException e) {
+                    final Activity activity = LibreOfficeUIActivity.this;
+                    activity.runOnUiThread(new Runnable() {
+                        @Override
+                        public void run() {
+                            Toast.makeText(activity, e.getMessage(),
+                                    Toast.LENGTH_SHORT).show();
+                        }
+                    });
+                    Log.e(tag, e.getMessage(), e.getCause());
+                }
                 return null;
             }
 
@@ -276,11 +303,26 @@ public class LibreOfficeUIActivity extends LOAbout implements ActionBar.OnNaviga
             protected File doInBackground(IFile... document) {
                 // this operation may imply network access and must be run in
                 // a different thread
+                try {
                     return document[0].getDocument();
                 }
+                catch (final RuntimeException e) {
+                    final Activity activity = LibreOfficeUIActivity.this;
+                    activity.runOnUiThread(new Runnable() {
+                        @Override
+                        public void run() {
+                            Toast.makeText(activity, e.getMessage(),
+                                    Toast.LENGTH_SHORT).show();
+                        }
+                    });
+                    Log.e(tag, e.getMessage(), e.getCause());
+                    return null;
+                }
+            }
 
             @Override
             protected void onPostExecute(File file) {
+                if (file != null) {
                     Intent i = new Intent(Intent.ACTION_VIEW, Uri.fromFile(file));
                     String packageName = getApplicationContext().getPackageName();
                     ComponentName componentName = new ComponentName(packageName,
@@ -288,6 +330,7 @@ public class LibreOfficeUIActivity extends LOAbout implements ActionBar.OnNaviga
                     i.setComponent(componentName);
                     startActivity(i);
                 }
+            }
         }.execute(document);
     }