Merge "Change the "start deferred" fragment API to "user visible hint"" into ics-mr1

adamp · Android (Google) Code Review · commit b1dbf8e605c2 · 2011-11-07T14:56:36.000-08:00
diff --git a/api/current.txt b/api/current.txt
@@ -3235,6 +3235,7 @@ package android.app {
     method public final android.app.Fragment getTargetFragment();
     method public final int getTargetRequestCode();
     method public final java.lang.CharSequence getText(int);
+    method public boolean getUserVisibleHint();
     method public android.view.View getView();
     method public final int hashCode();
     method public static android.app.Fragment instantiate(android.content.Context, java.lang.String);
@@ -3245,7 +3246,6 @@ package android.app {
     method public final boolean isInLayout();
     method public final boolean isRemoving();
     method public final boolean isResumed();
-    method public boolean isStartDeferred();
     method public final boolean isVisible();
     method public void onActivityCreated(android.os.Bundle);
     method public void onActivityResult(int, int, android.content.Intent);
@@ -3281,8 +3281,8 @@ package android.app {
     method public void setInitialSavedState(android.app.Fragment.SavedState);
     method public void setMenuVisibility(boolean);
     method public void setRetainInstance(boolean);
-    method public void setStartDeferred(boolean);
     method public void setTargetFragment(android.app.Fragment, int);
+    method public void setUserVisibleHint(boolean);
     method public void startActivity(android.content.Intent);
     method public void startActivityForResult(android.content.Intent, int);
     method public void unregisterForContextMenu(android.view.View);
diff --git a/core/java/android/app/Fragment.java b/core/java/android/app/Fragment.java
@@ -458,6 +458,9 @@ public class Fragment implements ComponentCallbacks2, OnCreateContextMenuListene
     // have been started and their loaders are finished.
     boolean mDeferStart;
 
+    // Hint provided by the app that this fragment is currently visible to the user.
+    boolean mUserVisibleHint = true;
+
     LoaderManagerImpl mLoaderManager;
     boolean mLoadersStarted;
     boolean mCheckedForLoaderManager;
@@ -915,31 +918,32 @@ public void setMenuVisibility(boolean menuVisible) {
     }
 
     /**
-     * Set whether this fragment should enter the started state as normal or if
-     * start should be deferred until a system-determined convenient time, such
-     * as after any loaders have completed their work.
+     * Set a hint to the system about whether this fragment's UI is currently visible
+     * to the user. This hint defaults to true and is persistent across fragment instance
+     * state save and restore.
      *
-     * <p>This option is not sticky across fragment starts; after a deferred start
-     * completes this option will be set to false.</p>
+     * <p>An app may set this to false to indicate that the fragment's UI is
+     * scrolled out of visibility or is otherwise not directly visible to the user.
+     * This may be used by the system to prioritize operations such as fragment lifecycle updates
+     * or loader ordering behavior.</p>
      *
-     * @param deferResume true if this fragment can defer its resume until after others
+     * @param isVisibleToUser true if this fragment's UI is currently visible to the user (default),
+     *                        false if it is not.
      */
-    public void setStartDeferred(boolean deferResume) {
-        if (mDeferStart && !deferResume) {
+    public void setUserVisibleHint(boolean isVisibleToUser) {
+        if (!mUserVisibleHint && isVisibleToUser && mState < STARTED) {
             mFragmentManager.performPendingDeferredStart(this);
         }
-        mDeferStart = deferResume;
+        mUserVisibleHint = isVisibleToUser;
+        mDeferStart = !isVisibleToUser;
     }
 
     /**
-     * Returns true if this fragment's move to the started state has been deferred.
-     * If this returns true it will be started once other fragments' loaders
-     * have finished running.
-     *
-     * @return true if this fragment's start has been deferred.
+     * @return The current value of the user-visible hint on this fragment.
+     * @see #setUserVisibleHint(boolean)
      */
-    public boolean isStartDeferred() {
-        return mDeferStart;
+    public boolean getUserVisibleHint() {
+        return mUserVisibleHint;
     }
 
     /**
@@ -1477,7 +1481,8 @@ public void dump(String prefix, FileDescriptor fd, PrintWriter writer, String[]
                 writer.print(" mMenuVisible="); writer.print(mMenuVisible);
                 writer.print(" mHasMenu="); writer.println(mHasMenu);
         writer.print(prefix); writer.print("mRetainInstance="); writer.print(mRetainInstance);
-                writer.print(" mRetaining="); writer.println(mRetaining);
+                writer.print(" mRetaining="); writer.print(mRetaining);
+                writer.print(" mUserVisibleHint="); writer.println(mUserVisibleHint);
         if (mFragmentManager != null) {
             writer.print(prefix); writer.print("mFragmentManager=");
                     writer.println(mFragmentManager);
diff --git a/core/java/android/app/FragmentManager.java b/core/java/android/app/FragmentManager.java
@@ -382,6 +382,7 @@ final class FragmentManagerImpl extends FragmentManager {
     static final String TARGET_REQUEST_CODE_STATE_TAG = "android:target_req_state";
     static final String TARGET_STATE_TAG = "android:target_state";
     static final String VIEW_STATE_TAG = "android:view_state";
+    static final String USER_VISIBLE_HINT_TAG = "android:user_visible_hint";
 
     ArrayList<Runnable> mPendingActions;
     Runnable[] mTmpActions;
@@ -406,6 +407,7 @@ final class FragmentManagerImpl extends FragmentManager {
     boolean mStateSaved;
     boolean mDestroyed;
     String mNoTransactionsBecause;
+    boolean mHavePendingDeferredStart;
     
     // Temporary vars for state save and restore.
     Bundle mStateBundle = null;
@@ -711,6 +713,11 @@ Animator loadAnimator(Fragment fragment, int transit, boolean enter,
     
     public void performPendingDeferredStart(Fragment f) {
         if (f.mDeferStart) {
+            if (mExecutingActions) {
+                // Wait until we're done executing our pending transactions
+                mHavePendingDeferredStart = true;
+                return;
+            }
             f.mDeferStart = false;
             moveToState(f, mCurState, 0, 0);
         }
@@ -757,6 +764,14 @@ void moveToState(Fragment f, int newState, int transit, int transitionStyle) {
                             f.mTargetRequestCode = f.mSavedFragmentState.getInt(
                                     FragmentManagerImpl.TARGET_REQUEST_CODE_STATE_TAG, 0);
                         }
+                        f.mUserVisibleHint = f.mSavedFragmentState.getBoolean(
+                                FragmentManagerImpl.USER_VISIBLE_HINT_TAG, true);
+                        if (!f.mUserVisibleHint) {
+                            f.mDeferStart = true;
+                            if (newState > Fragment.STOPPED) {
+                                newState = Fragment.STOPPED;
+                            }
+                        }
                     }
                     f.mActivity = mActivity;
                     f.mFragmentManager = mActivity.mFragments;
@@ -1343,7 +1358,7 @@ public boolean execPendingActions() {
             
             synchronized (this) {
                 if (mPendingActions == null || mPendingActions.size() == 0) {
-                    return didSomething;
+                    break;
                 }
                 
                 numActions = mPendingActions.size();
@@ -1363,8 +1378,23 @@ public boolean execPendingActions() {
             mExecutingActions = false;
             didSomething = true;
         }
+
+        if (mHavePendingDeferredStart) {
+            boolean loadersRunning = false;
+            for (int i=0; i<mActive.size(); i++) {
+                Fragment f = mActive.get(i);
+                if (f != null && f.mLoaderManager != null) {
+                    loadersRunning |= f.mLoaderManager.hasRunningLoaders();
+                }
+            }
+            if (!loadersRunning) {
+                mHavePendingDeferredStart = false;
+                startPendingDeferredFragments();
+            }
+        }
+        return didSomething;
     }
-    
+
     void reportBackStackChanged() {
         if (mBackStackChangeListeners != null) {
             for (int i=0; i<mBackStackChangeListeners.size(); i++) {
@@ -1500,6 +1530,10 @@ Bundle saveFragmentBasicState(Fragment f) {
             result.putSparseParcelableArray(
                     FragmentManagerImpl.VIEW_STATE_TAG, f.mSavedViewState);
         }
+        if (!f.mUserVisibleHint) {
+            // Only add this if it's not the default value
+            result.putBoolean(FragmentManagerImpl.USER_VISIBLE_HINT_TAG, f.mUserVisibleHint);
+        }
 
         return result;
     }
