altosdroid: Fix tab updates on Android 11 after rotate

[fw/altos] / altosdroid / app / src / main / java / org / altusmetrum / AltosDroid / TabsAdapter.java

diff --git a/altosdroid/app/src/main/java/org/altusmetrum/AltosDroid/TabsAdapter.java b/altosdroid/app/src/main/java/org/altusmetrum/AltosDroid/TabsAdapter.java
index 23d365b4492e06c136e3f008eaf6304adde8d759..0878c011d7c3a39c19d5d113b854567ab8fcb250 100644 (file)
--- a/altosdroid/app/src/main/java/org/altusmetrum/AltosDroid/TabsAdapter.java
+++ b/altosdroid/app/src/main/java/org/altusmetrum/AltosDroid/TabsAdapter.java
@@ -54,10 +54,11 @@ public class TabsAdapter extends FragmentPagerAdapter
                private final Bundle args;
                private Fragment fragment;
 
-               TabInfo(String _tag, Class<?> _class, Bundle _args) {
+               TabInfo(String _tag, Class<?> _class, Bundle _args, Fragment _fragment) {
                        tag = _tag;
                        clss = _class;
                        args = _args;
+                       fragment = _fragment;
                }
        }
 
@@ -86,11 +87,11 @@ public class TabsAdapter extends FragmentPagerAdapter
                mViewPager.addOnPageChangeListener(this);
        }
 
-       public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
+       public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args, Fragment fragment) {
                tabSpec.setContent(new DummyTabFactory(mContext));
                String tag = tabSpec.getTag();
 
-               TabInfo info = new TabInfo(tag, clss, args);
+               TabInfo info = new TabInfo(tag, clss, args, fragment);
                mTabs.add(info);
                mTabHost.addTab(tabSpec);
                notifyDataSetChanged();
@@ -105,7 +106,8 @@ public class TabsAdapter extends FragmentPagerAdapter
        public Fragment getItem(int position) {
                TabInfo info = mTabs.get(position);
                AltosDebug.debug("TabsAdapter.getItem(%d)", position);
-               info.fragment = Fragment.instantiate(mContext, info.clss.getName(), info.args);
+               if (info.fragment == null)
+                       info.fragment = Fragment.instantiate(mContext, info.clss.getName(), info.args);
                return info.fragment;
        }
 
@@ -121,15 +123,19 @@ public class TabsAdapter extends FragmentPagerAdapter
 
                AltosDroidTab   cur_frag = (AltosDroidTab) mTabs.get(position).fragment;
 
+               AltosDebug.debug("TabsAdapter.onTabChanged(%s) = %d cur %s prev %s", tabId, position, cur_frag, prev_frag);
+
                if (prev_frag != cur_frag) {
                        if (prev_frag != null) {
                                prev_frag.set_visible(false);
                        }
                }
-               if (cur_frag != null) {
+
+               /* This happens when the tab is selected before any of them
+                * have been created, like during rotation
+                */
+               if (cur_frag != null)
                        cur_frag.set_visible(true);
-               }
-               AltosDebug.debug("TabsAdapter.onTabChanged(%s) = %d", tabId, position);
                mViewPager.setCurrentItem(position);
        }