Android Question Reverse timer

[rezaghasmi]

How can I have a 30 second countdown timer?

 

[rezaghasmi]

Redone in B4A - Take into account Erel's comments about timers though

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Private xui As XUI
   
    Dim tmrCountdown As Timer
    Dim tmrSeconds As Int

End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    Private Button1 As B4XView
    Private Label1 As B4XView
   
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Layout")
   
    tmrCountdown.Initialize("tmr",1000)
    tmrCountdown.Enabled=False
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub Button1_Click
   
    tmrSeconds=30
   
    tmrCountdown.Enabled = True

End Sub

Sub tmr_tick
   
    tmrSeconds=tmrSeconds-1
    Label1.Text= tmrSeconds
   
    If tmrSeconds=0 Then tmrCountdown.Enabled=False
   
End Sub

After execution, the code leaves the page


java.lang.IllegalStateException: Interval must be larger than 0.
at anywheresoftware.b4a.objects.Timer.setEnabled(Timer.java:79)
at b4a.example.rgeg._activity_create(rgeg.java:482)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:191)
at b4a.example.rgeg.afterFirstLayout(rgeg.java:104)
at b4a.example.rgeg.access$000(rgeg.java:17)
at b4a.example.rgeg$WaitForLayout.run(rgeg.java:82)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7561)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:995)

 

[AnandGupta]

From @rezaghasmi screen-shots looks like he has opened a .b4j file in B4A.

Regards,

Anand

 

[Erel]

I use b4a Then writing CountDown becomes a red line

You need to understand what you are doing.

I recommend you to start here: https://www.b4x.com/android/documentation.html

 

[John Naylor]

After execution, the code leaves the page


java.lang.IllegalStateException: Interval must be larger than 0.
at anywheresoftware.b4a.objects.Timer.setEnabled(Timer.java:79)
at b4a.example.rgeg._activity_create(rgeg.java:482)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:191)
at b4a.example.rgeg.afterFirstLayout(rgeg.java:104)
at b4a.example.rgeg.access$000(rgeg.java:17)
at b4a.example.rgeg$WaitForLayout.run(rgeg.java:82)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7561)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:995)

You haven't set your interval correctly here I would guess

tmrCountdown.Initialize("tmr",1000)

 

[LucaMs]

The code I posted is a bit better.
1. It is very simple.
2. It is more accurate. Timers will never be 100% accurate as they run on the main thread. If the program is busy doing other stuff the counter will lag. With my code it will always stay accurate.

3. Does not need a global variable (the counter).

 

[John Naylor]

3. Does not need a global variable (the counter).

No, the counter stays inside the resumable sub. Erel really is a genius.

 

[LucaMs]

Erel really is a genius

Do not overdo it; actually he writes keywords and variables randomly but, since he's lucky, then his source works.


[and so it was that LucaMs was definitively banned ... and Mario was able to enter ]

 

[rezaghasmi]

Sub Tmr_Tick
 If ( counter > 0) Then
      counter = counter - 1
     Dim sMin As Int = Floor(counter / 60)
     Dim sSec As Int = counter Mod 60
      Dim secPrefix As String =""
     Dim minPrefix As String =""
      If (sSec < 10) Then
      secPrefix = "0"
     End If
     If (sMin < 10 ) Then
       minPrefix = "0"
     End If
     txtCounter.Text = minPrefix & sMin &":"& secPrefix & sSec
     Else
     t.Enabled = False
 End If
 
End Sub