Stop Home button exiting Application

LisaM · Apr 13, 2013

Hi,

Is it possible to stop my application from closing when the home button is pressed using B4A? and if so does it matter if it is a physical home button? the reason is i am building and educational app for my 2 yr old and would like to be able to stop him from accidentally exiting the app and consequently accessing other areas of my phone. I have added another way of exiting the application by long clicking on a button on the home screen which makes visible a quit button
I have had a search and found how to trap the back button from exiting but it does not work for my home button.

Also I use this code to switch between layouts using the 1 activity. Is there a better way to write this code as it seems very slow the further i progress through the layouts. Maybe using a for each loop? if so how would i write it?
I did try using the sliding panels code but could not get it to work using layouts.

this is the button event

B4X:

Dim counter As Int
Dim counterpage As Int

B4X:

Sub Button2_Click
   counterpage = counter + 1
   counteraspage
   counter = counterpage   
End Sub

Sub Button1_Click
   counterpage = counter - 1
   counteraspage
   counter = counterpage
End Sub

this sets the layout dependant on the counterpage value

B4X:

Sub counteraspage
   If counterpage = 0 Then
   Activity.LoadLayout("A")
   End If
   If counterpage = 1 Then
   Activity.LoadLayout("B")
   End If
   If counterpage = 2 Then
   Activity.LoadLayout("C")
   End If
   If counterpage = 3 Then
   Activity.LoadLayout("D")
   End If
   If counterpage = 4 Then
   Activity.LoadLayout("E")
   End If
   If counterpage = 5 Then
   Activity.LoadLayout("F")
   End If
   If counterpage = 6 Then
   Activity.LoadLayout("G")
   End If
   If counterpage = 7 Then
   Activity.LoadLayout("H")
   End If
   If counterpage = 8 Then
   Activity.LoadLayout("I")
   End If
   If counterpage = 9 Then
   Activity.LoadLayout("J")
   End If
   If counterpage = 10 Then
   Activity.LoadLayout("K")
   End If
   If counterpage = 11 Then
   Activity.LoadLayout("L")
   End If
   If counterpage = 12 Then
   Activity.LoadLayout("M")
   End If
   If counterpage = 13 Then
   Activity.LoadLayout("N")
   End If
   If counterpage = 14 Then
   Activity.LoadLayout("O")
   End If
   If counterpage = 15 Then
   Activity.LoadLayout("P")
   End If
   If counterpage = 16 Then
   Activity.LoadLayout("Q")
   End If
   If counterpage = 17 Then
   Activity.LoadLayout("R")
   End If
   If counterpage = 18 Then
   Activity.LoadLayout("S")
   End If
   If counterpage = 19 Then
   Activity.LoadLayout("T")
   End If
   If counterpage = 20 Then
   Activity.LoadLayout("U")
   End If
   If counterpage = 21 Then
   Activity.LoadLayout("V")
   End If
   If counterpage = 22 Then
   Activity.LoadLayout("W")
   End If
   If counterpage = 23 Then
   Activity.LoadLayout("X")
   End If
   If counterpage = 24 Then
   Activity.LoadLayout("Y")
   End If
   If counterpage = 25 Then
   Activity.LoadLayout("Z")
   End If
   If counterpage > 25 Then
   Activity.LoadLayout("A")
   counterpage = 0
   counter = 0
   End If
End Sub

any help appreciated thnx

NJDude · Apr 13, 2013

The HOME key cannot be captured.

mangojack · Apr 13, 2013

Here's my two cents worth .. and there might be a more efficient method. Only tested with 3 layouts . How do you stop counterpage reducing past 0 ?

B4X:

Sub Process_Globals
      
   Dim alpha As String    :alpha = "ABCDEFJHIJKLMNOPQRSTUVWXYZ"
   
End Sub

Sub Globals

   Dim Button2 As Button
   Dim Button1 As Button
   Dim counterpage As Int

End Sub
   
Sub Button1_Click
    'if counterpage = 0 then Return   'might be neccessary   
    counterpage = counterpage - 1
    GetLayout(counterpage)
End Sub

Sub Button2_Click
    counterpage = counterpage + 1
    GetLayout(counterpage)
End Sub

Sub GetLayout(nPage As Int)
    
   If nPage > 25 Then 
      counterpage = 0           
      nPage = 0               
   End If
   
   Dim  nLayout As String
   nLayout = alpha.CharAt(nPage)
    Activity.LoadLayout(nLayout)

End Sub

Cheers mj

yttrium · Apr 13, 2013

You will never be able to capture the Home button. This isn't a limitation of Basic4Android, it's an intended limitation in Android (to stop misbehaving apps from taking complete control).

Erel · Apr 13, 2013

See this discussions:
Basic4android Search: Kiosk

LisaM · Apr 16, 2013

Thanks for all the great reply's
I wonder how Kids Mode by Zoodles does it then cause they have prevented the home button from exiting the app. Not that it matters it was just a query.

They code you posted looks great so much easier I will test it out and it teaches me alot thank you very much.

In the meantime i just ended up using the 1 layout and just changing the label.txt and imageview.setbackgroundimage dependant on the counter no.

if the counter went past 0 i put this code in.

B4X:

   If counterpage < 0 Then
   Label1.Text = "Z"
   ImageView1.SetBackgroundImage(LoadBitmap(File.DirAssets,"Zalmoxes.png"))
   Label3.Text = "Zalmoxes"
   Label3.Top = 75%y
   counter = 25
   counterpage = 25
   End If

so it just ends up in a loop

thank you everyone here is so helpful its great :icon_clap:

Stop Home button exiting Application

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