From a8171f50deb368d4c3862b85f79e503198cb1b11 Mon Sep 17 00:00:00 2001
From: David Allison <62114487+david-allison-1@users.noreply.github.com>
Date: Mon, 20 Apr 2020 11:19:37 +0100
Subject: [PATCH] Visual Editor: Handle Activity destruction

---
 .../activity/VisualEditorActivity.java        | 46 +++++++++++++++++--
 .../com/ichi2/utils/LargeObjectStorage.java   |  5 ++
 2 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/multimediacard/activity/VisualEditorActivity.java b/AnkiDroid/src/main/java/com/ichi2/anki/multimediacard/activity/VisualEditorActivity.java
index ba2ec0ad01d5..51e68741c910 100644
--- a/AnkiDroid/src/main/java/com/ichi2/anki/multimediacard/activity/VisualEditorActivity.java
+++ b/AnkiDroid/src/main/java/com/ichi2/anki/multimediacard/activity/VisualEditorActivity.java
@@ -34,6 +34,7 @@
 import com.ichi2.utils.AssetReader;
 import com.ichi2.utils.JSONObject;
 import com.ichi2.utils.LargeObjectStorage;
+import com.ichi2.utils.LargeObjectStorage.StorageData;
 import com.ichi2.utils.LargeObjectStorage.StorageKey;
 import com.ichi2.utils.WebViewDebugging;
 import com.jaredrummler.android.colorpicker.ColorPickerDialog;
@@ -42,6 +43,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.Serializable;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Locale;
@@ -103,7 +105,7 @@ protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.visual_editor);
 
-        if (!setFieldsOnStartup()) {
+        if (!setFieldsOnStartup(savedInstanceState)) {
             failStartingVisualEditor();
             return;
         }
@@ -376,17 +378,23 @@ private void handleSelectionChanged(SelectionType selectionType) {
     }
 
 
-    private boolean setFieldsOnStartup() {
+    private boolean setFieldsOnStartup(Bundle savedInstanceState) {
+
+        tryDeserializeSavedState(savedInstanceState);
         Bundle extras = this.getIntent().getExtras();
         if (extras == null) {
             Timber.w("No Extras in Bundle");
             return false;
         }
 
-        mCurrentText = mLargeObjectStorage.getSingleInstance(STORAGE_CURRENT_FIELD, extras);
+        if (mCurrentText == null) {
+            mCurrentText = mLargeObjectStorage.getSingleInstance(STORAGE_CURRENT_FIELD, extras);
+        }
         Integer index = (Integer) extras.getSerializable(VisualEditorActivity.EXTRA_FIELD_INDEX);
 
-        this.mFields = mLargeObjectStorage.getSingleInstance (STORAGE_EXTRA_FIELDS, extras);
+        if (mFields == null) {
+            this.mFields = mLargeObjectStorage.getSingleInstance (STORAGE_EXTRA_FIELDS, extras);
+        }
         Long modelId = (Long) extras.getSerializable(VisualEditorActivity.EXTRA_MODEL_ID);
 
         if (mCurrentText == null) {
@@ -419,6 +427,19 @@ private boolean setFieldsOnStartup() {
     }
 
 
+    private void tryDeserializeSavedState(@Nullable Bundle savedInstanceState) {
+        if (savedInstanceState == null) {
+            return;
+        }
+        if (mLargeObjectStorage.hasKey(STORAGE_CURRENT_FIELD, savedInstanceState)) {
+            mCurrentText = mLargeObjectStorage.getSingleInstance(STORAGE_CURRENT_FIELD, savedInstanceState);
+        }
+        if (mLargeObjectStorage.hasKey(STORAGE_EXTRA_FIELDS, savedInstanceState)) {
+            mFields = mLargeObjectStorage.getSingleInstance(STORAGE_EXTRA_FIELDS, savedInstanceState);
+        }
+    }
+
+
     private void failStartingVisualEditor() {
         UIUtils.showThemedToast(this, "Unable to start visual editor", false);
         finishCancel();
@@ -601,6 +622,23 @@ private void resetSelectionType() {
     }
 
 
+    @Override
+    protected void onSaveInstanceState(@NonNull Bundle outState) {
+        super.onSaveInstanceState(outState);
+        storeDataNoException(outState, STORAGE_CURRENT_FIELD.asData(mCurrentText));
+        storeDataNoException(outState, STORAGE_EXTRA_FIELDS.asData(mFields));
+    }
+
+
+    private <T extends Serializable> void storeDataNoException(@NonNull Bundle outState, StorageData<T> data) {
+        try {
+            mLargeObjectStorage.storeSingleInstance(data, outState);
+        } catch (Exception e) {
+            Timber.e(e, "failed to store '%s'", STORAGE_CURRENT_FIELD.getBundleKey());
+        }
+    }
+
+
     private void finishWithSuccess() {
         IField f = new TextField();
         f.setText(mCurrentText);
diff --git a/AnkiDroid/src/main/java/com/ichi2/utils/LargeObjectStorage.java b/AnkiDroid/src/main/java/com/ichi2/utils/LargeObjectStorage.java
index 382b522e3ed5..7bf3626b6dca 100644
--- a/AnkiDroid/src/main/java/com/ichi2/utils/LargeObjectStorage.java
+++ b/AnkiDroid/src/main/java/com/ichi2/utils/LargeObjectStorage.java
@@ -98,6 +98,11 @@ public <T extends Serializable> T getSingleInstance(StorageKey<T> key, Bundle bu
     }
 
 
+    public <T extends Serializable> boolean hasKey(StorageKey<T> storageCurrentField, Bundle bundle) {
+        return bundle != null && bundle.containsKey(storageCurrentField.getBundleKey());
+    }
+
+
     public static class StorageData<T extends Serializable> {
         private final StorageKey<T> mKey;
         private final T mData;