title: Flutter automaticallyImplyLeading not working
body: <p>I want to remove the back button from the new page in navigator, to have my own custon button for doing that. However, even after setting automaticallyImplyLeading to false, I am getting the back button. How can I fix this? If the user presses the back button on their device, will the page still go back to the earlier one? If so, how to fic that? This is my code : -</p>
  <pre><code>
  import 'package:flutter/material.dart';
  
  class toDoList extends StatefulWidget
  {
      bool data = false;
      @override
      createState() 
      {
          return new toDoListState();
      }
  }
  
  class toDoListState extends State&lt;toDoList&gt;
  {
    List&lt;String&gt; tasks = [];
    List&lt;String&gt; completedTasks = [];
    List&lt;String&gt; descriptions = [];
    List&lt;bool&gt; importance = [];
    List&lt;String&gt; time2completion = [];var _chosenValue;
    
      @override
      Widget build(BuildContext context)
      {
          return Scaffold
          (
              body: buildToDoList(),
              floatingActionButton: new FloatingActionButton
              (
                  onPressed: addToDoItemScreen, 
                  tooltip: 'Add Task',
                  child: new Icon(Icons.add),
              ),
          );
      }
  
      Widget buildToDoList()
      {
          return new ListView.builder
          (
              itemBuilder: (context, index)
              {
                  if(index &lt; tasks.length)
                  {
                      return row(tasks[index], descriptions[index], index);
                  }
              },
          );
      }
  
      Widget row(String task, String description, int index)
      {                  
          return Dismissible(
          key: UniqueKey(),
          background: Container(color: Colors.red, child: Align(alignment: Alignment.center, child: Text('DELETE', textAlign: TextAlign.center, style: TextStyle(color: Colors.white, fontSize: 18),))),
          direction: DismissDirection.horizontal,
          onDismissed: (direction) {
          setState(() {
            tasks.removeAt(index);
            if(completedTasks.contains(task))
            {
                completedTasks.removeAt(index);
            }
            descriptions.removeAt(index);
            importance.removeAt(index);
          });
            Scaffold.of(context).showSnackBar(SnackBar(content: Text(task+&quot; dismissed&quot;)));
          },
          child: CheckboxListTile(
            controlAffinity: ListTileControlAffinity.leading,
            title: Text(task, style: (completedTasks.contains(task)) ? TextStyle(decoration: TextDecoration.lineThrough) : TextStyle(),),
            subtitle: Text(descriptions[index]),
            value: completedTasks.contains(task),
            onChanged: (bool value) {
             setState(() {
                if(!completedTasks.contains(task))
                {
                    completedTasks.add(task);
                }
                else
                {
                    completedTasks.remove(task);
                }
             });
            },
          ));
      }
    
    void addToDoItemScreen() {
      int index = tasks.length;
      while (importance.length &gt; tasks.length) {
        importance.removeLast();
      }
      importance.add(false);
      
      Navigator.of(context).push(new MaterialPageRoute(builder: (context) {
        return StatefulBuilder(builder: (context, setState) { // this is new
                  return new Scaffold(
                      appBar: new AppBar(automaticallyImplyLeading: false, title: new Text('Add a new task')),
                      body: Form(
                        child: Column(
                          children: &lt;Widget&gt;[
                            TextField(
                              autofocus: true,
                              onSubmitted: (name) {
                                addToDoItem(name);
                                //Navigator.pop(context); // Close the add todo screen
                              },
                              decoration: new InputDecoration(
                                  hintText: 'Enter something to do...',
                                  contentPadding: const EdgeInsets.all(20.0),
                                  border: OutlineInputBorder()),
                            ),
                            TextField(
                              //autofocus: true,
                              //enabled: descriptions.length &gt; desc,
                              onSubmitted: (val) {
                                addDescription(val, index);
                              },
                              decoration: new InputDecoration(
                                  hintText: 'Enter a task decription...',
                                  contentPadding: const EdgeInsets.all(20.0),
                                  border: OutlineInputBorder()),
                            ),
                            Row(
                              children: &lt;Widget&gt; [
                                Switch(
                                value: importance[index],
                                onChanged: (val) {
                                  setState(() {
                                  });
                                  impTask(index);
                                },
                              ),
                              Text('Important Task', style: TextStyle(fontSize: 18)),
                              ],
                            ),
                            DropdownButton&lt;String&gt; 
                            (
                                value: _chosenValue,
                                items: &lt;String&gt;['none', '30 minute', '1 hour', '12 hours', '1 day', 'custom'].map&lt;DropdownMenuItem&lt;String&gt;&gt;((String value) {
                                    return DropdownMenuItem&lt;String&gt;(
                                    value: value,
                                    child: Text(value),
                            );
                              }).toList(),
                          onChanged: (String value) {
                            setState(() {
                              _chosenValue = value;
                          });
                        }),
                    RaisedButton(onPressed: () =&gt; Navigator.pop(context), child: Text('DONE', style: TextStyle(fontSize: 20)),)
                  ],
                ),
              ));
        });
      }));
    }
  
      void addToDoItem(String task)
      {
          setState(() {
            tasks.add(task);
            descriptions.add(&quot;No description&quot;);
          });
      }
  
      void addDescription(String desc, int index)
      {
          setState(() {
            descriptions[index] = desc;
          });
      }
  
      void impTask(int index)
      {
          setState(() {
            if(importance[index])
            {
              importance[index] = false;
            }
            else 
            {
              importance[index] = true;
            }
          });
      }
  }
  </code></pre>