Fix leaking tickers

Author: thecodepapaya

lib/src/widgets/flow_shader.dart

@@ -26,6 +26,12 @@ class _FlowShaderState extends State<FlowShader>
   late Animation animation2;
   late Animation animation3;
 
+  @override
+  void dispose() {
+    controller.dispose();
+    super.dispose();
+  }
+
   @override
   void initState() {
     super.initState();

lib/src/widgets/record_button.dart

@@ -77,6 +77,7 @@ class _RecordButtonState extends State<RecordButton> {
   void dispose() {
     record.dispose();
     timer?.cancel();
+    timer = null;
     super.dispose();
   }
 
@@ -171,16 +172,17 @@ class _RecordButtonState extends State<RecordButton> {
             behavior: HitTestBehavior.opaque,
             onTap: () async {
               var filePath = await Record().stop();
+              timer?.cancel();
+              timer = null;
+              startTime = null;
+              recordDuration = "00:00";
               AudioState.files.add(filePath!);
               Globals.audioListKey.currentState!
                   .insertItem(AudioState.files.length - 1);
               debugPrint(filePath);
               setState(() {
                 isLocked = false;
               });
-              startTime = null;
-              recordDuration = "00:00";
-              timer?.cancel();
             },
             child: Row(
               mainAxisAlignment: MainAxisAlignment.spaceBetween,
@@ -231,9 +233,11 @@ class _RecordButtonState extends State<RecordButton> {
         widget.controller.reverse();
 
         if (isCancelled(details.localPosition)) {
+          timer?.cancel();
+          timer = null;
           startTime = null;
           recordDuration = "00:00";
-          timer?.cancel();
+
           debugPrint("Cancelled recording");
           var filePath = await record.stop();
           debugPrint(filePath);
@@ -245,9 +249,11 @@ class _RecordButtonState extends State<RecordButton> {
             isLocked = true;
           });
         } else {
+          timer?.cancel();
+          timer = null;
           startTime = null;
           recordDuration = "00:00";
-          timer?.cancel();
+
           var filePath = await Record().stop();
           AudioState.files.add(filePath!);
           Globals.audioListKey.currentState!