Enable "offline songs" for both streaming and remote, and have a prompt

if attempting to use it from remote mode. This should be more straight
forward than having it disabled by default.

src/musikdroid/app/src/main/java/io/casey/musikcube/remote/MainActivity.java

@@ -1,12 +1,15 @@
 package io.casey.musikcube.remote;
 
+import android.app.Dialog;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 import android.os.Handler;
 import android.support.design.widget.Snackbar;
+import android.support.v4.app.DialogFragment;
 import android.support.v4.content.ContextCompat;
+import android.support.v7.app.AlertDialog;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
@@ -123,8 +126,6 @@ public class MainActivity extends WebSocketActivityBase {
         menu.findItem(R.id.action_remote_toggle).setIcon(
             streaming ? R.mipmap.ic_toolbar_streaming : R.mipmap.ic_toolbar_remote);
 
-        menu.findItem(R.id.action_offline_tracks).setEnabled(streaming);
-
         return super.onPrepareOptionsMenu(menu);
     }
 
@@ -145,11 +146,11 @@ public class MainActivity extends WebSocketActivityBase {
 
             case R.id.action_playlists:
                 startActivity(CategoryBrowseActivity.getStartIntent(
-                    this, Messages.Category.PLAYLISTS, CategoryBrowseActivity.DeepLink.TRACKS));
+                        this, Messages.Category.PLAYLISTS, CategoryBrowseActivity.DeepLink.TRACKS));
                 return true;
 
             case R.id.action_offline_tracks:
-                startActivity(TrackListActivity.getOfflineStartIntent(this));
+                onOfflineTracksSelected();
                 return true;
         }
 
@@ -166,6 +167,23 @@ public class MainActivity extends WebSocketActivityBase {
         return this.playbackEvents;
     }
 
+    private void onOfflineTracksSelected() {
+        if (isStreamingSelected()) {
+            startActivity(TrackListActivity.getOfflineStartIntent(this));
+        }
+        else {
+            final String tag = SwitchToOfflineTracksDialog.TAG;
+            if (getSupportFragmentManager().findFragmentByTag(tag) == null) {
+                SwitchToOfflineTracksDialog.newInstance().show(getSupportFragmentManager(), tag);
+            }
+        }
+    }
+
+    private void onConfirmSwitchToOfflineTracks() {
+        togglePlaybackService();
+        onOfflineTracksSelected();
+    }
+
     private boolean isStreamingSelected() {
         return prefs.getBoolean(
             Prefs.Key.STREAMING_PLAYBACK,
@@ -438,9 +456,31 @@ public class MainActivity extends WebSocketActivityBase {
         public void onInvalidPassword() {
             final String tag = InvalidPasswordDialogFragment.TAG;
             if (getSupportFragmentManager().findFragmentByTag(tag) == null) {
-                InvalidPasswordDialogFragment
-                    .newInstance().show(getSupportFragmentManager(), tag);
+                InvalidPasswordDialogFragment.newInstance().show(getSupportFragmentManager(), tag);
             }
         }
     };
+
+    public static class SwitchToOfflineTracksDialog extends DialogFragment {
+        public static final String TAG = "switch_to_offline_tracks_dialog";
+
+        public static SwitchToOfflineTracksDialog newInstance() {
+            return new SwitchToOfflineTracksDialog();
+        }
+
+        @Override
+        public Dialog onCreateDialog(Bundle savedInstanceState) {
+            final AlertDialog dlg = new AlertDialog.Builder(getActivity())
+                    .setTitle(R.string.main_switch_to_streaming_title)
+                    .setMessage(R.string.main_switch_to_streaming_message)
+                    .setNegativeButton(R.string.button_no, null)
+                    .setPositiveButton(R.string.button_yes, (dialog, which) -> {
+                        ((MainActivity) getActivity()).onConfirmSwitchToOfflineTracks();
+                    })
+                    .create();
+
+            dlg.setCancelable(false);
+            return dlg;
+        }
+    }
 }

src/musikdroid/app/src/main/java/io/casey/musikcube/remote/playback/PlayerWrapper.kt

@@ -32,8 +32,8 @@ abstract class PlayerWrapper {
         fun onStateChanged(mpw: PlayerWrapper, state: State)
     }
 
-
     private var listener: OnStateChangedListener? = null
+
     var state = State.Stopped
         protected set(state) {
             if (this.state != state) {
@@ -149,9 +149,7 @@ abstract class PlayerWrapper {
 
         fun newInstance(): PlayerWrapper {
             return if (TYPE == Type.ExoPlayer)
-                ExoPlayerWrapper()
-            else
-                MediaPlayerWrapper()
+                ExoPlayerWrapper() else MediaPlayerWrapper()
         }
 
         fun addActivePlayer(player: PlayerWrapper) {

src/musikdroid/app/src/main/java/io/casey/musikcube/remote/ui/activity/TrackListActivity.java

@@ -43,7 +43,7 @@ public class TrackListActivity extends WebSocketActivityBase implements Filterab
 
     public static Intent getOfflineStartIntent(final Context context) {
         return getStartIntent(context, Messages.Category.OFFLINE, 0)
-            .putExtra(Intent.EXTRA_TITLE, R.string.offline_tracks_title);
+            .putExtra(EXTRA_TITLE_ID, R.string.offline_tracks_title);
     }
 
     public static Intent getStartIntent(final Context context,
@@ -75,12 +75,13 @@ public class TrackListActivity extends WebSocketActivityBase implements Filterab
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        categoryType = getIntent().getStringExtra(EXTRA_CATEGORY_TYPE);
-        categoryId = getIntent().getLongExtra(EXTRA_SELECTED_ID, 0);
+        final Intent intent = getIntent();
+        categoryType = intent.getStringExtra(EXTRA_CATEGORY_TYPE);
+        categoryId = intent.getLongExtra(EXTRA_SELECTED_ID, 0);
+        final int titleId = intent.getIntExtra(EXTRA_TITLE_ID, R.string.songs_title);
 
         setContentView(R.layout.recycler_view_activity);
 
-        final int titleId = getIntent().getIntExtra(Intent.EXTRA_TITLE, R.string.songs_title);
         Views.setTitle(this, titleId);
         Views.enableUpNavigation(this);
 

src/musikdroid/app/src/main/res/values/strings.xml

@@ -35,6 +35,8 @@
     <string name="button_enable">enable</string>
     <string name="button_disable">disable</string>
     <string name="button_ok">ok</string>
+    <string name="button_yes">yes</string>
+    <string name="button_no">no</string>
     <string name="button_learn_more">learn more</string>
     <string name="invalid_password_dialog_title">invalid password</string>
     <string name="invalid_password_dialog_message">the server rejected your password.\n\nchange the password in the settings screen.</string>
@@ -58,6 +60,8 @@
     <string name="unknown_value">&lt;unknown&gt;</string>
     <string name="snackbar_streaming_enabled">switched to streaming mode</string>
     <string name="snackbar_remote_enabled">switched to remote control mode</string>
+    <string name="main_switch_to_streaming_title">switch to streaming mode?</string>
+    <string name="main_switch_to_streaming_message">playing offline tracks requires you to switch from remote mode to streaming mode.\n\ndo you want to switch now?</string>
     <string name="settings_playback_mode">playback mode:</string>
     <string name="settings_transcoder_bitrate">streaming downsampler bitrate:</string>
     <string name="settings_cache_size">streaming disk cache size:</string>