Merge "Lifecycle guarantees for target fragments"

core/java/android/app/Fragment.java

@@ -762,6 +762,24 @@ public class Fragment implements ComponentCallbacks2, OnCreateContextMenuListene
      * are going to call back with {@link #onActivityResult(int, int, Intent)}.
      */
     public void setTargetFragment(Fragment fragment, int requestCode) {
+        // Don't allow a caller to set a target fragment in another FragmentManager,
+        // but there's a snag: people do set target fragments before fragments get added.
+        // We'll have the FragmentManager check that for validity when we move
+        // the fragments to a valid state.
+        final FragmentManager mine = getFragmentManager();
+        final FragmentManager theirs = fragment.getFragmentManager();
+        if (mine != null && theirs != null && mine != theirs) {
+            throw new IllegalArgumentException("Fragment " + fragment
+                    + " must share the same FragmentManager to be set as a target fragment");
+        }
+
+        // Don't let someone create a cycle.
+        for (Fragment check = fragment; check != null; check = check.getTargetFragment()) {
+            if (check == this) {
+                throw new IllegalArgumentException("Setting " + fragment + " as the target of "
+                        + this + " would create a target cycle");
+            }
+        }
         mTarget = fragment;
         mTargetRequestCode = requestCode;
     }

core/java/android/app/FragmentManager.java

@@ -1110,10 +1110,25 @@ final class FragmentManagerImpl extends FragmentManager implements LayoutInflate
                                 }
                             }
                         }
+
                         f.mHost = mHost;
                         f.mParentFragment = mParent;
                         f.mFragmentManager = mParent != null
                                 ? mParent.mChildFragmentManager : mHost.getFragmentManagerImpl();
+
+                        // If we have a target fragment, push it along to at least CREATED
+                        // so that this one can rely on it as an initialized dependency.
+                        if (f.mTarget != null) {
+                            if (!mActive.contains(f.mTarget)) {
+                                throw new IllegalStateException("Fragment " + f
+                                        + " declared target fragment " + f.mTarget
+                                        + " that does not belong to this FragmentManager!");
+                            }
+                            if (f.mTarget.mState < Fragment.CREATED) {
+                                moveToState(f.mTarget, Fragment.CREATED, 0, 0, true);
+                            }
+                        }
+
                         dispatchOnFragmentPreAttached(f, mHost.getContext(), false);
                         f.mCalled = false;
                         f.onAttach(mHost.getContext());