Fixed NPE if file failed to load.

spine-libgdx/spine-skeletonviewer/src/com/esotericsoftware/spine/SkeletonViewer.java

@@ -232,16 +232,18 @@ public class SkeletonViewer extends ApplicationAdapter {
 		ui.stage.draw();
 
 		// Draw indicator for timeline position.
-		ShapeRenderer shapes = debugRenderer.getShapeRenderer();
-		TrackEntry entry = state.getCurrent(0);
-		if (entry != null) {
-			float percent = entry.getTime() / entry.getEndTime();
-			if (entry.getLoop()) percent %= 1;
-			float x = ui.window.getRight() + (Gdx.graphics.getWidth() - ui.window.getRight()) * percent;
-			shapes.setColor(Color.CYAN);
-			shapes.begin(ShapeType.Line);
-			shapes.line(x, 0, x, 20);
-			shapes.end();
+		if (state != null) {
+			ShapeRenderer shapes = debugRenderer.getShapeRenderer();
+			TrackEntry entry = state.getCurrent(0);
+			if (entry != null) {
+				float percent = entry.getTime() / entry.getEndTime();
+				if (entry.getLoop()) percent %= 1;
+				float x = ui.window.getRight() + (Gdx.graphics.getWidth() - ui.window.getRight()) * percent;
+				shapes.setColor(Color.CYAN);
+				shapes.begin(ShapeType.Line);
+				shapes.line(x, 0, x, 20);
+				shapes.end();
+			}
 		}
 	}