Fix some problems with moving in and out of detached state.

Loaders were not being re-initialized correctly when coming back
(this would also impact the back stack).  The ListView also wasn't
working correctly, and there were also problems with simply
re-using a Fragment instance after it had been removed.

Change-Id: I534b091ae09c0ef7ffffe9d68049e6840e8926b3

6 files changed, 118 insertions, 17 deletions

diff --git a/api/current.xml b/api/current.xml
index 6581042..a9f3e85 100644
--- a/api/current.xml
+++ b/api/current.xml
@@ -30614,6 +30614,17 @@
  visibility="public"
 >
 </method>
+<method name="isDetached"
+ return="boolean"
+ abstract="false"
+ native="false"
+ synchronized="false"
+ static="false"
+ final="true"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</method>
 <method name="isHidden"
  return="boolean"
  abstract="false"
diff --git a/core/java/android/app/Activity.java b/core/java/android/app/Activity.java
index b739e10..e0a2ce8 100644
--- a/core/java/android/app/Activity.java
+++ b/core/java/android/app/Activity.java
@@ -4413,7 +4413,9 @@ public class Activity extends ContextThemeWrapper
         mFragments.dispatchStart();
         if (mAllLoaderManagers != null) {
             for (int i=mAllLoaderManagers.size()-1; i>=0; i--) {
-                mAllLoaderManagers.valueAt(i).finishRetain();
+                LoaderManagerImpl lm = mAllLoaderManagers.valueAt(i);
+                lm.finishRetain();
+                lm.doReportStart();
             }
         }
     }
diff --git a/core/java/android/app/Fragment.java b/core/java/android/app/Fragment.java
index 14ffd3b..f2be9ad 100644
--- a/core/java/android/app/Fragment.java
+++ b/core/java/android/app/Fragment.java
@@ -587,11 +587,6 @@ public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener
         mWho = "android:fragment:" + mIndex;
    }
     
-    final void clearIndex() {
-        mIndex = -1;
-        mWho = null;
-    }
-    
     final boolean isInBackStack() {
         return mBackStackNesting > 0;
     }
@@ -783,6 +778,15 @@ public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener
     }
 
     /**
+     * Return true if the fragment has been explicitly detached from the UI.
+     * That is, {@link FragmentTransaction#detach(Fragment)
+     * FragmentTransaction.detach(Fragment)} has been used on it.
+     */
+    final public boolean isDetached() {
+        return mDetached;
+    }
+
+    /**
      * Return true if this fragment is currently being removed from its
      * activity.  This is  <em>not</em> whether its activity is finishing, but
      * rather whether it is in the process of being removed from its activity.
@@ -1203,6 +1207,35 @@ public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener
     }
 
     /**
+     * Called by the fragment manager once this fragment has been removed,
+     * so that we don't have any left-over state if the application decides
+     * to re-use the instance.  This only clears state that the framework
+     * internally manages, not things the application sets.
+     */
+    void initState() {
+        mIndex = -1;
+        mWho = null;
+        mAdded = false;
+        mRemoving = false;
+        mResumed = false;
+        mFromLayout = false;
+        mInLayout = false;
+        mRestored = false;
+        mBackStackNesting = 0;
+        mFragmentManager = null;
+        mActivity = mImmediateActivity = null;
+        mFragmentId = 0;
+        mContainerId = 0;
+        mTag = null;
+        mHidden = false;
+        mDetached = false;
+        mRetaining = false;
+        mLoaderManager = null;
+        mLoadersStarted = false;
+        mCheckedForLoaderManager = false;
+    }
+
+    /**
      * Called when the fragment is no longer attached to its activity.  This
      * is called after {@link #onDestroy()}.
      */
@@ -1429,6 +1462,13 @@ public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener
         }
     }
 
+    void performStart() {
+        onStart();
+        if (mLoaderManager != null) {
+            mLoaderManager.doReportStart();
+        }
+    }
+
     void performStop() {
         onStop();
         
@@ -1447,4 +1487,11 @@ public class Fragment implements ComponentCallbacks, OnCreateContextMenuListener
             }
         }
     }
+
+    void performDestroyView() {
+        onDestroyView();
+        if (mLoaderManager != null) {
+            mLoaderManager.doReportNextStart();
+        }
+    }
 }
diff --git a/core/java/android/app/FragmentManager.java b/core/java/android/app/FragmentManager.java
index 3b2e108..f05e2b3 100644
--- a/core/java/android/app/FragmentManager.java
+++ b/core/java/android/app/FragmentManager.java
@@ -803,7 +803,7 @@ final class FragmentManagerImpl extends FragmentManager {
                     if (newState > Fragment.STOPPED) {
                         if (DEBUG) Log.v(TAG, "moveto STARTED: " + f);
                         f.mCalled = false;
-                        f.onStart();
+                        f.performStart();
                         if (!f.mCalled) {
                             throw new SuperNotCalledException("Fragment " + f
                                     + " did not call through to super.onStart()");
@@ -856,7 +856,7 @@ final class FragmentManagerImpl extends FragmentManager {
                             }
                         }
                         f.mCalled = false;
-                        f.onDestroyView();
+                        f.performDestroyView();
                         if (!f.mCalled) {
                             throw new SuperNotCalledException("Fragment " + f
                                     + " did not call through to super.onDestroyView()");
@@ -1006,7 +1006,7 @@ final class FragmentManagerImpl extends FragmentManager {
         }
         mAvailIndices.add(f.mIndex);
         mActivity.invalidateFragmentIndex(f.mIndex);
-        f.clearIndex();
+        f.initState();
     }
     
     public void addFragment(Fragment fragment, boolean moveToStateNow) {
diff --git a/core/java/android/app/ListFragment.java b/core/java/android/app/ListFragment.java
index a5ee26c..dc8420e 100644
--- a/core/java/android/app/ListFragment.java
+++ b/core/java/android/app/ListFragment.java
@@ -167,7 +167,7 @@ public class ListFragment extends Fragment {
     TextView mStandardEmptyView;
     View mProgressContainer;
     View mListContainer;
-    boolean mSetEmptyText;
+    CharSequence mEmptyText;
     boolean mListShown;
 
     public ListFragment() {
@@ -210,6 +210,9 @@ public class ListFragment extends Fragment {
     public void onDestroyView() {
         mHandler.removeCallbacks(mRequestFocus);
         mList = null;
+        mListShown = false;
+        mEmptyView = mProgressContainer = mListContainer = null;
+        mStandardEmptyView = null;
         super.onDestroyView();
     }
 
@@ -289,10 +292,10 @@ public class ListFragment extends Fragment {
             throw new IllegalStateException("Can't be used with a custom content view");
         }
         mStandardEmptyView.setText(text);
-        if (!mSetEmptyText) {
+        if (mEmptyText == null) {
             mList.setEmptyView(mStandardEmptyView);
-            mSetEmptyText = true;
         }
+        mEmptyText = text;
     }
     
     /**
@@ -346,6 +349,9 @@ public class ListFragment extends Fragment {
                         getActivity(), android.R.anim.fade_out));
                 mListContainer.startAnimation(AnimationUtils.loadAnimation(
                         getActivity(), android.R.anim.fade_in));
+            } else {
+                mProgressContainer.clearAnimation();
+                mListContainer.clearAnimation();
             }
             mProgressContainer.setVisibility(View.GONE);
             mListContainer.setVisibility(View.VISIBLE);
@@ -355,6 +361,9 @@ public class ListFragment extends Fragment {
                         getActivity(), android.R.anim.fade_in));
                 mListContainer.startAnimation(AnimationUtils.loadAnimation(
                         getActivity(), android.R.anim.fade_out));
+            } else {
+                mProgressContainer.clearAnimation();
+                mListContainer.clearAnimation();
             }
             mProgressContainer.setVisibility(View.VISIBLE);
             mListContainer.setVisibility(View.GONE);
@@ -383,6 +392,8 @@ public class ListFragment extends Fragment {
                     com.android.internal.R.id.internalEmpty);
             if (mStandardEmptyView == null) {
                 mEmptyView = root.findViewById(android.R.id.empty);
+            } else {
+                mStandardEmptyView.setVisibility(View.GONE);
             }
             mProgressContainer = root.findViewById(com.android.internal.R.id.progressContainer);
             mListContainer = root.findViewById(com.android.internal.R.id.listContainer);
@@ -400,12 +411,17 @@ public class ListFragment extends Fragment {
             }
             if (mEmptyView != null) {
                 mList.setEmptyView(mEmptyView);
+            } else if (mEmptyText != null) {
+                mStandardEmptyView.setText(mEmptyText);
+                mList.setEmptyView(mStandardEmptyView);
             }
         }
         mListShown = true;
         mList.setOnItemClickListener(mOnClickListener);
         if (mAdapter != null) {
-            setListAdapter(mAdapter);
+            ListAdapter adapter = mAdapter;
+            mAdapter = null;
+            setListAdapter(adapter);
         } else {
             // We are starting without an adapter, so assume we won't
             // have our data right away and start with the progress indicator.
diff --git a/core/java/android/app/LoaderManager.java b/core/java/android/app/LoaderManager.java
index 164141c..46a008d 100644
--- a/core/java/android/app/LoaderManager.java
+++ b/core/java/android/app/LoaderManager.java
@@ -223,6 +223,7 @@ class LoaderManagerImpl extends LoaderManager {
         boolean mStarted;
         boolean mRetaining;
         boolean mRetainingStarted;
+        boolean mReportNextStart;
         boolean mDestroyed;
         boolean mListenerRegistered;
 
@@ -291,7 +292,7 @@ class LoaderManagerImpl extends LoaderManager {
                 }
             }
 
-            if (mStarted && mHaveData) {
+            if (mStarted && mHaveData && !mReportNextStart) {
                 // This loader has retained its data, either completely across
                 // a configuration change or just whatever the last data set
                 // was after being restarted from a stop, and now at the point of
@@ -302,6 +303,17 @@ class LoaderManagerImpl extends LoaderManager {
             }
         }
         
+        void reportStart() {
+            if (mStarted) {
+                if (mReportNextStart) {
+                    mReportNextStart = false;
+                    if (mHaveData) {
+                        callOnLoadFinished(mLoader, mData);
+                    }
+                }
+            }
+        }
+
         void stop() {
             if (DEBUG) Log.v(TAG, "  Stopping: " + this);
             mStarted = false;
@@ -449,10 +461,11 @@ class LoaderManagerImpl extends LoaderManager {
                 writer.print(prefix); writer.print("mData="); writer.println(mData);
             }
             writer.print(prefix); writer.print("mStarted="); writer.print(mStarted);
-                    writer.print(" mRetaining="); writer.print(mRetaining);
+                    writer.print(" mReportNextStart="); writer.print(mReportNextStart);
                     writer.print(" mDestroyed="); writer.println(mDestroyed);
-            writer.print(prefix); writer.print("mListenerRegistered=");
-                    writer.println(mListenerRegistered);
+            writer.print(prefix); writer.print("mRetaining="); writer.print(mRetaining);
+                    writer.print(" mRetainingStarted="); writer.print(mRetainingStarted);
+                    writer.print(" mListenerRegistered="); writer.println(mListenerRegistered);
             if (mPendingLoader != null) {
                 writer.print(prefix); writer.println("Pending Loader ");
                         writer.print(mPendingLoader); writer.println(":");
@@ -740,6 +753,18 @@ class LoaderManagerImpl extends LoaderManager {
         }
     }
     
+    void doReportNextStart() {
+        for (int i = mLoaders.size()-1; i >= 0; i--) {
+            mLoaders.valueAt(i).mReportNextStart = true;
+        }
+    }
+
+    void doReportStart() {
+        for (int i = mLoaders.size()-1; i >= 0; i--) {
+            mLoaders.valueAt(i).reportStart();
+        }
+    }
+
     void doDestroy() {
         if (!mRetaining) {
             if (DEBUG) Log.v(TAG, "Destroying Active in " + this);