Android: Implement disc changing via playlists

android/app/src/cpp/android_host_interface.cpp

@@ -28,6 +28,7 @@ Log_SetChannel(AndroidHostInterface);
 #endif
 
 static JavaVM* s_jvm;
+static jclass s_String_class;
 static jclass s_AndroidHostInterface_class;
 static jmethodID s_AndroidHostInterface_constructor;
 static jfieldID s_AndroidHostInterface_field_mNativePointer;
@@ -618,7 +619,10 @@ extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved)
 
   // Create global reference so it doesn't get cleaned up.
   JNIEnv* env = AndroidHelpers::GetJNIEnv();
-  if ((s_AndroidHostInterface_class = env->FindClass("com/github/stenzek/duckstation/AndroidHostInterface")) ==
+  if ((s_String_class = env->FindClass("java/lang/String")) == nullptr ||
+      (s_String_class = static_cast<jclass>(env->NewGlobalRef(s_String_class))) ==
+      nullptr ||
+      (s_AndroidHostInterface_class = env->FindClass("com/github/stenzek/duckstation/AndroidHostInterface")) ==
         nullptr ||
       (s_AndroidHostInterface_class = static_cast<jclass>(env->NewGlobalRef(s_AndroidHostInterface_class))) ==
         nullptr ||
@@ -1011,3 +1015,46 @@ DEFINE_JNI_ARGS_METHOD(jstring, AndroidHostInterface_importBIOSImage, jobject ob
   else
     return env->NewStringUTF(hash.ToString().c_str());
 }
+
+DEFINE_JNI_ARGS_METHOD(jobjectArray, AndroidHostInterface_getMediaPlaylistPaths, jobject obj)
+{
+  if (!System::IsValid())
+    return nullptr;
+
+  const u32 count = System::GetMediaPlaylistCount();
+  if (count == 0)
+    return nullptr;
+
+  jobjectArray arr = env->NewObjectArray(static_cast<jsize>(count), s_String_class, nullptr);
+  for (u32 i = 0; i < count; i++)
+  {
+    jstring str = env->NewStringUTF(System::GetMediaPlaylistPath(i).c_str());
+    env->SetObjectArrayElement(arr, static_cast<jsize>(i), str);
+  }
+
+  return arr;
+}
+
+DEFINE_JNI_ARGS_METHOD(jint, AndroidHostInterface_getMediaPlaylistIndex, jobject obj)
+{
+  if (!System::IsValid())
+    return -1;
+
+  return System::GetMediaPlaylistIndex();
+}
+
+DEFINE_JNI_ARGS_METHOD(jboolean, AndroidHostInterface_setMediaPlaylistIndex, jobject obj, jint index)
+{
+  if (!System::IsValid() || index < 0 || static_cast<u32>(index) >= System::GetMediaPlaylistCount())
+    return false;
+
+  AndroidHostInterface* hi = AndroidHelpers::GetNativeClass(env, obj);
+  hi->RunOnEmulationThread([index, hi]() {
+    if (System::IsValid()) {
+      if (!System::SwitchMediaFromPlaylist(index))
+        hi->AddOSDMessage("Disc switch failed. Please make sure the file exists.");
+    }
+  });
+
+  return true;
+}

android/app/src/main/java/com/github/stenzek/duckstation/AndroidHostInterface.java

@@ -83,6 +83,10 @@ public class AndroidHostInterface {
     public native boolean isFastForwardEnabled();
     public native void setFastForwardEnabled(boolean enabled);
 
+    public native String[] getMediaPlaylistPaths();
+    public native int getMediaPlaylistIndex();
+    public native boolean setMediaPlaylistIndex(int index);
+
     static {
         System.loadLibrary("duckstation-native");
     }

android/app/src/main/java/com/github/stenzek/duckstation/EmulationActivity.java

@@ -409,7 +409,7 @@ public class EmulationActivity extends AppCompatActivity implements SurfaceHolde
 
                 case 2:     // Change Disc
                 {
-                    onMenuClosed();
+                    showDiscChangeMenu();
                     return;
                 }
 
@@ -482,6 +482,30 @@ public class EmulationActivity extends AppCompatActivity implements SurfaceHolde
         }
     }
 
+    private void showDiscChangeMenu() {
+        final String[] paths = AndroidHostInterface.getInstance().getMediaPlaylistPaths();
+        final int currentPath = AndroidHostInterface.getInstance().getMediaPlaylistIndex();
+        if (paths == null)
+        {
+            onMenuClosed();
+            return;
+        }
+
+        AlertDialog.Builder builder = new AlertDialog.Builder(this);
+
+        CharSequence[] items = new CharSequence[paths.length];
+        for (int i = 0; i < paths.length; i++)
+            items[i] = GameListEntry.getFileNameForPath(paths[i]);
+
+        builder.setSingleChoiceItems(items, currentPath, (dialogInterface, i) -> {
+            AndroidHostInterface.getInstance().setMediaPlaylistIndex(i);
+            dialogInterface.dismiss();
+            onMenuClosed();
+        });
+        builder.setOnCancelListener(dialogInterface -> onMenuClosed());
+        builder.create().show();
+    }
+
     /**
      * Touchscreen controller overlay
      */

android/app/src/main/java/com/github/stenzek/duckstation/GameListEntry.java

@@ -9,7 +9,8 @@ import androidx.core.content.ContextCompat;
 public class GameListEntry {
     public enum EntryType {
         Disc,
-        PSExe
+        PSExe,
+        Playlist
     }
 
     public enum CompatibilityRating {
@@ -90,15 +91,17 @@ public class GameListEntry {
         return mCompatibilityRating;
     }
 
-    private String getSubTitle() {
-        String sizeString = String.format("%.2f MB", (double) mSize / 1048576.0);
-        String fileName;
-        int lastSlash = mPath.lastIndexOf('/');
-        if (lastSlash > 0 && lastSlash < mPath.length() - 1)
-            fileName = mPath.substring(lastSlash + 1);
+    public static String getFileNameForPath(String path) {
+        int lastSlash = path.lastIndexOf('/');
+        if (lastSlash > 0 && lastSlash < path.length() - 1)
+            return path.substring(lastSlash + 1);
         else
-            fileName = mPath;
+            return path;
+    }
 
+    private String getSubTitle() {
+        String fileName = getFileNameForPath(mPath);
+        String sizeString = String.format("%.2f MB", (double) mSize / 1048576.0);
         return String.format("%s (%s)", fileName, sizeString);
     }
 
@@ -134,6 +137,10 @@ public class GameListEntry {
             case PSExe:
                 typeDrawableId = R.drawable.ic_emblem_system;
                 break;
+
+            case Playlist:
+                typeDrawableId = R.drawable.ic_baseline_playlist_play_24;
+                break;
         }
 
         ((ImageView) view.findViewById(R.id.game_list_view_entry_type_icon))

android/app/src/main/res/drawable/ic_baseline_playlist_play_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorControlNormal">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M4,10h12v2L4,12zM4,6h12v2L4,8zM4,14h8v2L4,16zM14,14v6l5,-3z"/>
+</vector>

src/frontend-common/game_list.cpp

@@ -25,7 +25,7 @@ GameList::~GameList() = default;
 
 const char* GameList::EntryTypeToString(GameListEntryType type)
 {
-  static std::array<const char*, 2> names = {{"Disc", "PSExe"}};
+  static std::array<const char*, 3> names = {{"Disc", "PSExe", "Playlist"}};
   return names[static_cast<int>(type)];
 }