add cleanCache api

android/src/main/kotlin/com/morbit/photogallery/PhotoGalleryPlugin.kt

@@ -10,6 +10,7 @@ import io.flutter.plugin.common.MethodChannel.Result
 import io.flutter.plugin.common.PluginRegistry.Registrar
 import android.graphics.Bitmap
 import java.io.ByteArrayOutputStream
+import java.io.File
 import android.provider.MediaStore
 import android.content.Context
 import android.database.Cursor
@@ -140,6 +141,10 @@ class PhotoGalleryPlugin : FlutterPlugin, MethodCallHandler {
                     result.success(v)
                 })
             }
+            "cleanCache" -> {
+                cleanCache()
+                result.success(null)
+            }
             else -> result.notImplemented()
         }
     }
@@ -638,6 +643,21 @@ class PhotoGalleryPlugin : FlutterPlugin, MethodCallHandler {
             "modifiedDate" to dateModified
         )
     }
+
+    private fun getCachePath(): File? {
+        return this.context?.run {
+            val cachePath = File(this.cacheDir, "photo_gallery")
+            if (!cachePath.exists()) {
+                cachePath.mkdirs()
+            }
+            return@run cachePath
+        }
+    }
+
+    private fun cleanCache() {
+        val cachePath = getCachePath()
+        cachePath?.deleteRecursively()
+    }
 }
 
 class BackgroundAsyncTask<T>(val handler: () -> T, val post: (result: T) -> Unit) : AsyncTask<Void, Void, T>() {

ios/Classes/SwiftPhotoGalleryPlugin.swift

@@ -75,6 +75,10 @@ public class SwiftPhotoGalleryPlugin: NSObject, FlutterPlugin {
           result(filepath?.replacingOccurrences(of: "file://", with: ""))
       })
     }
+    else if(call.method == "cleanCache") {
+      cleanCache()
+      result(nil)
+    }
     else {
       result(FlutterMethodNotImplemented)
     }
@@ -387,11 +391,8 @@ public class SwiftPhotoGalleryPlugin: NSObject, FlutterPlugin {
     let mediumId = asset.localIdentifier
       .replacingOccurrences(of: "/", with: "__")
       .replacingOccurrences(of: "\\", with: "__")
-    let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
+    let cachePath = self.cachePath()
-    let tempFolder = paths[0].appendingPathComponent("photo_gallery")
+    return cachePath.appendingPathComponent(mediumId + ext)
-    try! FileManager.default.createDirectory(at: tempFolder, withIntermediateDirectories: true, attributes: nil)
-    
-    return tempFolder.appendingPathComponent(mediumId+ext)
   }
   
   private func toSwiftMediumType(value: String) -> PHAssetMediaType? {
@@ -448,4 +449,15 @@ public class SwiftPhotoGalleryPlugin: NSObject, FlutterPlugin {
     let uti = self.extractUTIFromAsset(asset: asset)
     return self.extractFileExtensionFromUTI(uti: uti)
   }
+  
+  private func cachePath() -> URL {
+    let paths = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)
+    let cacheFolder = paths[0].appendingPathComponent("photo_gallery")
+    try! FileManager.default.createDirectory(at: cacheFolder, withIntermediateDirectories: true, attributes: nil)
+    return cacheFolder
+  }
+  
+  private func cleanCache() {
+    try? FileManager.default.removeItem(at: self.cachePath())
+  }
 }

lib/photo_gallery.dart

@@ -113,4 +113,8 @@ class PhotoGallery {
     }) as String;
     return File(path);
   }
+
+  static Future<void> cleanCache() async {
+    _channel.invokeMethod('cleanCache', {});
+  }
 }