complete when getting a null frame instance

Author: JBerendes

android/src/main/java/com/shahenlibrary/Trimmer/Trimmer.java

@@ -93,6 +93,9 @@ public static void getPreviewImages(String path, Promise promise, ReactApplicati
 
     for (int i = 0; i < duration; i += duration / 10) {
       Bitmap frame = retriever.getFrameAtTime(i * 1000);
+      if(frame == null) {
+        continue;
+      }
       Bitmap currBmp = Bitmap.createScaledBitmap(frame, resizeWidth, resizeHeight, false);
 
       Bitmap normalizedBmp = Bitmap.createBitmap(currBmp, 0, 0, resizeWidth, resizeHeight, mx, true);