Better data change handling for PhotoDataAdapter and PhotoView.

Change-Id: I0f67d918b95000d10786d2035286e036346bfa4e

3 files changed, 76 insertions, 59 deletions

diff --git a/src/com/android/gallery3d/app/PhotoDataAdapter.java b/src/com/android/gallery3d/app/PhotoDataAdapter.java
index df17a6cdb..d88b72ca8 100644
--- a/src/com/android/gallery3d/app/PhotoDataAdapter.java
+++ b/src/com/android/gallery3d/app/PhotoDataAdapter.java
@@ -128,10 +128,13 @@ public class PhotoDataAdapter implements PhotoPage.Model {
     // mCurrentIndex triggers the data loading and image loading.
     private int mCurrentIndex;
 
-    // mChanges keeps the version number (of MediaItem) about the previous,
-    // current, and next image. If the version number changes, we notify the
-    // view. This is used after a database reload or mCurrentIndex changes.
+    // mChanges keeps the version number (of MediaItem) about the images. If any
+    // of the version number changes, we notify the view. This is used after a
+    // database reload or mCurrentIndex changes.
     private final long mChanges[] = new long[IMAGE_CACHE_SIZE];
+    // mPaths keeps the corresponding Path (of MediaItem) for the images. This
+    // is used to determine the item movement.
+    private final Path mPaths[] = new Path[IMAGE_CACHE_SIZE];
 
     private final Handler mMainHandler;
     private final ThreadPool mThreadPool;
@@ -158,7 +161,8 @@ public class PhotoDataAdapter implements PhotoPage.Model {
     // The path of the current viewing item will be stored in mItemPath.
     // If mItemPath is not null, mCurrentIndex is only a hint for where we
     // can find the item. If mItemPath is null, then we use the mCurrentIndex to
-    // find the image being viewed.
+    // find the image being viewed. cameraIndex is the index of the camera
+    // preview. If cameraIndex < 0, there is no camera preview.
     public PhotoDataAdapter(GalleryActivity activity, PhotoView view,
             MediaSet mediaSet, Path itemPath, int indexHint, int cameraIndex) {
         mSource = Utils.checkNotNull(mediaSet);
@@ -199,20 +203,73 @@ public class PhotoDataAdapter implements PhotoPage.Model {
         updateSlidingWindow();
     }
 
-    private long getVersion(int index) {
-        if (index < 0 || index >= mSize) return MediaObject.INVALID_DATA_VERSION;
+    private MediaItem getItemInternal(int index) {
+        if (index < 0 || index >= mSize) return null;
         if (index >= mContentStart && index < mContentEnd) {
-            MediaItem item = mData[index % DATA_CACHE_SIZE];
-            if (item != null) return item.getDataVersion();
+            return mData[index % DATA_CACHE_SIZE];
         }
-        return MediaObject.INVALID_DATA_VERSION;
+        return null;
+    }
+
+    private long getVersion(int index) {
+        MediaItem item = getItemInternal(index);
+        if (item == null) return MediaObject.INVALID_DATA_VERSION;
+        return item.getDataVersion();
+    }
+
+    private Path getPath(int index) {
+        MediaItem item = getItemInternal(index);
+        if (item == null) return null;
+        return item.getPath();
     }
 
     private void fireDataChange() {
+        // First check if data actually changed.
+        boolean changed = false;
         for (int i = -SCREEN_NAIL_MAX; i <= SCREEN_NAIL_MAX; ++i) {
-            mChanges[i + SCREEN_NAIL_MAX] = getVersion(mCurrentIndex + i);
+            long newVersion = getVersion(mCurrentIndex + i);
+            if (mChanges[i + SCREEN_NAIL_MAX] != newVersion) {
+                mChanges[i + SCREEN_NAIL_MAX] = newVersion;
+                changed = true;
+            }
         }
-        mPhotoView.notifyDataChange(mChanges, -mCurrentIndex,
+
+        if (!changed) return;
+
+        // Now calculate the fromIndex array. fromIndex represents the item
+        // movement. It records the index where the picture come from. The
+        // special value Integer.MAX_VALUE means it's a new picture.
+        final int N = IMAGE_CACHE_SIZE;
+        int fromIndex[] = new int[N];
+
+        // Remember the old path array.
+        Path oldPaths[] = new Path[N];
+        System.arraycopy(mPaths, 0, oldPaths, 0, N);
+
+        // Update the mPaths array.
+        for (int i = 0; i < N; ++i) {
+            mPaths[i] = getPath(mCurrentIndex + i - SCREEN_NAIL_MAX);
+        }
+
+        // Calculate the fromIndex array.
+        for (int i = 0; i < N; i++) {
+            Path p = mPaths[i];
+            if (p == null) {
+                fromIndex[i] = Integer.MAX_VALUE;
+                continue;
+            }
+
+            // Try to find the same path in the old array
+            int j;
+            for (j = 0; j < N; j++) {
+                if (oldPaths[j] == p) {
+                    break;
+                }
+            }
+            fromIndex[i] = (j < N) ? j - SCREEN_NAIL_MAX : Integer.MAX_VALUE;
+        }
+
+        mPhotoView.notifyDataChange(fromIndex, -mCurrentIndex,
                 mSize - 1 - mCurrentIndex);
     }
 
@@ -542,7 +599,7 @@ public class PhotoDataAdapter implements PhotoPage.Model {
                 bitmap = BitmapUtils.rotateBitmap(bitmap,
                     mItem.getRotation() - mItem.getFullImageRotation(), true);
             }
-            return new BitmapScreenNail(bitmap);
+            return bitmap == null ? null : new BitmapScreenNail(bitmap);
         }
     }
 
diff --git a/src/com/android/gallery3d/data/LocalImage.java b/src/com/android/gallery3d/data/LocalImage.java
index 4f2797e02..f96aca3e3 100644
--- a/src/com/android/gallery3d/data/LocalImage.java
+++ b/src/com/android/gallery3d/data/LocalImage.java
@@ -57,7 +57,7 @@ public class LocalImage extends LocalMediaItem {
     private static final int INDEX_DATA = 8;
     private static final int INDEX_ORIENTATION = 9;
     private static final int INDEX_BUCKET_ID = 10;
-    private static final int INDEX_SIZE_ID = 11;
+    private static final int INDEX_SIZE = 11;
     private static final int INDEX_WIDTH = 12;
     private static final int INDEX_HEIGHT = 13;
 
@@ -74,9 +74,8 @@ public class LocalImage extends LocalMediaItem {
             ImageColumns.ORIENTATION,   // 9
             ImageColumns.BUCKET_ID,     // 10
             ImageColumns.SIZE,          // 11
-            // These should be changed to proper names after they are made public.
-            "width", // ImageColumns.WIDTH,         // 12
-            "height", // ImageColumns.HEIGHT         // 13
+            ImageColumns.WIDTH,         // 12
+            ImageColumns.HEIGHT         // 13
     };
 
     private final GalleryApp mApplication;
@@ -121,7 +120,7 @@ public class LocalImage extends LocalMediaItem {
         filePath = cursor.getString(INDEX_DATA);
         rotation = cursor.getInt(INDEX_ORIENTATION);
         bucketId = cursor.getInt(INDEX_BUCKET_ID);
-        fileSize = cursor.getLong(INDEX_SIZE_ID);
+        fileSize = cursor.getLong(INDEX_SIZE);
         width = cursor.getInt(INDEX_WIDTH);
         height = cursor.getInt(INDEX_HEIGHT);
     }
@@ -143,7 +142,7 @@ public class LocalImage extends LocalMediaItem {
         filePath = uh.update(filePath, cursor.getString(INDEX_DATA));
         rotation = uh.update(rotation, cursor.getInt(INDEX_ORIENTATION));
         bucketId = uh.update(bucketId, cursor.getInt(INDEX_BUCKET_ID));
-        fileSize = uh.update(fileSize, cursor.getLong(INDEX_SIZE_ID));
+        fileSize = uh.update(fileSize, cursor.getLong(INDEX_SIZE));
         width = uh.update(width, cursor.getInt(INDEX_WIDTH));
         height = uh.update(height, cursor.getInt(INDEX_HEIGHT));
         return uh.isUpdated();
diff --git a/src/com/android/gallery3d/ui/PhotoView.java b/src/com/android/gallery3d/ui/PhotoView.java
index cd11b8e27..dce37289e 100644
--- a/src/com/android/gallery3d/ui/PhotoView.java
+++ b/src/com/android/gallery3d/ui/PhotoView.java
@@ -142,9 +142,6 @@ public class PhotoView extends GLView {
     private final RangeArray<Picture> mPictures =
             new RangeArray<Picture>(-SCREEN_NAIL_MAX, SCREEN_NAIL_MAX);
 
-    private final long mDataVersion[] = new long[2 * SCREEN_NAIL_MAX + 1];
-    private final int mFromIndex[] = new int[2 * SCREEN_NAIL_MAX + 1];
-
     private final MyGestureListener mGestureListener;
     private final GestureRecognizer mGestureRecognizer;
     private final PositionController mPositionController;
@@ -224,7 +221,6 @@ public class PhotoView extends GLView {
                     }
                 });
         mVideoPlayIcon = new ResourceTexture(context, R.drawable.ic_control_play);
-        Arrays.fill(mDataVersion, INVALID_DATA_VERSION);
         for (int i = -SCREEN_NAIL_MAX; i <= SCREEN_NAIL_MAX; i++) {
             if (i == 0) {
                 mPictures.put(i, new FullPicture());
@@ -305,47 +301,12 @@ public class PhotoView extends GLView {
     //  Data/Image change notifications
     ////////////////////////////////////////////////////////////////////////////
 
-    public void notifyDataChange(long[] versions, int prevBound, int nextBound) {
+    public void notifyDataChange(int[] fromIndex, int prevBound, int nextBound) {
         mPrevBound = prevBound;
         mNextBound = nextBound;
 
-        // Check if the data version actually changed.
-        boolean changed = false;
-        int N = 2 * SCREEN_NAIL_MAX + 1;
-        for (int i = 0; i < N; i++) {
-            if (versions[i] != mDataVersion[i]) {
-                changed = true;
-                break;
-            }
-        }
-        if (!changed) return;
-
-        // Create the mFromIndex array, which records the index where the picture
-        // come from. The value Integer.MAX_VALUE means it's a new picture.
-        for (int i = 0; i < N; i++) {
-            long v = versions[i];
-            if (v == INVALID_DATA_VERSION) {
-                mFromIndex[i] = Integer.MAX_VALUE;
-                continue;
-            }
-
-            // Try to find the same version number in the old array
-            int j;
-            for (j = 0; j < N; j++) {
-                if (mDataVersion[j] == v) {
-                    break;
-                }
-            }
-            mFromIndex[i] = (j < N) ? j - SCREEN_NAIL_MAX : Integer.MAX_VALUE;
-        }
-
-        // Copy the new data version
-        for (int i = 0; i < N; i++) {
-            mDataVersion[i] = versions[i];
-        }
-
         // Move the boxes
-        mPositionController.moveBox(mFromIndex, mPrevBound < 0, mNextBound > 0,
+        mPositionController.moveBox(fromIndex, mPrevBound < 0, mNextBound > 0,
                 mModel.isCamera(0));
 
         // Update the ScreenNails.