Inflate fragments from layout into child FragmentManagers

Previously, if an app inflated a layout in a Fragment's onCreateView
that itself had fragments included, those fragments would be added to
the Activity-level FragmentManager and would not share the same
lifecycle with the fragment it was inflated for. This led to some
nasty management headaches.

If an app targets L or above, add the fragment to the child
FragmentManager of the current fragment when inflated using the
LayoutInflater passed to the parent fragment.

Bug 12763389

Change-Id: Iad4ed7d5df602aea9579bf1503e206fa894630c1

3 files changed, 112 insertions, 75 deletions

diff --git a/core/java/android/app/Activity.java b/core/java/android/app/Activity.java
index d0d0289..83cbaa1 100644
--- a/core/java/android/app/Activity.java
+++ b/core/java/android/app/Activity.java
@@ -5139,78 +5139,7 @@ public class Activity extends ContextThemeWrapper
             return onCreateView(name, context, attrs);
         }
         
-        String fname = attrs.getAttributeValue(null, "class");
-        TypedArray a = 
-            context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.Fragment);
-        if (fname == null) {
-            fname = a.getString(com.android.internal.R.styleable.Fragment_name);
-        }
-        int id = a.getResourceId(com.android.internal.R.styleable.Fragment_id, View.NO_ID);
-        String tag = a.getString(com.android.internal.R.styleable.Fragment_tag);
-        a.recycle();
-        
-        int containerId = parent != null ? parent.getId() : 0;
-        if (containerId == View.NO_ID && id == View.NO_ID && tag == null) {
-            throw new IllegalArgumentException(attrs.getPositionDescription()
-                    + ": Must specify unique android:id, android:tag, or have a parent with an id for " + fname);
-        }
-
-        // If we restored from a previous state, we may already have
-        // instantiated this fragment from the state and should use
-        // that instance instead of making a new one.
-        Fragment fragment = id != View.NO_ID ? mFragments.findFragmentById(id) : null;
-        if (fragment == null && tag != null) {
-            fragment = mFragments.findFragmentByTag(tag);
-        }
-        if (fragment == null && containerId != View.NO_ID) {
-            fragment = mFragments.findFragmentById(containerId);
-        }
-
-        if (FragmentManagerImpl.DEBUG) Log.v(TAG, "onCreateView: id=0x"
-                + Integer.toHexString(id) + " fname=" + fname
-                + " existing=" + fragment);
-        if (fragment == null) {
-            fragment = Fragment.instantiate(this, fname);
-            fragment.mFromLayout = true;
-            fragment.mFragmentId = id != 0 ? id : containerId;
-            fragment.mContainerId = containerId;
-            fragment.mTag = tag;
-            fragment.mInLayout = true;
-            fragment.mFragmentManager = mFragments;
-            fragment.onInflate(this, attrs, fragment.mSavedFragmentState);
-            mFragments.addFragment(fragment, true);
-
-        } else if (fragment.mInLayout) {
-            // A fragment already exists and it is not one we restored from
-            // previous state.
-            throw new IllegalArgumentException(attrs.getPositionDescription()
-                    + ": Duplicate id 0x" + Integer.toHexString(id)
-                    + ", tag " + tag + ", or parent id 0x" + Integer.toHexString(containerId)
-                    + " with another fragment for " + fname);
-        } else {
-            // This fragment was retained from a previous instance; get it
-            // going now.
-            fragment.mInLayout = true;
-            // If this fragment is newly instantiated (either right now, or
-            // from last saved state), then give it the attributes to
-            // initialize itself.
-            if (!fragment.mRetaining) {
-                fragment.onInflate(this, attrs, fragment.mSavedFragmentState);
-            }
-            mFragments.moveToState(fragment);
-        }
-
-        if (fragment.mView == null) {
-            throw new IllegalStateException("Fragment " + fname
-                    + " did not create a view.");
-        }
-        if (id != 0) {
-            fragment.mView.setId(id);
-        }
-        if (fragment.mView.getTag() == null) {
-            fragment.mView.setTag(tag);
-        }
-        return fragment.mView;
+        return mFragments.onCreateView(parent, name, context, attrs);
     }
 
     /**
diff --git a/core/java/android/app/Fragment.java b/core/java/android/app/Fragment.java
index 6c0d379..2ff3d57 100644
--- a/core/java/android/app/Fragment.java
+++ b/core/java/android/app/Fragment.java
@@ -23,6 +23,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.res.Configuration;
 import android.content.res.Resources;
+import android.os.Build;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
@@ -1104,7 +1105,15 @@ public class Fragment implements ComponentCallbacks2, OnCreateContextMenuListene
      * inflation.  Maybe this should become a public API. Note sure.
      */
     public LayoutInflater getLayoutInflater(Bundle savedInstanceState) {
-        return mActivity.getLayoutInflater();
+        // Newer platform versions use the child fragment manager's LayoutInflaterFactory.
+        if (mActivity.getApplicationInfo().targetSdkVersion >= Build.VERSION_CODES.L) {
+            LayoutInflater result = mActivity.getLayoutInflater().cloneInContext(mActivity);
+            getChildFragmentManager(); // Init if needed; use raw implementation below.
+            result.setPrivateFactory(mChildFragmentManager.getLayoutInflaterFactory());
+            return result;
+        } else {
+            return mActivity.getLayoutInflater();
+        }
     }
     
     /**
diff --git a/core/java/android/app/FragmentManager.java b/core/java/android/app/FragmentManager.java
index b8f1962..a97fa65 100644
--- a/core/java/android/app/FragmentManager.java
+++ b/core/java/android/app/FragmentManager.java
@@ -19,6 +19,7 @@ package android.app;
 import android.animation.Animator;
 import android.animation.AnimatorInflater;
 import android.animation.AnimatorListenerAdapter;
+import android.content.Context;
 import android.content.res.Configuration;
 import android.content.res.TypedArray;
 import android.os.Bundle;
@@ -27,11 +28,13 @@ import android.os.Handler;
 import android.os.Looper;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.util.AttributeSet;
 import android.util.DebugUtils;
 import android.util.Log;
 import android.util.LogWriter;
 import android.util.SparseArray;
 import android.util.SuperNotCalledException;
+import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
@@ -397,7 +400,7 @@ interface FragmentContainer {
 /**
  * Container for fragments associated with an activity.
  */
-final class FragmentManagerImpl extends FragmentManager {
+final class FragmentManagerImpl extends FragmentManager implements LayoutInflater.Factory2 {
     static boolean DEBUG = false;
     static final String TAG = "FragmentManager";
     
@@ -432,7 +435,7 @@ final class FragmentManagerImpl extends FragmentManager {
     boolean mDestroyed;
     String mNoTransactionsBecause;
     boolean mHavePendingDeferredStart;
-    
+
     // Temporary vars for state save and restore.
     Bundle mStateBundle = null;
     SparseArray<Parcelable> mStateArray = null;
@@ -2052,4 +2055,100 @@ final class FragmentManagerImpl extends FragmentManager {
         }
         return animAttr;
     }
+
+    @Override
+    public View onCreateView(View parent, String name, Context context, AttributeSet attrs) {
+        if (!"fragment".equals(name)) {
+            return null;
+        }
+
+        String fname = attrs.getAttributeValue(null, "class");
+        TypedArray a =
+                context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.Fragment);
+        if (fname == null) {
+            fname = a.getString(com.android.internal.R.styleable.Fragment_name);
+        }
+        int id = a.getResourceId(com.android.internal.R.styleable.Fragment_id, View.NO_ID);
+        String tag = a.getString(com.android.internal.R.styleable.Fragment_tag);
+        a.recycle();
+
+        int containerId = parent != null ? parent.getId() : 0;
+        if (containerId == View.NO_ID && id == View.NO_ID && tag == null) {
+            throw new IllegalArgumentException(attrs.getPositionDescription()
+                    + ": Must specify unique android:id, android:tag, or have a parent with"
+                    + " an id for " + fname);
+        }
+
+        // If we restored from a previous state, we may already have
+        // instantiated this fragment from the state and should use
+        // that instance instead of making a new one.
+        Fragment fragment = id != View.NO_ID ? findFragmentById(id) : null;
+        if (fragment == null && tag != null) {
+            fragment = findFragmentByTag(tag);
+        }
+        if (fragment == null && containerId != View.NO_ID) {
+            fragment = findFragmentById(containerId);
+        }
+
+        if (FragmentManagerImpl.DEBUG) Log.v(TAG, "onCreateView: id=0x"
+                + Integer.toHexString(id) + " fname=" + fname
+                + " existing=" + fragment);
+        if (fragment == null) {
+            fragment = Fragment.instantiate(context, fname);
+            fragment.mFromLayout = true;
+            fragment.mFragmentId = id != 0 ? id : containerId;
+            fragment.mContainerId = containerId;
+            fragment.mTag = tag;
+            fragment.mInLayout = true;
+            fragment.mFragmentManager = this;
+            fragment.onInflate(mActivity, attrs, fragment.mSavedFragmentState);
+            addFragment(fragment, true);
+        } else if (fragment.mInLayout) {
+            // A fragment already exists and it is not one we restored from
+            // previous state.
+            throw new IllegalArgumentException(attrs.getPositionDescription()
+                    + ": Duplicate id 0x" + Integer.toHexString(id)
+                    + ", tag " + tag + ", or parent id 0x" + Integer.toHexString(containerId)
+                    + " with another fragment for " + fname);
+        } else {
+            // This fragment was retained from a previous instance; get it
+            // going now.
+            fragment.mInLayout = true;
+            // If this fragment is newly instantiated (either right now, or
+            // from last saved state), then give it the attributes to
+            // initialize itself.
+            if (!fragment.mRetaining) {
+                fragment.onInflate(mActivity, attrs, fragment.mSavedFragmentState);
+            }
+        }
+
+        // If we haven't finished entering the CREATED state ourselves yet,
+        // push the inflated child fragment along.
+        if (mCurState < Fragment.CREATED && fragment.mFromLayout) {
+            moveToState(fragment, Fragment.CREATED, 0, 0, false);
+        } else {
+            moveToState(fragment);
+        }
+
+        if (fragment.mView == null) {
+            throw new IllegalStateException("Fragment " + fname
+                    + " did not create a view.");
+        }
+        if (id != 0) {
+            fragment.mView.setId(id);
+        }
+        if (fragment.mView.getTag() == null) {
+            fragment.mView.setTag(tag);
+        }
+        return fragment.mView;
+    }
+
+    @Override
+    public View onCreateView(String name, Context context, AttributeSet attrs) {
+        return null;
+    }
+
+    LayoutInflater.Factory2 getLayoutInflaterFactory() {
+        return this;
+    }
 }