アプリ固有のファイルにアクセスする

val file = File(context.filesDir, filename)

File file = new File(context.getFilesDir(), filename);

val filename = "myfile" val fileContents = "Hello world!" context.openFileOutput(filename, Context.MODE_PRIVATE).use {         it.write(fileContents.toByteArray()) }

String filename = "myfile"; String fileContents = "Hello world!"; try (FileOutputStream fos = context.openFileOutput(filename, Context.MODE_PRIVATE)) {     fos.write(fileContents.toByteArray()); }

context.openFileInput(filename).bufferedReader().useLines { lines ->     lines.fold("") { some, text ->         "$some\n$text"     } }

FileInputStream fis = context.openFileInput(filename); InputStreamReader inputStreamReader =         new InputStreamReader(fis, StandardCharsets.UTF_8); StringBuilder stringBuilder = new StringBuilder(); try (BufferedReader reader = new BufferedReader(inputStreamReader)) {     String line = reader.readLine();     while (line != null) {         stringBuilder.append(line).append('\n');         line = reader.readLine();     } } catch (IOException e) {     // Error occurred when opening raw file for reading. } finally {     String contents = stringBuilder.toString(); }

var files: Array<String> = context.fileList()

Array<String> files = context.fileList();

context.getDir(dirName, Context.MODE_PRIVATE)

File directory = context.getFilesDir(); File file = new File(directory, filename);

File.createTempFile(filename, null, context.cacheDir)

File.createTempFile(filename, null, context.getCacheDir());

val cacheFile = File(context.cacheDir, filename)

File cacheFile = new File(context.getCacheDir(), filename);

// Checks if a volume containing external storage is available // for read and write. fun isExternalStorageWritable(): Boolean {     return Environment.getExternalStorageState() == Environment.MEDIA_MOUNTED }  // Checks if a volume containing external storage is available to at least read. fun isExternalStorageReadable(): Boolean {      return Environment.getExternalStorageState() in         setOf(Environment.MEDIA_MOUNTED, Environment.MEDIA_MOUNTED_READ_ONLY) }

// Checks if a volume containing external storage is available // for read and write. private boolean isExternalStorageWritable() {     return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED); }  // Checks if a volume containing external storage is available to at least read. private boolean isExternalStorageReadable() {      return Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED) ||             Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED_READ_ONLY); }

val externalStorageVolumes: Array<out File> =         ContextCompat.getExternalFilesDirs(applicationContext, null) val primaryExternalStorage = externalStorageVolumes[0]

File[] externalStorageVolumes =         ContextCompat.getExternalFilesDirs(getApplicationContext(), null); File primaryExternalStorage = externalStorageVolumes[0];

val appSpecificExternalDir = File(context.getExternalFilesDir(null), filename)

File appSpecificExternalDir = new File(context.getExternalFilesDir(null), filename);

val externalCacheFile = File(context.externalCacheDir, filename)

File externalCacheFile = new File(context.getExternalCacheDir(), filename);

externalCacheFile.delete()

externalCacheFile.delete();

fun getAppSpecificAlbumStorageDir(context: Context, albumName: String): File? {     // Get the pictures directory that's inside the app-specific directory on     // external storage.     val file = File(context.getExternalFilesDir(             Environment.DIRECTORY_PICTURES), albumName)     if (!file?.mkdirs()) {         Log.e(LOG_TAG, "Directory not created")     }     return file }

@Nullable File getAppSpecificAlbumStorageDir(Context context, String albumName) {     // Get the pictures directory that's inside the app-specific directory on     // external storage.     File file = new File(context.getExternalFilesDir(             Environment.DIRECTORY_PICTURES), albumName);     if (file == null || !file.mkdirs()) {         Log.e(LOG_TAG, "Directory not created");     }     return file; }

// App needs 10 MB within internal storage. const val NUM_BYTES_NEEDED_FOR_MY_APP = 1024 * 1024 * 10L;  val storageManager = applicationContext.getSystemService<StorageManager>()!! val appSpecificInternalDirUuid: UUID = storageManager.getUuidForPath(filesDir) val availableBytes: Long =         storageManager.getAllocatableBytes(appSpecificInternalDirUuid) if (availableBytes >= NUM_BYTES_NEEDED_FOR_MY_APP) {     storageManager.allocateBytes(         appSpecificInternalDirUuid, NUM_BYTES_NEEDED_FOR_MY_APP) } else {     val storageIntent = Intent().apply {         // To request that the user remove all app cache files instead, set         // "action" to ACTION_CLEAR_APP_CACHE.         action = ACTION_MANAGE_STORAGE     } }

// App needs 10 MB within internal storage. private static final long NUM_BYTES_NEEDED_FOR_MY_APP = 1024 * 1024 * 10L;  StorageManager storageManager =         getApplicationContext().getSystemService(StorageManager.class); UUID appSpecificInternalDirUuid = storageManager.getUuidForPath(getFilesDir()); long availableBytes =         storageManager.getAllocatableBytes(appSpecificInternalDirUuid); if (availableBytes >= NUM_BYTES_NEEDED_FOR_MY_APP) {     storageManager.allocateBytes(             appSpecificInternalDirUuid, NUM_BYTES_NEEDED_FOR_MY_APP); } else {     // To request that the user remove all app cache files instead, set     // "action" to ACTION_CLEAR_APP_CACHE.     Intent storageIntent = new Intent();     storageIntent.setAction(ACTION_MANAGE_STORAGE); }