few changes

README.md

@@ -1,10 +1,36 @@
 # thumbnails
 
-A Flutter Plugin to generate thumbnails from videos on Android devices
+A Flutter Plugin to generate thumbnails from videos.
 
-## Getting Started
+## Compatibility
+Android OS only
 
-For help getting started with Flutter, view our online
-[documentation](https://flutter.io/).
+## Usage
 
-For help on editing plugin code, view the [documentation](https://flutter.io/developing-packages/#edit-plugin-package).
+#### Depend on it
+add `thumbnails` as a dependency in your pubspec.yaml file.
+
+#### Add import statement
+Import the library via
+``` dart
+import 'package:thumbnails/thumbnails.dart';
+```
+
+#### Examples
+``` dart
+    // Fetch thumbnail, store in a specified output folder and return file path
+    String thumb = await Thumbnails.getThumbnail(
+        thumbOutputFile:
+            '[YOUR OUTPUT FILE HERE]',
+        videoFile: '[VIDEO PATH HERE]',
+        imageType: ThumbFormat.PNG,
+        quality: 30);
+
+
+// Fetch thumbnail, store in app's Temporary directory output folder and return file path
+    String thumb = await Thumbnails.getThumbnail(
+        videoFile: 'VIDEO PATH HERE',
+        imageType: ThumbFormat.JPEG,
+        quality: 45);
+
+```

android/src/main/java/com/asapjay/thumbnails/ThumbnailsPlugin.java

@@ -2,6 +2,7 @@
 
 import android.graphics.Bitmap;
 import android.media.ThumbnailUtils;
+import android.net.Uri;
 import android.provider.MediaStore;
 import android.util.Log;
 
@@ -23,9 +24,15 @@ public class ThumbnailsPlugin implements MethodCallHandler {
     /**
      * Plugin registration.
      */
+    private Registrar mRegistrar;
+
+    private ThumbnailsPlugin(Registrar mRegistrar) {
+        this.mRegistrar = mRegistrar;
+    }
+
     public static void registerWith(Registrar registrar) {
         final MethodChannel channel = new MethodChannel(registrar.messenger(), "thumbnails");
-        channel.setMethodCallHandler(new ThumbnailsPlugin());
+        channel.setMethodCallHandler(new ThumbnailsPlugin(registrar));
     }
 
     @Override
@@ -38,8 +45,8 @@ public void onMethodCall(MethodCall call, Result result) {
             int imageType = (int) arguments.get("thumbnailFormat");
             int quality = (int) arguments.get("thumbnailQuality");
             try {
-                buildThumbnail(videoFile, thumbOutputFile, imageType, quality);
-                result.success("success");
+                String thumbnailPath = buildThumbnail(videoFile, thumbOutputFile, imageType, quality);
+                result.success(thumbnailPath);
             } catch (Throwable throwable) {
                 throwable.printStackTrace();
             }
@@ -48,51 +55,113 @@ public void onMethodCall(MethodCall call, Result result) {
         }
     }
 
-    private void buildThumbnail(String vidPath, String thumbPath, int type, int quality) {
+    private String buildThumbnail(String vidPath, String thumbPath, int type, int quality) {
+        if (vidPath == null || vidPath.equals("")) {
+            Log.println(Log.INFO, "WARNING", "Thumbnails: Video Path must not be null or empty!");
+            return null;
+        }
+        return thumbPath == null ? cacheDirectory(vidPath, type, quality) : userDirectory(vidPath, thumbPath, type, quality);
+
+    }
+
+    private String cacheDirectory(String vidPath, int type, int quality) {
+        Bitmap bitmap = ThumbnailUtils.createVideoThumbnail(vidPath, MediaStore.Video.Thumbnails.MINI_KIND);
+        String sourceFileName = Uri.parse(vidPath).getLastPathSegment();
+        String thumbDirPath = mRegistrar.context().getExternalCacheDir() + File.separator + "ThumbFiles" + File.separator;
+        String tempFile = thumbDirPath + sourceFileName;
+        File tempDir = new File(thumbDirPath);
 
-        if (vidPath == null || vidPath == "") {
-            Log.println(Log.INFO, "WARNING", "Thumbnails: Video Path must not be null or empty");
-            return;
+        if (tempDir.exists()) {
+            clearThumbnails();
+        } else {
+            tempDir.mkdirs();
         }
-        if (thumbPath == null || thumbPath == "") {
-            Log.println(Log.INFO, "WARNING", "Thumbnails: Thumbnail Path must not be null or empty");
-            return;
+
+        switch (type) {
+            case 1:
+                try {
+                    FileOutputStream out = new FileOutputStream(new File(tempFile + ".jpg"));
+                    bitmap.compress(Bitmap.CompressFormat.JPEG, quality, out);
+                    out.flush();
+                    out.close();
+                    return tempFile + ".jpg";
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            case 2:
+                try {
+                    FileOutputStream out = new FileOutputStream(new File(tempFile + ".png"));
+                    bitmap.compress(Bitmap.CompressFormat.PNG, quality, out);
+                    out.flush();
+                    out.close();
+                    return tempFile + ".png";
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            case 3:
+                try {
+                    FileOutputStream out = new FileOutputStream(new File(tempFile + ".webp"));
+                    bitmap.compress(Bitmap.CompressFormat.WEBP, quality, out);
+                    out.flush();
+                    out.close();
+                    return tempFile + ".webp";
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
         }
+        return "";
+    }
 
+    private String userDirectory(String vidPath, String thumbPath, int type, int quality) {
         Bitmap bitmap = ThumbnailUtils.createVideoThumbnail(vidPath, MediaStore.Video.Thumbnails.MINI_KIND);
         switch (type) {
             case 1:
                 try {
-                    FileOutputStream out = new FileOutputStream(new File(thumbPath));
+                    FileOutputStream out = new FileOutputStream(new File(thumbPath + ".jpg"));
                     bitmap.compress(Bitmap.CompressFormat.JPEG, quality, out);
                     out.flush();
                     out.close();
+                    return thumbPath + ".jpg";
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
                 break;
 
             case 2:
                 try {
-                    FileOutputStream out = new FileOutputStream(new File(thumbPath));
+                    FileOutputStream out = new FileOutputStream(new File(thumbPath + ".png"));
                     bitmap.compress(Bitmap.CompressFormat.PNG, quality, out);
                     out.flush();
                     out.close();
+                    return thumbPath + ".png";
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
                 break;
             case 3:
                 try {
-                    FileOutputStream out = new FileOutputStream(new File(thumbPath));
+                    FileOutputStream out = new FileOutputStream(new File(thumbPath + "webp"));
                     bitmap.compress(Bitmap.CompressFormat.WEBP, quality, out);
                     out.flush();
                     out.close();
+                    return thumbPath + ".webp";
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
                 break;
+        }
+        return "";
+    }
 
+    private void clearThumbnails() {
+        String tempDirPath = mRegistrar.context().getExternalCacheDir()
+                + File.separator + "TempFiles" + File.separator;
+        File tempDir = new File(tempDirPath);
+        if (tempDir.exists()) {
+            String[] children = tempDir.list();
+            for (String file : children) {
+                new File(tempDir, file).delete();
+            }
         }
     }
 }

example/lib/main.dart

@@ -1,7 +1,4 @@
 import 'package:flutter/material.dart';
-import 'dart:async';
-
-import 'package:flutter/services.dart';
 import 'package:thumbnails/thumbnails.dart';
 
 void main() => runApp(new MyApp());
@@ -12,33 +9,24 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> {
-
-  @override
-  void initState() {
-    super.initState();
-   // initPlatformState();
-  }
-
-  // Platform messages are asynchronous, so we initialize in an async method.
-  Future<void> initPlatformState() async {
-    String platformVersion;
-    // Platform messages may fail, so we use a try/catch PlatformException.
-    try {
-      await Thumbnails.getThumbnail(
-        thumbOutputFile: '/storage/emulated/0/Whatsapp/Media/Test${TimeOfDay.now()}.jpg',
+  // Fetch thumbnail and store in a specified output folder
+  void _buildThumbToFile() async {
+    String thumb = await Thumbnails.getThumbnail(
+        thumbOutputFile:
+            '/storage/emulated/0/Whatsapp/Media/Test${TimeOfDay.now()}.jpg',
         videoFile: '/storage/emulated/0/Whatsapp/Media/.Statuses/Testvid.mp4',
         imageType: ThumbFormat.PNG,
-        quality: 30
-      );
-    } on PlatformException {
-      platformVersion = 'Failed to get platform version.';
-    }
-
-    // If the widget was removed from the tree while the asynchronous platform
-    // message was in flight, we want to discard the reply rather than calling
-    // setState to update our non-existent appearance.
-    if (!mounted) return;
+        quality: 30);
+    print(thumb);
+  }
 
+// Fetch thumbnail and stores in app temporary directory (this is volatile)
+  void _buildThumbToCache() async {
+    String thumb = await Thumbnails.getThumbnail(
+        videoFile: '/storage/emulated/0/Whatsapp/Media/.Statuses/Testvid.mp4',
+        imageType: ThumbFormat.JPEG,
+        quality: 30);
+    print(thumb);
   }
 
   @override
@@ -49,9 +37,13 @@ class _MyAppState extends State<MyApp> {
           title: const Text('Plugin example app'),
         ),
         body: new Center(
-          child: FlatButton(
-            onPressed: ()=> initPlatformState(),
-            child: Text('Press Me'),
+          child: Column(
+            children: <Widget>[
+              RaisedButton(
+                  onPressed: _buildThumbToFile, child: Text('Build To File')),
+              RaisedButton(
+                  onPressed: _buildThumbToCache, child: Text('Build to Cache')),
+            ],
           ),
         ),
       ),

lib/thumbnails.dart

@@ -5,23 +5,13 @@ import 'package:flutter/services.dart';
 import 'package:thumbnails/validators.dart';
 
 enum ThumbFormat { PNG, JPEG, WEBP }
-class Thumbnails {
-  String videoFile;
-  String thumbOutputFile;
-  int imageType;
-  int quality;
-
-  Thumbnails(
-      {@required this.videoFile,
-      @required this.thumbOutputFile,
-      this.imageType,
-      this.quality});
 
+class Thumbnails {
   static const MethodChannel _channel = const MethodChannel('thumbnails');
 
- static Future<void> getThumbnail(
+  static Future<String> getThumbnail(
       {@required String videoFile,
-      @required String thumbOutputFile,
+      String thumbOutputFile,
       ThumbFormat imageType,
       int quality}) async {
     var utilMap = <String, dynamic>{
@@ -30,10 +20,7 @@ class Thumbnails {
       'thumbnailFormat': validateType(imageType),
       'thumbnailQuality': validateQuality(quality)
     };
-   await _channel.invokeMethod('getThumbnail', utilMap);
-   print('done!!');
+    String thumbnailPath = await _channel.invokeMethod('getThumbnail', utilMap);
+    return thumbnailPath;
   }
-
-
-
 }

lib/validators.dart

@@ -1,4 +1,3 @@
-
 import 'package:thumbnails/thumbnails.dart';
 
 const DEFAULT_THUMB_QUALITY = 50;