2 files changed, 29 insertions, 3 deletions

diff --git a/src/com/android/bitmap/drawable/BasicBitmapDrawable.java b/src/com/android/bitmap/drawable/BasicBitmapDrawable.java
index 831f410..42c4fbf 100644
--- a/src/com/android/bitmap/drawable/BasicBitmapDrawable.java
+++ b/src/com/android/bitmap/drawable/BasicBitmapDrawable.java
@@ -135,6 +135,8 @@ public class BasicBitmapDrawable extends Drawable implements DecodeCallback,
      * Binds to the given key and start the decode process. This will first look in the cache, then
      * decode from the request key if not found.
      *
+     * The key being replaced will be kept in {@link #mPrevKey}.
+     *
      * All UI operations should be called from the UI thread.
      */
     public void bind(RequestKey key) {
@@ -150,11 +152,28 @@ public class BasicBitmapDrawable extends Drawable implements DecodeCallback,
      * Unbinds the current key and bitmap from the drawable. This will cause the bitmap to decrement
      * its ref count.
      *
+     * This will assume that you do not want to keep the unbound key in {@link #mPrevKey}.
+     *
      * All UI operations should be called from the UI thread.
      */
     public void unbind() {
+        unbind(false);
+    }
+
+    /**
+     * Unbinds the current key and bitmap from the drawable. This will cause the bitmap to decrement
+     * its ref count.
+     *
+     * If the temporary parameter is true, we will keep the unbound key in {@link #mPrevKey}.
+     *
+     * All UI operations should be called from the UI thread.
+     */
+    public void unbind(boolean temporary) {
         Trace.beginSection("unbind");
         setImage(null);
+        if (!temporary) {
+            mPrevKey = null;
+        }
         Trace.endSection();
     }
 
diff --git a/src/com/android/bitmap/view/BitmapDrawableImageView.java b/src/com/android/bitmap/view/BitmapDrawableImageView.java
index 5d42b6c..e9df6d3 100644
--- a/src/com/android/bitmap/view/BitmapDrawableImageView.java
+++ b/src/com/android/bitmap/view/BitmapDrawableImageView.java
@@ -34,6 +34,9 @@ import com.android.bitmap.drawable.BasicBitmapDrawable;
 public class BitmapDrawableImageView extends ImageView {
     private static final boolean HAS_TRANSIENT_STATE_SUPPORTED =
         Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN;
+    private static final boolean TEMPORARY = true;
+    private static final boolean PERMANENT = !TEMPORARY;
+
     private BasicBitmapDrawable mDrawable;
     private boolean mAttachedToWindow;
 
@@ -74,8 +77,12 @@ public class BitmapDrawableImageView extends ImageView {
     }
 
     private void unbindDrawable() {
+        unbindDrawable(PERMANENT);
+    }
+
+    private void unbindDrawable(boolean temporary) {
         if (mDrawable != null) {
-            mDrawable.unbind();
+            mDrawable.unbind(temporary);
         }
     }
 
@@ -121,7 +128,7 @@ public class BitmapDrawableImageView extends ImageView {
         super.onDetachedFromWindow();
         mAttachedToWindow = false;
         if (HAS_TRANSIENT_STATE_SUPPORTED && !hasTransientState()) {
-            unbindDrawable();
+            unbindDrawable(TEMPORARY);
         }
     }
 
@@ -129,7 +136,7 @@ public class BitmapDrawableImageView extends ImageView {
     public void setHasTransientState(boolean hasTransientState) {
         super.setHasTransientState(hasTransientState);
         if (!hasTransientState && !mAttachedToWindow) {
-            unbindDrawable();
+            unbindDrawable(TEMPORARY);
         }
     }
 }