Merge pull request #171 from tkskto/fix/viewshot-01

add null check

android/src/main/java/fr/greweb/reactnativeviewshot/ViewShot.java

@@ -184,18 +184,20 @@ public class ViewShot implements UIBlock {
             if(child instanceof TextureView) {
                 ((TextureView) child).setOpaque(false);
                 childBitmapBuffer = ((TextureView) child).getBitmap(child.getWidth(), child.getHeight());
-                int left = child.getLeft();
-                int top = child.getTop();
-                View parentElem = (View)child.getParent();
-                while (parentElem != null) {
-                    if (parentElem == view) {
-                        break;
+                if (childBitmapBuffer != null) {
+                    int left = child.getLeft();
+                    int top = child.getTop();
+                    View parentElem = (View)child.getParent();
+                    while (parentElem != null) {
+                        if (parentElem == view) {
+                            break;
+                        }
+                        left += parentElem.getLeft();
+                        top += parentElem.getTop();
+                        parentElem = (View)parentElem.getParent();
                     }
-                    left += parentElem.getLeft();
-                    top += parentElem.getTop();
-                    parentElem = (View)parentElem.getParent();
+                    c.drawBitmap(childBitmapBuffer, left + child.getPaddingLeft(), top + child.getPaddingTop(), null);
                 }
-                c.drawBitmap(childBitmapBuffer, left + child.getPaddingLeft(),  top + child.getPaddingTop(), null);
             }
         }