Fix issue #6675499: java.lang.RuntimeException: Unable to start...

...activity ComponentInfo{com.google.android.gm/
com.google.android.gm.ui.MailActivityGmail}: java.lang.NullPointerException

There were a number of places in FragmentManagerImpl where we were
not dealing with mAdded being null.  In the original implementation,
mAdded would almost always be null if mActive is null.  As we have
added features, this has become a less strong guarantee (and it actually
was never completely guaranteed), but there are a lot of places where
we would check for mActive being non-null and assume this meant
mAdded is non-null.

Fix these to correctly check for mAdded.

Bug: 6675499
Change-Id: I2a6a801d8bc89550fc73e12c9c3f8bb0ad6c7fa4

Author: Dianne Hackborn

core/java/android/app/FragmentManager.java

@@ -1118,7 +1118,9 @@ public void removeFragment(Fragment fragment, int transition, int transitionStyl
         if (DEBUG) Log.v(TAG, "remove: " + fragment + " nesting=" + fragment.mBackStackNesting);
         final boolean inactive = !fragment.isInBackStack();
         if (!fragment.mDetached || inactive) {
-            mAdded.remove(fragment);
+            if (mAdded != null) {
+                mAdded.remove(fragment);
+            }
             if (fragment.mHasMenu && fragment.mMenuVisible) {
                 mNeedMenuInvalidate = true;
             }
@@ -1187,7 +1189,9 @@ public void detachFragment(Fragment fragment, int transition, int transitionStyl
             fragment.mDetached = true;
             if (fragment.mAdded) {
                 // We are not already in back stack, so need to remove the fragment.
-                mAdded.remove(fragment);
+                if (mAdded != null) {
+                    mAdded.remove(fragment);
+                }
                 if (fragment.mHasMenu && fragment.mMenuVisible) {
                     mNeedMenuInvalidate = true;
                 }
@@ -1202,6 +1206,9 @@ public void attachFragment(Fragment fragment, int transition, int transitionStyl
         if (fragment.mDetached) {
             fragment.mDetached = false;
             if (!fragment.mAdded) {
+                if (mAdded == null) {
+                    mAdded = new ArrayList<Fragment>();
+                }
                 mAdded.add(fragment);
                 fragment.mAdded = true;
                 if (fragment.mHasMenu && fragment.mMenuVisible) {
@@ -1213,14 +1220,16 @@ public void attachFragment(Fragment fragment, int transition, int transitionStyl
     }
 
     public Fragment findFragmentById(int id) {
-        if (mActive != null) {
+        if (mAdded != null) {
             // First look through added fragments.
             for (int i=mAdded.size()-1; i>=0; i--) {
                 Fragment f = mAdded.get(i);
                 if (f != null && f.mFragmentId == id) {
                     return f;
                 }
             }
+        }
+        if (mActive != null) {
             // Now for any known fragment.
             for (int i=mActive.size()-1; i>=0; i--) {
                 Fragment f = mActive.get(i);
@@ -1233,14 +1242,16 @@ public Fragment findFragmentById(int id) {
     }
 
     public Fragment findFragmentByTag(String tag) {
-        if (mActive != null && tag != null) {
+        if (mAdded != null && tag != null) {
             // First look through added fragments.
             for (int i=mAdded.size()-1; i>=0; i--) {
                 Fragment f = mAdded.get(i);
                 if (f != null && tag.equals(f.mTag)) {
                     return f;
                 }
             }
+        }
+        if (mActive != null && tag != null) {
             // Now for any known fragment.
             for (int i=mActive.size()-1; i>=0; i--) {
                 Fragment f = mActive.get(i);
@@ -1817,7 +1828,7 @@ public void dispatchDestroy() {
     }
 
     public void dispatchConfigurationChanged(Configuration newConfig) {
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null) {
@@ -1828,7 +1839,7 @@ public void dispatchConfigurationChanged(Configuration newConfig) {
     }
 
     public void dispatchLowMemory() {
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null) {
@@ -1839,7 +1850,7 @@ public void dispatchLowMemory() {
     }
 
     public void dispatchTrimMemory(int level) {
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null) {
@@ -1852,7 +1863,7 @@ public void dispatchTrimMemory(int level) {
     public boolean dispatchCreateOptionsMenu(Menu menu, MenuInflater inflater) {
         boolean show = false;
         ArrayList<Fragment> newMenus = null;
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null && !f.mHidden && f.mHasMenu && f.mMenuVisible) {
@@ -1882,7 +1893,7 @@ public boolean dispatchCreateOptionsMenu(Menu menu, MenuInflater inflater) {
 
     public boolean dispatchPrepareOptionsMenu(Menu menu) {
         boolean show = false;
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null && !f.mHidden && f.mHasMenu && f.mMenuVisible) {
@@ -1895,7 +1906,7 @@ public boolean dispatchPrepareOptionsMenu(Menu menu) {
     }
 
     public boolean dispatchOptionsItemSelected(MenuItem item) {
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null && !f.mHidden && f.mHasMenu && f.mMenuVisible) {
@@ -1909,7 +1920,7 @@ public boolean dispatchOptionsItemSelected(MenuItem item) {
     }
 
     public boolean dispatchContextItemSelected(MenuItem item) {
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null && !f.mHidden && f.mUserVisibleHint) {
@@ -1923,7 +1934,7 @@ public boolean dispatchContextItemSelected(MenuItem item) {
     }
 
     public void dispatchOptionsMenuClosed(Menu menu) {
-        if (mActive != null) {
+        if (mAdded != null) {
             for (int i=0; i<mAdded.size(); i++) {
                 Fragment f = mAdded.get(i);
                 if (f != null && !f.mHidden && f.mHasMenu && f.mMenuVisible) {