add pip backward/forward btns

Closes #2251

Signed-off-by: dom <githubaccount56556@proton.me>

android/app/src/main/java/com/example/piliplus/MediaHelper.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.piliplus;
+
+import android.app.PendingIntent;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.content.pm.ResolveInfo;
+import android.media.session.PlaybackState;
+import android.os.Build;
+import android.util.Log;
+import android.view.KeyEvent;
+
+import java.util.List;
+
+public class MediaHelper {
+    private static final String TAG = "MediaButtonReceiver";
+
+    public static PendingIntent buildMediaButtonPendingIntent(Context context, long action) {
+        ComponentName mbrComponent = getMediaButtonReceiverComponent(context);
+        if (mbrComponent == null) {
+            Log.w(TAG, "A unique media button receiver could not be found in the given context, so "
+                    + "couldn't build a pending intent.");
+            return null;
+        }
+        return buildMediaButtonPendingIntent(context, mbrComponent, action);
+    }
+
+    public static PendingIntent buildMediaButtonPendingIntent(Context context, ComponentName mbrComponent, long action) {
+        if (mbrComponent == null) {
+            Log.w(TAG, "The component name of media button receiver should be provided.");
+            return null;
+        }
+        int keyCode = PlaybackStateCompat_toKeyCode(action);
+        if (keyCode == KeyEvent.KEYCODE_UNKNOWN) {
+            Log.w(TAG,
+                    "Cannot build a media button pending intent with the given action: " + action);
+            return null;
+        }
+        Intent intent = new Intent(Intent.ACTION_MEDIA_BUTTON);
+        intent.setComponent(mbrComponent);
+        intent.putExtra(Intent.EXTRA_KEY_EVENT, new KeyEvent(KeyEvent.ACTION_DOWN, keyCode));
+        intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
+        return PendingIntent.getBroadcast(context, keyCode, intent,
+                Build.VERSION.SDK_INT >= 31 ? PendingIntent.FLAG_MUTABLE : 0);
+    }
+
+    public static int PlaybackStateCompat_toKeyCode(long action) {
+        if (action == PlaybackState.ACTION_PLAY) {
+            return KeyEvent.KEYCODE_MEDIA_PLAY;
+        } else if (action == PlaybackState.ACTION_PAUSE) {
+            return KeyEvent.KEYCODE_MEDIA_PAUSE;
+        } else if (action == PlaybackState.ACTION_SKIP_TO_NEXT) {
+            return KeyEvent.KEYCODE_MEDIA_NEXT;
+        } else if (action == PlaybackState.ACTION_SKIP_TO_PREVIOUS) {
+            return KeyEvent.KEYCODE_MEDIA_PREVIOUS;
+        } else if (action == PlaybackState.ACTION_STOP) {
+            return KeyEvent.KEYCODE_MEDIA_STOP;
+        } else if (action == PlaybackState.ACTION_FAST_FORWARD) {
+            return KeyEvent.KEYCODE_MEDIA_FAST_FORWARD;
+        } else if (action == PlaybackState.ACTION_REWIND) {
+            return KeyEvent.KEYCODE_MEDIA_REWIND;
+        } else if (action == PlaybackState.ACTION_PLAY_PAUSE) {
+            return KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE;
+        }
+        return KeyEvent.KEYCODE_UNKNOWN;
+    }
+
+    public static ComponentName getMediaButtonReceiverComponent(Context context) {
+        Intent queryIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
+        queryIntent.setPackage(context.getPackageName());
+        PackageManager pm = context.getPackageManager();
+        List<ResolveInfo> resolveInfos = pm.queryBroadcastReceivers(queryIntent, 0);
+        if (resolveInfos.size() == 1) {
+            ResolveInfo resolveInfo = resolveInfos.get(0);
+            return new ComponentName(resolveInfo.activityInfo.packageName,
+                    resolveInfo.activityInfo.name);
+        } else if (resolveInfos.size() > 1) {
+            Log.w(TAG, "More than one BroadcastReceiver that handles "
+                    + Intent.ACTION_MEDIA_BUTTON + " was found, returning null.");
+        }
+        return null;
+    }
+}