Merge "Get rid of "flashies" in the action bar."

2 files changed, 134 insertions, 5 deletions

diff --git a/src/com/android/gallery3d/util/GalleryUtils.java b/src/com/android/gallery3d/util/GalleryUtils.java
index 680361183..df29a5eb4 100644
--- a/src/com/android/gallery3d/util/GalleryUtils.java
+++ b/src/com/android/gallery3d/util/GalleryUtils.java
@@ -271,11 +271,7 @@ public class GalleryUtils {
 
     public static void setSpinnerVisibility(final Activity activity,
             final boolean visible) {
-        activity.runOnUiThread(new Runnable() {
-            public void run() {
-                activity.setProgressBarIndeterminateVisibility(visible);
-            }
-        });
+        SpinnerVisibilitySetter.getInstance(activity).setSpinnerVisibility(visible);
     }
 
     public static int determineTypeBits(Context context, Intent intent) {
diff --git a/src/com/android/gallery3d/util/SpinnerVisibilitySetter.java b/src/com/android/gallery3d/util/SpinnerVisibilitySetter.java
new file mode 100644
index 000000000..75b1fa4ab
--- /dev/null
+++ b/src/com/android/gallery3d/util/SpinnerVisibilitySetter.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2011 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.util;
+
+import android.app.Activity;
+import android.os.Handler;
+import android.os.Message;
+import android.os.SystemClock;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * This class manages the visibility of the progress spinner in the action bar for an
+ * Activity. It filters out short-lived appearances of the progress spinner by only
+ * showing the spinner if it hasn't been hidden again before the end of a specified
+ * delay period. It also enforces a minimum display time once the spinner is made visible.
+ * This meant to cut down on the frequent "flashes" of the progress spinner.
+ */
+public class SpinnerVisibilitySetter {
+
+    private static final int SHOW_SPINNER_REQUESTED = 0;
+    private static final int HIDE_SPINNER_REQUESTED = 1;
+    private static final int SHOW_SPINNER_DELAY_REACHED = 2;
+    private static final int HIDE_SPINNER_DELAY_REACHED = 3;
+
+    // Amount of time after a show request that the progress spinner is actually made visible.
+    // This means that any show/hide requests that happen subsequently within this period
+    // of time will be ignored.
+    private static final long SPINNER_DISPLAY_DELAY = 1000;
+
+    // The minimum amount of time the progress spinner must be visible before it can be hidden.
+    private static final long MIN_SPINNER_DISPLAY_TIME = 2000;
+
+    private boolean mPendingVisibilityRequest = false;
+    private boolean mActiveVisibilityRequest = false;
+    private long mSpinnerVisibilityStartTime;
+
+    Handler mHandler = new Handler() {
+
+        @Override
+        public void handleMessage(Message msg) {
+            switch(msg.what) {
+                case SHOW_SPINNER_REQUESTED:
+                    mPendingVisibilityRequest = true;
+                    sendEmptyMessageDelayed(SHOW_SPINNER_DELAY_REACHED, SPINNER_DISPLAY_DELAY);
+                    break;
+                case HIDE_SPINNER_REQUESTED:
+                    mPendingVisibilityRequest = false;
+                    if (!mActiveVisibilityRequest) {
+                        // We haven't requested to show the spinner so no need to decide
+                        // when to hide it.
+                        break;
+                    }
+
+                    long currTime = SystemClock.uptimeMillis();
+                    if (currTime - mSpinnerVisibilityStartTime > MIN_SPINNER_DISPLAY_TIME) {
+                        // The spinner has already been visible longer than the requisite min
+                        // display time. Send the hide message immediately.
+                        sendEmptyMessage(HIDE_SPINNER_DELAY_REACHED);
+                    } else {
+                        // The spinner is visible but hasn't been visible for long enough yet.
+                        // Send a delayed hide message.
+                        sendEmptyMessageAtTime(HIDE_SPINNER_DELAY_REACHED,
+                                mSpinnerVisibilityStartTime + MIN_SPINNER_DISPLAY_TIME);
+                    }
+                    break;
+                case SHOW_SPINNER_DELAY_REACHED:
+                    if (mPendingVisibilityRequest) {
+                        mPendingVisibilityRequest = false;
+                        mActiveVisibilityRequest = true;
+
+                        // Even though the spinner isn't visible quite yet, lets set this
+                        // here to avoid possible cross-thread synchronization issues.
+                        mSpinnerVisibilityStartTime = SystemClock.uptimeMillis();
+                        mActivity.runOnUiThread(new SetProgressVisibilityRunnable(true));
+                    }
+                    break;
+                case HIDE_SPINNER_DELAY_REACHED:
+                    mActiveVisibilityRequest = false;
+                    mActivity.runOnUiThread(new SetProgressVisibilityRunnable(false));
+                    break;
+            }
+        }
+    };
+    static final Map<Activity, SpinnerVisibilitySetter> sInstanceMap =
+            new HashMap<Activity, SpinnerVisibilitySetter>();
+    private Activity mActivity;
+
+    private SpinnerVisibilitySetter(Activity activity) {
+        mActivity = activity;
+    }
+
+    public static SpinnerVisibilitySetter getInstance(Activity activity) {
+        synchronized(sInstanceMap) {
+            if (sInstanceMap.get(activity) == null) {
+                sInstanceMap.put(activity, new SpinnerVisibilitySetter(activity));
+            }
+            return sInstanceMap.get(activity);
+        }
+    }
+
+    public void setSpinnerVisibility(boolean visible) {
+        mHandler.sendEmptyMessage(visible ? SHOW_SPINNER_REQUESTED : HIDE_SPINNER_REQUESTED);
+    }
+
+    private class SetProgressVisibilityRunnable implements Runnable {
+        boolean mVisible;
+
+        public SetProgressVisibilityRunnable(boolean visible) {
+            mVisible = visible;
+        }
+
+        @Override
+        public void run() {
+            mActivity.setProgressBarIndeterminateVisibility(mVisible);
+        }
+    }
+}