1 files changed, 114 insertions, 0 deletions
diff --git a/src/com/android/gallery3d/ui/AbstractDisplayItem.java b/src/com/android/gallery3d/ui/AbstractDisplayItem.java
new file mode 100644
index 000000000..aad3919b5
--- /dev/null
+++ b/src/com/android/gallery3d/ui/AbstractDisplayItem.java
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.gallery3d.ui;
+
+import com.android.gallery3d.data.MediaItem;
+
+import android.graphics.Bitmap;
+
+public abstract class AbstractDisplayItem extends DisplayItem {
+
+    private static final String TAG = "AbstractDisplayItem";
+
+    private static final int STATE_INVALID = 0x01;
+    private static final int STATE_VALID = 0x02;
+    private static final int STATE_UPDATING = 0x04;
+    private static final int STATE_CANCELING = 0x08;
+    private static final int STATE_ERROR = 0x10;
+
+    private int mState = STATE_INVALID;
+    private boolean mImageRequested = false;
+    private boolean mRecycling = false;
+    private Bitmap mBitmap;
+
+    protected final MediaItem mMediaItem;
+    private int mRotation;
+
+    public AbstractDisplayItem(MediaItem item) {
+        mMediaItem = item;
+        if (item == null) mState = STATE_ERROR;
+        if (item != null) mRotation = mMediaItem.getRotation();
+    }
+
+    protected void updateImage(Bitmap bitmap, boolean isCancelled) {
+        if (mRecycling) {
+            return;
+        }
+
+        if (isCancelled && bitmap == null) {
+            mState = STATE_INVALID;
+            if (mImageRequested) {
+                // request image again.
+                requestImage();
+            }
+            return;
+        }
+
+        mBitmap = bitmap;
+        mState = bitmap == null ? STATE_ERROR : STATE_VALID ;
+        onBitmapAvailable(mBitmap);
+    }
+
+    @Override
+    public int getRotation() {
+        return mRotation;
+    }
+
+    @Override
+    public long getIdentity() {
+        return mMediaItem != null
+                ? System.identityHashCode(mMediaItem.getPath())
+                : System.identityHashCode(this);
+    }
+
+    public void requestImage() {
+        mImageRequested = true;
+        if (mState == STATE_INVALID) {
+            mState = STATE_UPDATING;
+            startLoadBitmap();
+        }
+    }
+
+    public void cancelImageRequest() {
+        mImageRequested = false;
+        if (mState == STATE_UPDATING) {
+            mState = STATE_CANCELING;
+            cancelLoadBitmap();
+        }
+    }
+
+    private boolean inState(int states) {
+        return (mState & states) != 0;
+    }
+
+    public void recycle() {
+        if (!inState(STATE_UPDATING | STATE_CANCELING)) {
+            if (mBitmap != null) mBitmap = null;
+        } else {
+            mRecycling = true;
+            cancelImageRequest();
+        }
+    }
+
+    public boolean isRequestInProgress() {
+        return mImageRequested && inState(STATE_UPDATING | STATE_CANCELING);
+    }
+
+    abstract protected void startLoadBitmap();
+    abstract protected void cancelLoadBitmap();
+    abstract protected void onBitmapAvailable(Bitmap bitmap);
+}