formating and fixing warnings

lib/animation.dart

@@ -61,8 +61,8 @@ class Animation {
     int amount, {
     double textureX = 0.0,
     double textureY = 0.0,
-    double textureWidth = null,
-    double textureHeight = null,
+    double textureWidth,
+    double textureHeight,
     double stepTime = 0.1,
   }) {
     this.frames = new List<Frame>(amount);
@@ -85,8 +85,8 @@ class Animation {
     List<double> stepTimes, {
     double textureX = 0.0,
     double textureY = 0.0,
-    double textureWidth = null,
-    double textureHeight = null,
+    double textureWidth,
+    double textureHeight,
   }) {
     this.frames = new List<Frame>(amount);
     for (var i = 0; i < amount; i++) {
@@ -108,7 +108,7 @@ class Animation {
   bool get isLastFrame => currentIndex == frames.length - 1;
 
   /// Sets a different step time to each frame. The sizes of the arrays must match.
-  void set variableStepTimes(List<double> stepTimes) {
+  set variableStepTimes(List<double> stepTimes) {
     assert(stepTimes.length == frames.length);
     for (int i = 0; i < frames.length; i++) {
       frames[i].stepTime = stepTimes[i];

lib/components/text_box_component.dart

@@ -1,7 +1,7 @@
 import 'dart:ui';
 import 'dart:math' as math;
 
-import 'package:flutter/src/painting/text_painter.dart';
+import 'package:flutter/widgets.dart';
 
 import 'component.dart';
 import 'resizable.dart';

lib/components/tiled_component.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:ui';
 
 import 'package:flame/components/component.dart';
@@ -77,7 +78,5 @@ class TiledComponent extends Component {
   }
 
   @override
-  void update(double t) {
-    // TODO: implement update
-  }
+  void update(double t) {}
 }

lib/util.dart

@@ -57,7 +57,8 @@ class Util {
   /// Use this in order to get it to work in case your app also contains other widgets.
   void addGestureRecognizer(GestureRecognizer recognizer) {
     if (GestureBinding.instance == null) {
-      throw new Exception("GestureBinding is not initialized yet, this probably happened because addGestureRecognizer was called before the runApp method");
+      throw new Exception(
+          "GestureBinding is not initialized yet, this probably happened because addGestureRecognizer was called before the runApp method");
     }
 
     GestureBinding.instance.pointerRouter.addGlobalRoute((PointerEvent e) {

test/components/tiled_test.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:io';
 import 'dart:typed_data';