ProfileFragment: Helper class to remember a fragment's profile

Caching the actual profile object is important when the fragment is on
an activity's back stack: when it is shown again, onCreateView will be
called with profile already set and the service already connected. In
this case, there is no later notification from which to bind the
profile, so the existing object needs to be bound there.

2 files changed, 62 insertions, 16 deletions

diff --git a/app/src/main/java/com/wireguard/android/ProfileDetailFragment.java b/app/src/main/java/com/wireguard/android/ProfileDetailFragment.java
index 4af7fb25..2aa40c06 100644
--- a/app/src/main/java/com/wireguard/android/ProfileDetailFragment.java
+++ b/app/src/main/java/com/wireguard/android/ProfileDetailFragment.java
@@ -10,22 +10,15 @@ import android.view.ViewGroup;
 import com.wireguard.android.databinding.ProfileDetailFragmentBinding;
 
 /**
- * Fragment for viewing and editing a WireGuard profile.
+ * Fragment for viewing information about a WireGuard profile.
  */
 
-public class ProfileDetailFragment extends ServiceClientFragment<ProfileServiceInterface> {
+public class ProfileDetailFragment extends ProfileFragment {
     private ProfileDetailFragmentBinding binding;
-    private String name;
-
-    public ProfileDetailFragment() {
-        super();
-        setArguments(new Bundle());
-    }
 
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        name = getArguments().getString(ProfileActivity.KEY_PROFILE_NAME);
         setHasOptionsMenu(true);
     }
 
@@ -37,20 +30,20 @@ public class ProfileDetailFragment extends ServiceClientFragment<ProfileServiceI
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState) {
         binding = ProfileDetailFragmentBinding.inflate(inflater, parent, false);
+        binding.setProfile(getCachedProfile());
         return binding.getRoot();
     }
 
     @Override
     public void onServiceConnected(ProfileServiceInterface service) {
         super.onServiceConnected(service);
-        binding.setProfile(service.getProfiles().get(name));
+        binding.setProfile(service.getProfiles().get(getProfile()));
     }
 
-    public void setProfile(String name) {
-        this.name = name;
-        getArguments().putString(ProfileActivity.KEY_PROFILE_NAME, name);
-        final ProfileServiceInterface service = getService();
-        if (binding != null && service != null)
-            binding.setProfile(service.getProfiles().get(name));
+    @Override
+    public void setProfile(String profile) {
+        super.setProfile(profile);
+        if (binding != null)
+            binding.setProfile(getCachedProfile());
     }
 }
diff --git a/app/src/main/java/com/wireguard/android/ProfileFragment.java b/app/src/main/java/com/wireguard/android/ProfileFragment.java
new file mode 100644
index 00000000..cf1c690e
--- /dev/null
+++ b/app/src/main/java/com/wireguard/android/ProfileFragment.java
@@ -0,0 +1,53 @@
+package com.wireguard.android;
+
+import android.os.Bundle;
+
+import com.wireguard.config.Profile;
+
+/**
+ * Base class for fragments that need to remember which profile they belong to.
+ */
+
+abstract class ProfileFragment extends ServiceClientFragment<ProfileServiceInterface> {
+    private Profile cachedProfile;
+    private String profile;
+
+    protected Profile getCachedProfile() {
+        return cachedProfile;
+    }
+
+    public String getProfile() {
+        return profile;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        // Restore the saved profile if there is one; otherwise grab it from the arguments.
+        if (savedInstanceState != null)
+            profile = savedInstanceState.getString(ProfileActivity.KEY_PROFILE_NAME);
+        else if (getArguments() != null)
+            profile = getArguments().getString(ProfileActivity.KEY_PROFILE_NAME);
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+        outState.putString(ProfileActivity.KEY_PROFILE_NAME, profile);
+    }
+
+    @Override
+    public void onServiceConnected(ProfileServiceInterface service) {
+        super.onServiceConnected(service);
+        cachedProfile = service.getProfiles().get(profile);
+    }
+
+    public void setProfile(String profile) {
+        this.profile = profile;
+        final ProfileServiceInterface service = getService();
+        if (service != null)
+            cachedProfile = service.getProfiles().get(profile);
+        else
+            cachedProfile = null;
+    }
+}