Closing a Frame

BlitzMax Forums/Brucey's Modules/Closing a Frame

Glenn Dodd

(Posted 2008) [#1]

I want to close Frame2 when a button is clicked.
I thought frame2.show(False) would have been enough to bring Frame1 to the front again.
But i get an "Unhandled Exception: Attempt to access field or method of Null Object"

testFormOpening_Main.bmx

'
' Example application stub generated by wxCodeGen v1.06 : 05 Aug 2008 15:09:10
'
SuperStrict

Framework wx.wxApp

Import "testFormOpening_GUI.bmx"

New MyApp.run()

Type MyApp Extends wxApp

	Field frame:MyFrame1
	
	Method OnInit:Int()
?macos
		' make the default Mac font for controls not so big
		wxSystemOptions.SetOption(wxWINDOW_DEFAULT_VARIANT, wxWINDOW_VARIANT_SMALL)
?
		' create the frame
		Local frame:MyFrame1 = MyFrame1(New MyFrame1.Create(, , "Frame 1"))
		' frames are created hidden. You need to manually show it.
		frame.show()
		' make sure it is brought to the front
		SetTopWindow(frame)
		Return True
	End Method

End Type

Type MyFrame1 Extends MyFrame1Base

	Field frame2:MyFrame2

	Method OnInit()
		Super.OnInit()
	End Method

	Method ButtonClicked(event:wxCommandEvent)
		' Make the second Frame appear when this button is clicked
		Local frame2:MyFrame2 = MyFrame2(New MyFrame2.Create(,, "Frame 2"))

		frame2.show(True)
	End Method

End Type

Type MyFrame2 Extends MyFrame2Base
	Field frame2:MyFrame2

	Method OnInit()
		Super.OnInit()
	End Method

	Method Button2Clicked(event:wxCommandEvent)
		' ---------------------------------------------------------------------
		' How do i make the second Frame disappear when this button is clicked?
		' ---------------------------------------------------------------------
		frame2.show(False)
	End Method

End Type

testFormOpening_GUI.bmx

'
' BlitzMax code generated with wxCodeGen v1.06 : 05 Aug 2008 15:09:10
' 
' 
' PLEASE DO "NOT" EDIT THIS FILE!
' 
SuperStrict

Import wx.wxButton
Import wx.wxFrame
Import wx.wxPanel
Import wx.wxWindow


Type MyFrame1Base Extends wxFrame

	Field m_panel1:wxPanel
	Field m_button1:wxButton


	Method Create:MyFrame1Base(parent:wxWindow = Null,id:Int = wxID_ANY, title:String = "", x:Int = -1, y:Int = -1, w:Int = 500, h:Int = 300, style:Int = wxDEFAULT_FRAME_STYLE|wxTAB_TRAVERSAL)
		Return MyFrame1Base(Super.Create(parent, id, title, x, y, w, h, style))
	End Method

	Method OnInit()

		Local bSizer1:wxBoxSizer
		bSizer1 = New wxBoxSizer.Create(wxVERTICAL)
		m_panel1 = New wxPanel.Create(Self, wxID_ANY,,,,, wxTAB_TRAVERSAL)
		bSizer1.Add(m_panel1, 1, wxEXPAND | wxALL, 5)

		m_button1 = New wxButton.Create(Self, wxID_ANY, "MyButton")
		bSizer1.Add(m_button1, 0, wxALL, 5)

		SetSizer(bSizer1)
		Layout()

		m_button1.ConnectAny(wxEVT_COMMAND_BUTTON_CLICKED, _ButtonClicked, Null, Self)
	End Method

	Function _ButtonClicked(event:wxEvent)
		MyFrame1Base(event.sink).ButtonClicked(wxCommandEvent(event))
	End Function

	Method ButtonClicked(event:wxCommandEvent)
		DebugLog "Please override MyFrame1.ButtonClicked()"
		event.Skip()
	End Method

End Type

Type MyFrame2Base Extends wxFrame

	Field m_panel2:wxPanel
	Field m_button2:wxButton


	Method Create:MyFrame2Base(parent:wxWindow = Null,id:Int = wxID_ANY, title:String = "", x:Int = -1, y:Int = -1, w:Int = 500, h:Int = 300, style:Int = wxDEFAULT_FRAME_STYLE|wxTAB_TRAVERSAL)
		Return MyFrame2Base(Super.Create(parent, id, title, x, y, w, h, style))
	End Method

	Method OnInit()

		Local bSizer2:wxBoxSizer
		bSizer2 = New wxBoxSizer.Create(wxVERTICAL)
		m_panel2 = New wxPanel.Create(Self, wxID_ANY,,,,, wxTAB_TRAVERSAL)
		bSizer2.Add(m_panel2, 1, wxEXPAND | wxALL, 5)

		m_button2 = New wxButton.Create(Self, wxID_ANY, "MyButton2")
		bSizer2.Add(m_button2, 0, wxALL, 5)

		SetSizer(bSizer2)
		Layout()

		m_button2.ConnectAny(wxEVT_COMMAND_BUTTON_CLICKED, _Button2Clicked, Null, Self)
	End Method

	Function _Button2Clicked(event:wxEvent)
		MyFrame2Base(event.sink).Button2Clicked(wxCommandEvent(event))
	End Function

	Method Button2Clicked(event:wxCommandEvent)
		DebugLog "Please override MyFrame2.Button2Clicked()"
		event.Skip()
	End Method

End Type

Regards
glenn

Brucey

(Posted 2008) [#2]

The variable/field frame2 in your Button2Clicked method is Null. You never set it to anything.

Glenn Dodd

(Posted 2008) [#3]

true.
the question still remains though.
i want to unshow frame2 so frame1 reappears, or destroy frame2 if necessary, like clicking on the x in the top right hand corner.

I know this should be incredibly simple but ... i don't appear to be doing "simple" today.

Brucey

(Posted 2008) [#4]

I trust that your frames are just basic examples, as they are otherwise practically identical?

Anyhoo, how about :

	Method Button2Clicked(event:wxCommandEvent)
		Close()
	End Method

What were you intending your frame2 field in MyFrame2 to represent? itself, or a third frame?

Glenn Dodd

(Posted 2008) [#5]

i put the frame2 field in because it complained on the frame2.show(false) line without it.
amazingly the close() command on its own never even occurred to me.
i was trying to reference it back to itself in my previous attempts.

Many thanks