Ufdjrw

I'm trying to make an animation of sorting algorithms in flutter. So far I've coded the algorithm and managed to get some sort of animation by iterating once at a time instead of the whole sorting process but you have to keep tapping the button to sort, one item at a time. I've been trying to look for a way to animate this process. Here's my code:

import 'package:flutter/material.dart';
import 'dart:math';

List<double> rectHeights = new List<double>();
int n = 2;

void main() => runApp(MyApp());

class MyApp extends StatelessWidget 
 @override
 Widget build(BuildContext context) 
 return MaterialApp(
 title: 'Sorting',
 theme: ThemeData(
 primarySwatch: Colors.blue,
 ),
 home: MyHomePage(),
 );
 


class MyHomePage extends StatefulWidget 
 MyHomePage(Key key) : super(key: key);

 @override
 _MyHomePageState createState() => _MyHomePageState();


class _MyHomePageState extends State<MyHomePage> with SingleTickerProviderStateMixin 
 int _selectedIndex = 0;
 final _widgetOptions = [
 Text('Index 0: Sort'),
 Text('Index 1: Shuffle'),
 ];

 @override
 void initState() 
 super.initState();
 Random random = new Random();
 for (int i = 0; i < 35; i++) 
 double ranNum = random.nextDouble() * 600;
 rectHeights.add(ranNum);
 
 

 @override
 Widget build(BuildContext context) 
 return Scaffold(
 body: Padding(
 padding: EdgeInsets.all(8.0),
 child: Center(
 child: Row(
 children: rectangles(),
 ),
 ),
 ),
 bottomNavigationBar: BottomNavigationBar(
 iconSize: 50.0,
 items: <BottomNavigationBarItem>[
 BottomNavigationBarItem(icon: Icon(Icons.sort), title: Text('Sort', style: TextStyle(fontSize: 20.0),)),
 BottomNavigationBarItem(icon: Icon(Icons.shuffle), title: Text('Shuffle', style: TextStyle(fontSize: 20.0),)),
 ],
 currentIndex: _selectedIndex,
 fixedColor: Colors.blue,
 onTap: _onItemTapped,
 ),
 );
 

 void _onItemTapped(int index) 
 setState(() 
 _selectedIndex = index;
 );
 switch(_selectedIndex) 
 case 0:
 setState(() 
 insertSortOnce(rectHeights, 1);
 );
 break;
 case 1:
 setState(() 
 shuffle(rectHeights);
 n = 2;
 );

 
 



List<Widget> rectangles() 
 List<Widget> rects = new List<Widget>();
 for (double height in rectHeights) 
 var rect = Padding(
 padding: EdgeInsets.symmetric(horizontal: 1.0),
 child: Container(
 width: 8.0,
 height: height,
 decoration: BoxDecoration(
 shape: BoxShape.rectangle,
 color: Colors.blue
 ),
 ),
 );
 rects.add(rect);
 
 return rects;


void insertSort(values, choice) 
 int i, j;
 double key, temp;
 for (i = 1; i < values.length; i++) 
 key = values[i];
 j = i - 1;
 switch (choice) 
 case 1:
 while (j >= 0 && key < values[j]) 
 temp = values[j];
 values[j] = values[j + 1];
 values[j + 1] = temp;
 j--;
 
 break;
 case 2:
 while (j >= 0 && key > values[j]) 
 temp = values[j];
 values[j] = values[j + 1];
 values[j + 1] = temp;
 j--;
 
 break;
 
 


void insertSortOnce(values, choice) 
 int i, j;
 double key, temp;
 for (i = 1; i < n; i++) 
 key = values[i];
 j = i - 1;
 switch (choice) 
 case 1:
 while (j >= 0 && key < values[j]) 
 temp = values[j];
 values[j] = values[j + 1];
 values[j + 1] = temp;
 j--;
 
 break;
 case 2:
 while (j >= 0 && key > values[j]) 
 temp = values[j];
 values[j] = values[j + 1];
 values[j + 1] = temp;
 j--;
 
 break;
 
 
 n++;


List shuffle(List items) 
 var random = new Random();

 // Go through all elements.
 for (var i = items.length - 1; i > 0; i--) 

 // Pick a pseudorandom number according to the list length
 var n = random.nextInt(i + 1);

 var temp = items[i];
 items[i] = items[n];
 items[n] = temp;
 

 return items;

You can use a Future function with a short delay, for example (one second) to call the insertSort() after each second till the rectHeights are sorted:

 var _notSorted = true ;
 var _shiftNotPressed = true ;

 Future sortRectangles() async 
 while(_notSorted & _shiftPressed) // You have to provide a condition to know when to stop
 await new Future.delayed(const Duration(seconds: 1), () 
 insertSortOnce(rectHeights, 1);
 
 );
 
 

Then checking for shuffling:

 void _onItemTapped(int index) 
setState(() 
 _selectedIndex = index;
);
switch(_selectedIndex) 
 case 0:
 setState(() 
 insertSortOnce(rectHeights, 1);
 );
 break;
 case 1:
 _shiftNotPressed = false ; // This is what you should add
 setState(() 
 shuffle(rectHeights);
 n = 2;
 );

 

Then Sorting completion:

 void insertSortOnce(values, choice) 
 _notSorted = false ; // if it didn't execute the loop it means sorted 
 int i, j;
 double key, temp;
 for (i = 1; i < n; i++) 
 key = values[i];
 j = i - 1;
 switch (choice) 
 case 1:
 while (j >= 0 && key < values[j]) 
 _notSorted = true ; //You should figure a more efficient way to do this
 temp = values[j];
 values[j] = values[j + 1];
 values[j + 1] = temp;
 j--;
 
 break;
 case 2:
 while (j >= 0 && key > values[j]) 
 temp = values[j];
 values[j] = values[j + 1];
 values[j + 1] = temp;
 j--;
 
 break;
 
 
 n++;

Also, You should include in your condition whether the shift button is pressed and to terminate accordingly.