Change the "start deferred" fragment API to "user visible hint"

Allow a fragment to set a hint of whether or not it is currently user
visible. This will be used implicitly to defer the start of fragments
that are not user visible until the loaders for visible fragments have
run. This hint defaults to true.

Change-Id: Id1349d319886a277ef07301f64f7b9e12c8729bf

1 files changed, 36 insertions, 2 deletions

diff --git a/core/java/android/app/FragmentManager.java b/core/java/android/app/FragmentManager.java
index c4ba778..a8c9cba 100644
--- 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 @@ final class FragmentManagerImpl extends FragmentManager {
     
     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 @@ final class FragmentManagerImpl extends FragmentManager {
                             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 @@ final class FragmentManagerImpl extends FragmentManager {
             
             synchronized (this) {
                 if (mPendingActions == null || mPendingActions.size() == 0) {
-                    return didSomething;
+                    break;
                 }
                 
                 numActions = mPendingActions.size();
@@ -1363,8 +1378,23 @@ final class FragmentManagerImpl extends FragmentManager {
             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 @@ final class FragmentManagerImpl extends FragmentManager {
             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;
     }