create new threads only when needed

app/src/main/kotlin/com/simplemobiletools/musicplayer/activities/MainActivity.kt

@@ -19,10 +19,7 @@ import androidx.core.view.MenuItemCompat
 import com.simplemobiletools.commons.dialogs.FilePickerDialog
 import com.simplemobiletools.commons.dialogs.RadioGroupDialog
 import com.simplemobiletools.commons.extensions.*
-import com.simplemobiletools.commons.helpers.LICENSE_OTTO
-import com.simplemobiletools.commons.helpers.LICENSE_PICASSO
-import com.simplemobiletools.commons.helpers.PERMISSION_WRITE_STORAGE
-import com.simplemobiletools.commons.helpers.REAL_FILE_PATH
+import com.simplemobiletools.commons.helpers.*
 import com.simplemobiletools.commons.interfaces.RecyclerScrollCallback
 import com.simplemobiletools.commons.models.FAQItem
 import com.simplemobiletools.commons.models.FileDirItem
@@ -341,11 +338,11 @@ class MainActivity : SimpleActivity(), SongListListener {
         if (config.currentPlaylist == ALL_SONGS_PLAYLIST_ID) {
             toast(R.string.all_songs_cannot_be_deleted)
         } else {
-            Thread {
+            ensureBackgroundThread {
                 val playlist = playlistDAO.getPlaylistWithId(config.currentPlaylist)
                 runOnUiThread {
                     RemovePlaylistDialog(this, playlist) {
-                        Thread {
+                        ensureBackgroundThread {
                             if (it) {
                                 val paths = getPlaylistSongs(config.currentPlaylist).map { it.path }
                                 val files = paths.map { FileDirItem(it, it.getFilenameFromPath()) } as ArrayList<FileDirItem>
@@ -359,20 +356,20 @@ class MainActivity : SimpleActivity(), SongListListener {
                                 deletePlaylists(arrayListOf(playlist))
                             }
                             playlistChanged(ALL_SONGS_PLAYLIST_ID)
-                        }.start()
+                        }
                     }
                 }
-            }.start()
+            }
         }
     }
 
     private fun openPlaylist() {
-        Thread {
+        ensureBackgroundThread {
             val playlists = playlistDAO.getAll() as ArrayList<Playlist>
             runOnUiThread {
                 showPlaylists(playlists)
             }
-        }.start()
+        }
     }
 
     private fun showPlaylists(playlists: ArrayList<Playlist>) {
@@ -399,11 +396,11 @@ class MainActivity : SimpleActivity(), SongListListener {
     private fun addFolderToPlaylist() {
         FilePickerDialog(this, getFilePickerInitialPath(), pickFile = false) {
             toast(R.string.fetching_songs)
-            Thread {
+            ensureBackgroundThread {
                 val folderSongs = getFolderSongs(File(it))
                 RoomHelper(applicationContext).addSongsToPlaylist(folderSongs)
                 sendIntent(REFRESH_LIST)
-            }.start()
+            }
         }
     }
 
@@ -423,7 +420,7 @@ class MainActivity : SimpleActivity(), SongListListener {
 
     private fun addFileToPlaylist() {
         FilePickerDialog(this, getFilePickerInitialPath()) {
-            Thread {
+            ensureBackgroundThread {
                 lastFilePickerPath = it
                 if (it.isAudioFast()) {
                     RoomHelper(applicationContext).addSongToPlaylist(it)
@@ -431,15 +428,15 @@ class MainActivity : SimpleActivity(), SongListListener {
                 } else {
                     toast(R.string.invalid_file_format)
                 }
-            }.start()
+            }
         }
     }
 
     private fun createPlaylistFromFolder() {
         FilePickerDialog(this, getFilePickerInitialPath(), pickFile = false) {
-            Thread {
+            ensureBackgroundThread {
                 createPlaylistFrom(it)
-            }.start()
+            }
         }
     }
 

app/src/main/kotlin/com/simplemobiletools/musicplayer/activities/PlaylistsActivity.kt

@@ -3,6 +3,7 @@ package com.simplemobiletools.musicplayer.activities
 import android.os.Bundle
 import android.view.Menu
 import android.view.MenuItem
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.musicplayer.R
 import com.simplemobiletools.musicplayer.adapters.PlaylistsAdapter
 import com.simplemobiletools.musicplayer.dialogs.NewPlaylistDialog
@@ -20,7 +21,7 @@ class PlaylistsActivity : SimpleActivity(), RefreshPlaylistsListener {
     }
 
     private fun getPlaylists() {
-        Thread {
+        ensureBackgroundThread {
             val playlists = playlistDAO.getAll() as ArrayList<Playlist>
             runOnUiThread {
                 PlaylistsAdapter(this@PlaylistsActivity, playlists, this@PlaylistsActivity, playlists_list) {
@@ -30,7 +31,7 @@ class PlaylistsActivity : SimpleActivity(), RefreshPlaylistsListener {
                     playlists_list.adapter = this
                 }
             }
-        }.start()
+        }
     }
 
     override fun refreshItems() {

app/src/main/kotlin/com/simplemobiletools/musicplayer/adapters/PlaylistsAdapter.kt

@@ -5,6 +5,7 @@ import android.view.View
 import android.view.ViewGroup
 import com.simplemobiletools.commons.adapters.MyRecyclerViewAdapter
 import com.simplemobiletools.commons.extensions.*
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.commons.models.FileDirItem
 import com.simplemobiletools.commons.views.MyRecyclerView
 import com.simplemobiletools.musicplayer.R
@@ -115,7 +116,7 @@ class PlaylistsAdapter(activity: SimpleActivity, val playlists: ArrayList<Playli
 
         playlists.removeAll(playlistsToDelete)
 
-        Thread {
+        ensureBackgroundThread {
             val isDeletingCurrentPlaylist = ids.contains(activity.config.currentPlaylist)
             activity.deletePlaylists(playlistsToDelete)
             activity.runOnUiThread {
@@ -125,7 +126,7 @@ class PlaylistsAdapter(activity: SimpleActivity, val playlists: ArrayList<Playli
                     removeSelectedItems(positions)
                 }
             }
-        }.start()
+        }
     }
 
     private fun getItemWithKey(key: Int): Playlist? = playlists.firstOrNull { it.id == key }

app/src/main/kotlin/com/simplemobiletools/musicplayer/adapters/SongAdapter.kt

@@ -9,6 +9,7 @@ import com.simplemobiletools.commons.adapters.MyRecyclerViewAdapter
 import com.simplemobiletools.commons.dialogs.ConfirmationDialog
 import com.simplemobiletools.commons.dialogs.PropertiesDialog
 import com.simplemobiletools.commons.extensions.*
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.commons.models.FileDirItem
 import com.simplemobiletools.commons.views.FastScroller
 import com.simplemobiletools.commons.views.MyRecyclerView
@@ -186,12 +187,12 @@ class SongAdapter(activity: SimpleActivity, var songs: ArrayList<Song>, val list
 
     private fun askConfirmDelete() {
         ConfirmationDialog(activity) {
-            Thread {
+            ensureBackgroundThread {
                 deleteSongs()
                 activity.runOnUiThread {
                     finishActMode()
                 }
-            }.start()
+            }
         }
     }
 
@@ -284,13 +285,13 @@ class SongAdapter(activity: SimpleActivity, var songs: ArrayList<Song>, val list
         songs.removeAll(removeSongs)
         positions.sortDescending()
         removeSelectedItems(positions)
-        Thread {
+        ensureBackgroundThread {
             activity.songsDAO.removeSongsFromPlaylists(removeSongs)
 
             if (songs.isEmpty()) {
                 listener.refreshItems()
             }
-        }.start()
+        }
     }
 
     private fun getFirstSelectedItemPath() = getSelectedSongs().firstOrNull()?.path ?: ""
@@ -357,10 +358,10 @@ class SongAdapter(activity: SimpleActivity, var songs: ArrayList<Song>, val list
             if (songs.isNotEmpty() && currentSong != null) {
                 selectedKeys.add(currentSong!!.path.hashCode())
                 activity.sendIntent(NEXT)
-                Thread {
+                ensureBackgroundThread {
                     deleteSongs()
                     selectedKeys.clear()
-                }.start()
+                }
             }
         }
     }

app/src/main/kotlin/com/simplemobiletools/musicplayer/dialogs/EditDialog.kt

@@ -6,6 +6,7 @@ import android.provider.MediaStore
 import androidx.appcompat.app.AlertDialog
 import com.simplemobiletools.commons.activities.BaseSimpleActivity
 import com.simplemobiletools.commons.extensions.*
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.musicplayer.R
 import com.simplemobiletools.musicplayer.extensions.songsDAO
 import com.simplemobiletools.musicplayer.models.Song
@@ -69,13 +70,13 @@ class EditDialog(val activity: BaseSimpleActivity, val song: Song, val callback:
     }
 
     private fun storeEditedSong(song: Song, oldPath: String, newPath: String) {
-        Thread {
+        ensureBackgroundThread {
             try {
                 activity.songsDAO.updateSongInfo(newPath, song.artist, song.title, oldPath)
             } catch (e: Exception) {
                 activity.showErrorToast(e)
             }
-        }.start()
+        }
     }
 
     private fun updateContentResolver(context: Context, songID: Long, newSongTitle: String, newSongArtist: String) {

app/src/main/kotlin/com/simplemobiletools/musicplayer/dialogs/NewPlaylistDialog.kt

@@ -6,6 +6,7 @@ import com.simplemobiletools.commons.extensions.setupDialogStuff
 import com.simplemobiletools.commons.extensions.showKeyboard
 import com.simplemobiletools.commons.extensions.toast
 import com.simplemobiletools.commons.extensions.value
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.musicplayer.R
 import com.simplemobiletools.musicplayer.extensions.getPlaylistIdWithTitle
 import com.simplemobiletools.musicplayer.extensions.playlistDAO
@@ -33,7 +34,7 @@ class NewPlaylistDialog(val activity: Activity, var playlist: Playlist? = null,
                         showKeyboard(view.new_playlist_title)
                         getButton(AlertDialog.BUTTON_POSITIVE).setOnClickListener {
                             val title = view.new_playlist_title.value
-                            Thread {
+                            ensureBackgroundThread {
                                 val playlistIdWithTitle = activity.getPlaylistIdWithTitle(title)
                                 var isPlaylistTitleTaken = isNewPlaylist && playlistIdWithTitle != -1
                                 if (!isPlaylistTitleTaken) {
@@ -42,10 +43,10 @@ class NewPlaylistDialog(val activity: Activity, var playlist: Playlist? = null,
 
                                 if (title.isEmpty()) {
                                     activity.toast(R.string.empty_name)
-                                    return@Thread
+                                    return@ensureBackgroundThread
                                 } else if (isPlaylistTitleTaken) {
                                     activity.toast(R.string.playlist_name_exists)
-                                    return@Thread
+                                    return@ensureBackgroundThread
                                 }
 
                                 playlist!!.title = title
@@ -63,7 +64,7 @@ class NewPlaylistDialog(val activity: Activity, var playlist: Playlist? = null,
                                 } else {
                                     activity.toast(R.string.unknown_error_occurred)
                                 }
-                            }.start()
+                            }
                         }
                     }
                 }

app/src/main/kotlin/com/simplemobiletools/musicplayer/services/MusicService.kt

@@ -31,6 +31,7 @@ import androidx.core.app.NotificationCompat
 import androidx.media.session.MediaButtonReceiver
 import com.simplemobiletools.commons.extensions.*
 import com.simplemobiletools.commons.helpers.PERMISSION_WRITE_STORAGE
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.commons.helpers.isOreoPlus
 import com.simplemobiletools.musicplayer.R
 import com.simplemobiletools.musicplayer.activities.MainActivity
@@ -182,12 +183,12 @@ class MusicService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
 
     private fun handleInit() {
         mIsThirdPartyIntent = false
-        Thread {
+        ensureBackgroundThread {
             if (!mIsServiceInitialized) {
                 initService()
             }
             initSongs()
-        }.start()
+        }
     }
 
     private fun handleInitPath(intent: Intent) {
@@ -245,7 +246,7 @@ class MusicService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
 
     private fun handleRefreshList(intent: Intent) {
         mSongs.clear()
-        Thread {
+        ensureBackgroundThread {
             getSortedSongs()
             Handler(Looper.getMainLooper()).post {
                 mBus!!.post(Events.PlaylistUpdated(mSongs))
@@ -255,7 +256,7 @@ class MusicService : Service(), MediaPlayer.OnPreparedListener, MediaPlayer.OnEr
                 mPlayOnPrepare = false
                 setupNextSong()
             }
-        }.start()
+        }
     }
 
     private fun handleSetProgress(intent: Intent) {