android: Use system file picker to create new docs

Similar to the way that existing documents can be
opened from within the Android Viewer app
using the system file picker by using
'Intent.ACTION_OPEN_DOCUMENT', use the system file picker
via 'Intent.ACTION_CREATE_DOCUMENT' to create new docs
as well, instead of providing a custom dialog to
insert a file name.

As described at [1], this allows to save files
in locations supported by any existing
DocumentsProvider (e.g. a Nextcloud share,
if the Nextcloud app is installed and set up),
not just locally.

This also allows to further unify the handling in
LOMainActivity. Just like for the cases where an
existing document is opened using the system file
picker or a document is passed from a third-party app,
the document URI is now set in the Intent, a
temporary file is used and writing back to the
actual URI happens on save.

Drop LibreOfficeMainActivity's method 'showSaveStatusMessage',
which was only meant to be used when a new file was created, but
was called from the more generic 'LOKitTileProvider::saveDocumentAs'.
Change that to show a more general error message when saving fails.
Since the actual file is now created by the DocumentsProvider,
LOKitTileProvider only operates on the temporary copy anyway.

Side note: With this change in place, overwriting
existing files also no longer just happens silently,
as used to be the case when typing the name of an existing
file in the custom dialog for creating new files
earlier.

Since 'Intent.ACTION_OPEN_DOCUMENT' was introduced
in SDK version 19 (Android 4.4), restrict creating
new docs to corresponding devices.

[1] https://developer.android.com/training/data-storage/shared/documents-files

Change-Id: I8932cb892ca8ac97a04d15cbd1540d0ee68350da
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/113408
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
(cherry picked from commit 4b8540911bc8fabee0729b31780a1ba8b4663121)

1 files changed, 31 insertions, 44 deletions

diff --git a/android/source/src/java/org/libreoffice/LibreOfficeMainActivity.java b/android/source/src/java/org/libreoffice/LibreOfficeMainActivity.java
index 6db06d155322..a070c292009c 100644
--- a/android/source/src/java/org/libreoffice/LibreOfficeMainActivity.java
+++ b/android/source/src/java/org/libreoffice/LibreOfficeMainActivity.java
@@ -58,6 +58,7 @@ import java.nio.channels.FileChannel;
 import java.nio.channels.ReadableByteChannel;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.UUID;
 
 /**
  * Main activity of the LibreOffice App. It is started in the UI thread.
@@ -127,7 +128,7 @@ public class LibreOfficeMainActivity extends AppCompatActivity implements Settin
     private boolean isSearchToolbarOpen = false;
     private static boolean isDocumentChanged = false;
     private boolean isUNOCommandsToolbarOpen = false;
-    public boolean isNewDocument = false;
+    private boolean isNewDocument = false;
     private long lastModified = 0;
 
     @Override
@@ -180,31 +181,35 @@ public class LibreOfficeMainActivity extends AppCompatActivity implements Settin
 
         mbISReadOnlyMode = !isExperimentalMode();
 
-        if (getIntent().getStringExtra(LibreOfficeUIActivity.NEW_DOC_TYPE_KEY) != null) {
-            // New document type string is not null, meaning we want to open a new document
-            String newDocumentType = getIntent().getStringExtra(LibreOfficeUIActivity.NEW_DOC_TYPE_KEY);
-            String newFilePath = getIntent().getStringExtra(LibreOfficeUIActivity.NEW_FILE_PATH_KEY);
-
-            // Load the new document
-            loadNewDocument(newFilePath, newDocumentType);
-        } else if (getIntent().getData() != null) {
+        if (getIntent().getData() != null) {
             if (getIntent().getData().getScheme().equals(ContentResolver.SCHEME_CONTENT)) {
-                if (copyFileToTemp() && mTempFile != null) {
+                final boolean isReadOnlyDoc;
+                if (getIntent().getStringExtra(LibreOfficeUIActivity.NEW_DOC_TYPE_KEY) != null) {
+                    // New document type string is not null, meaning we want to open a new document
+                    String newDocumentType = getIntent().getStringExtra(LibreOfficeUIActivity.NEW_DOC_TYPE_KEY);
+                    // create a temporary local file, will be copied to the actual URI when saving
+                    loadNewDocument(newDocumentType);
                     mInputFile = mTempFile;
-                    boolean isReadOnlyDoc = (getIntent().getFlags() & Intent.FLAG_GRANT_WRITE_URI_PERMISSION) == 0;
-                    mbISReadOnlyMode = !isExperimentalMode()  || isReadOnlyDoc;
-                    Log.d(LOGTAG, "SCHEME_CONTENT: getPath(): " + getIntent().getData().getPath());
-
-                    String displayName = extractDisplayNameFromIntent();
-                    if (displayName.isEmpty()) {
-                        // fall back to using temp file name
-                        displayName = mInputFile.getName();
-                    }
-                    toolbarTop.setTitle(displayName);
+                    isReadOnlyDoc = false;
+                } else if (copyFileToTemp() && mTempFile != null) {
+                    mInputFile = mTempFile;
+                    isReadOnlyDoc = (getIntent().getFlags() & Intent.FLAG_GRANT_WRITE_URI_PERMISSION) == 0;
                 } else {
                     // TODO: can't open the file
                     Log.e(LOGTAG, "couldn't create temporary file from " + getIntent().getData());
+                    return;
+                }
+
+                mbISReadOnlyMode = !isExperimentalMode()  || isReadOnlyDoc;
+                Log.d(LOGTAG, "SCHEME_CONTENT: getPath(): " + getIntent().getData().getPath());
+
+                String displayName = extractDisplayNameFromIntent();
+                if (displayName.isEmpty()) {
+                    // fall back to using temp file name
+                    displayName = mInputFile.getName();
                 }
+                toolbarTop.setTitle(displayName);
+
             } else if (getIntent().getData().getScheme().equals(ContentResolver.SCHEME_FILE)) {
                 mInputFile = new File(getIntent().getData().getPath());
                 Log.d(LOGTAG, "SCHEME_FILE: getPath(): " + getIntent().getData().getPath());
@@ -280,12 +285,12 @@ public class LibreOfficeMainActivity extends AppCompatActivity implements Settin
         }
     }
 
-    // Loads a new Document
-    private void loadNewDocument(String newFilePath, String newDocumentType) {
-        mInputFile = new File(newFilePath);
-        LOKitShell.sendNewDocumentLoadEvent(newFilePath, newDocumentType);
+    // Loads a new Document and saves it to a temporary file
+    private void loadNewDocument(String newDocumentType) {
+        String tempFileName = "LibreOffice_" + UUID.randomUUID().toString();
+        mTempFile = new File(this.getCacheDir(), tempFileName);
+        LOKitShell.sendNewDocumentLoadEvent(mTempFile.getPath(), newDocumentType);
         isNewDocument = true;
-        toolbarTop.setTitle(mInputFile.getName());
     }
 
     public RectF getCurrentCursorPosition() {
@@ -376,19 +381,8 @@ public class LibreOfficeMainActivity extends AppCompatActivity implements Settin
         if (documentUri != null) {
             // case where file was opened using IDocumentProvider from within LO app
             saveFilesToCloud();
-        } else if (isNewDocument) {
-            // nothing to do for actual save, the actual (local) file is already handled
-            // by LOKitTileProvider
-            runOnUiThread(new Runnable() {
-                @Override
-                public void run() {
-                    Toast.makeText(LibreOfficeMainActivity.this, R.string.message_saved,
-                        Toast.LENGTH_SHORT).show();
-                }
-            });
-            setDocumentChanged(false);
         } else {
-            // case where file was passed via Intent
+            // case where file URI was passed via Intent
             if (isReadOnlyMode() || mInputFile == null || getIntent().getData() == null || !getIntent().getData().getScheme().equals(ContentResolver.SCHEME_CONTENT))
                 return;
 
@@ -1035,13 +1029,6 @@ public class LibreOfficeMainActivity extends AppCompatActivity implements Settin
         }
     }
 
-    // This method is used in LOKitTileProvider.java to show status of new file creation.
-    public void showSaveStatusMessage(boolean error) {
-        if (!error)
-            Snackbar.make(mDrawerLayout, getString(R.string.create_new_file_success) + mInputFile.getName(), Snackbar.LENGTH_LONG).show();
-        else
-            Snackbar.make(mDrawerLayout, getString(R.string.create_new_file_error) + mInputFile.getName(), Snackbar.LENGTH_LONG).show();    }
-
     public void showCustomStatusMessage(String message){
         Snackbar.make(mDrawerLayout, message, Snackbar.LENGTH_LONG).show();
     }