Android: Update cheat list when a cheat is edited

The way I'm implementing events using LiveData feels rather
unorthodox, but I'm not aware of anything in the Android framework
that would let me do it in a better way... One option I did
consider was wrapping the cheat lists in LiveData and observing
those, but then CheatsAdapter wouldn't know which cheat had
changed, only that there was some kind of change to the list,
necessitating the use of the not recommended notifyDataSetChanged.

5 files changed, 46 insertions, 6 deletions

diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/model/CheatsViewModel.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/model/CheatsViewModel.java
index e4e5298104..cdd68221c6 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/model/CheatsViewModel.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/model/CheatsViewModel.java
@@ -10,9 +10,11 @@ public class CheatsViewModel extends ViewModel
 {
   private boolean mLoaded = false;
 
+  private int mSelectedCheatPosition = -1;
   private final MutableLiveData<Cheat> mSelectedCheat = new MutableLiveData<>(null);
   private final MutableLiveData<Boolean> mIsEditing = new MutableLiveData<>(false);
 
+  private final MutableLiveData<Integer> mCheatChangedEvent = new MutableLiveData<>(null);
   private final MutableLiveData<Boolean> mOpenDetailsViewEvent = new MutableLiveData<>(false);
 
   private PatchCheat[] mPatchCheats;
@@ -74,12 +76,13 @@ public class CheatsViewModel extends ViewModel
     return mSelectedCheat;
   }
 
-  public void setSelectedCheat(Cheat cheat)
+  public void setSelectedCheat(Cheat cheat, int position)
   {
     if (mIsEditing.getValue())
       setIsEditing(false);
 
     mSelectedCheat.setValue(cheat);
+    mSelectedCheatPosition = position;
   }
 
   public LiveData<Boolean> getIsEditing()
@@ -92,6 +95,32 @@ public class CheatsViewModel extends ViewModel
     mIsEditing.setValue(isEditing);
   }
 
+  /**
+   * When a cheat is edited, the integer stored in the returned LiveData
+   * changes to the position of that cheat, then changes back to null.
+   */
+  public LiveData<Integer> getCheatChangedEvent()
+  {
+    return mCheatChangedEvent;
+  }
+
+  /**
+   * Notifies that an edit has been made to the contents of the currently selected cheat.
+   */
+  public void notifySelectedCheatChanged()
+  {
+    notifyCheatChanged(mSelectedCheatPosition);
+  }
+
+  /**
+   * Notifies that an edit has been made to the contents of the cheat at the given position.
+   */
+  public void notifyCheatChanged(int position)
+  {
+    mCheatChangedEvent.setValue(position);
+    mCheatChangedEvent.setValue(null);
+  }
+
   public LiveData<Boolean> getOpenDetailsViewEvent()
   {
     return mOpenDetailsViewEvent;
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatDetailsFragment.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatDetailsFragment.java
index 0b7ce49785..3a61b2e4b7 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatDetailsFragment.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatDetailsFragment.java
@@ -76,6 +76,7 @@ public class CheatDetailsFragment extends Fragment
     switch (result)
     {
       case Cheat.TRY_SET_SUCCESS:
+        mViewModel.notifySelectedCheatChanged();
         mViewModel.setIsEditing(false);
         break;
       case Cheat.TRY_SET_FAIL_NO_NAME:
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatListFragment.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatListFragment.java
index 82c5b549bb..03f87f0c0c 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatListFragment.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatListFragment.java
@@ -36,7 +36,7 @@ public class CheatListFragment extends Fragment
     CheatsActivity activity = (CheatsActivity) requireActivity();
     CheatsViewModel viewModel = new ViewModelProvider(activity).get(CheatsViewModel.class);
 
-    recyclerView.setAdapter(new CheatsAdapter(viewModel));
+    recyclerView.setAdapter(new CheatsAdapter(getViewLifecycleOwner(), viewModel));
     recyclerView.setLayoutManager(new LinearLayoutManager(activity));
     recyclerView.addItemDecoration(new DividerItemDecoration(activity, null));
   }
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatViewHolder.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatViewHolder.java
index c48c7c27be..1ffcafafd5 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatViewHolder.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatViewHolder.java
@@ -23,6 +23,7 @@ public class CheatViewHolder extends ViewHolder
 
   private CheatsViewModel mViewModel;
   private Cheat mCheat;
+  private int mPosition;
 
   public CheatViewHolder(@NonNull View itemView)
   {
@@ -33,7 +34,7 @@ public class CheatViewHolder extends ViewHolder
     mCheckbox = itemView.findViewById(R.id.checkbox);
   }
 
-  public void bind(CheatsViewModel viewModel, Cheat item)
+  public void bind(CheatsViewModel viewModel, Cheat item, int position)
   {
     mCheckbox.setOnCheckedChangeListener(null);
 
@@ -42,6 +43,7 @@ public class CheatViewHolder extends ViewHolder
 
     mViewModel = viewModel;
     mCheat = item;
+    mPosition = position;
 
     mRoot.setOnClickListener(this);
     mCheckbox.setOnCheckedChangeListener(this);
@@ -49,12 +51,13 @@ public class CheatViewHolder extends ViewHolder
 
   public void onClick(View root)
   {
-    mViewModel.setSelectedCheat(mCheat);
+    mViewModel.setSelectedCheat(mCheat, mPosition);
     mViewModel.openDetailsView();
   }
 
   public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)
   {
     mCheat.setEnabled(isChecked);
+    mViewModel.notifyCheatChanged(mPosition);
   }
 }
diff --git a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatsAdapter.java b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatsAdapter.java
index 3638ab383f..623f89c507 100644
--- a/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatsAdapter.java
+++ b/Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/cheats/ui/CheatsAdapter.java
@@ -7,6 +7,7 @@ import android.view.View;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
+import androidx.lifecycle.LifecycleOwner;
 import androidx.recyclerview.widget.RecyclerView;
 
 import org.dolphinemu.dolphinemu.R;
@@ -17,9 +18,15 @@ public class CheatsAdapter extends RecyclerView.Adapter<CheatViewHolder>
 {
   private final CheatsViewModel mViewModel;
 
-  public CheatsAdapter(CheatsViewModel viewModel)
+  public CheatsAdapter(LifecycleOwner owner, CheatsViewModel viewModel)
   {
     mViewModel = viewModel;
+
+    mViewModel.getCheatChangedEvent().observe(owner, (position) ->
+    {
+      if (position != null)
+        notifyItemChanged(position);
+    });
   }
 
   @NonNull
@@ -34,7 +41,7 @@ public class CheatsAdapter extends RecyclerView.Adapter<CheatViewHolder>
   @Override
   public void onBindViewHolder(@NonNull CheatViewHolder holder, int position)
   {
-    holder.bind(mViewModel, getItemAt(position));
+    holder.bind(mViewModel, getItemAt(position), position);
   }
 
   @Override