Restore accidental deletions from Android plugin

Author: amake

android/src/main/kotlin/codeux/design/filepicker/file_picker_writable/FilePickerWritablePlugin.kt

@@ -89,11 +89,44 @@ class FilePickerWritablePlugin : FlutterPlugin, MethodCallHandler,
               ?: throw FilePickerException("Expected argument 'path'")
             impl.openFilePickerForCreate(result, path)
           }
+          "isDirectoryAccessSupported" -> {
+            result.success(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
+          }
+          "openDirectoryPicker" -> {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+              val initialDirUri = call.argument<String>("initialDirUri")
+              impl.openDirectoryPicker(result, initialDirUri)
+            } else {
+              throw FilePickerException("${call.method} is not supported on Android ${Build.VERSION.RELEASE}")
+            }
+          }
           "readFileWithIdentifier" -> {
             val identifier = call.argument<String>("identifier")
               ?: throw FilePickerException("Expected argument 'identifier'")
             impl.readFileWithIdentifier(result, identifier)
           }
+          "getDirectory" -> {
+            val rootIdentifier = call.argument<String>("rootIdentifier")
+              ?: throw FilePickerException("Expected argument 'rootIdentifier'")
+            val fileIdentifier = call.argument<String>("fileIdentifier")
+              ?: throw FilePickerException("Expected argument 'fileIdentifier'")
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+              impl.getDirectory(result, rootIdentifier, fileIdentifier)
+            } else {
+              throw FilePickerException("${call.method} is not supported on Android ${Build.VERSION.RELEASE}")
+            }
+          }
+          "resolveRelativePath" -> {
+            val directoryIdentifier = call.argument<String>("directoryIdentifier")
+              ?: throw FilePickerException("Expected argument 'directoryIdentifier'")
+            val relativePath = call.argument<String>("relativePath")
+              ?: throw FilePickerException("Expected argument 'relativePath'")
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+              impl.resolveRelativePath(result, directoryIdentifier, relativePath)
+            } else {
+              throw FilePickerException("${call.method} is not supported on Android ${Build.VERSION.RELEASE}")
+            }
+          }
           "writeFileWithIdentifier" -> {
             val identifier = call.argument<String>("identifier")
               ?: throw FilePickerException("Expected argument 'identifier'")