Android Question TabStripViewPager

D

DawningTruth

Active Member
Licensed User
My B4A was working fine. I recently upgraded.

Now it will not run TabStripPageViewer.

I get the following error message from the attached sample code:

java.lang.ClassNotFoundException: android.support.v4$view$ViewPager$OnPageChangeListener
at anywheresoftware.b4j.object.JavaObject.getCorrectClassName(JavaObject.java:288)
at anywheresoftware.b4j.object.JavaObject.createEvent(JavaObject.java:252)
at anywheresoftware.b4j.object.JavaObject.CreateEventFromUI(JavaObject.java:222)
at b4a.example.webbrowser._setuppagechangelistener(webbrowser.java:1812)
at b4a.example.webbrowser._activity_resume(webbrowser.java:1796)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at b4a.example.webbrowser.afterFirstLayout(webbrowser.java:112)
at b4a.example.webbrowser.access$000(webbrowser.java:19)
at b4a.example.webbrowser$WaitForLayout.run(webbrowser.java:84)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:101)
at android.os.Looper.loop(Looper.java:166)
at android.app.ActivityThread.main(ActivityThread.java:7523)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)

Any thoughts on what to do?
 

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  • TabStrip.zip
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walterf25

walterf25

Expert
Licensed User
Longtime User
DawningTruth said:
My B4A was working fine. I recently upgraded.

Now it will not run TabStripPageViewer.

I get the following error message from the attached sample code:

java.lang.ClassNotFoundException: android.support.v4$view$ViewPager$OnPageChangeListener
at anywheresoftware.b4j.object.JavaObject.getCorrectClassName(JavaObject.java:288)
at anywheresoftware.b4j.object.JavaObject.createEvent(JavaObject.java:252)
at anywheresoftware.b4j.object.JavaObject.CreateEventFromUI(JavaObject.java:222)
at b4a.example.webbrowser._setuppagechangelistener(webbrowser.java:1812)
at b4a.example.webbrowser._activity_resume(webbrowser.java:1796)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at b4a.example.webbrowser.afterFirstLayout(webbrowser.java:112)
at b4a.example.webbrowser.access$000(webbrowser.java:19)
at b4a.example.webbrowser$WaitForLayout.run(webbrowser.java:84)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:101)
at android.os.Looper.loop(Looper.java:166)
at android.app.ActivityThread.main(ActivityThread.java:7523)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)

Any thoughts on what to do?
Click to expand...
Open up the SDK Manager and search for ViewPager and install.

Walter
 
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D

DawningTruth

Active Member
Licensed User
Thx, tried the above advice and still get an error. Here is a screenshot:

1583989770967.png
 
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Erel

Erel

B4X founder
Staff member
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Longtime User
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D

DawningTruth

Active Member
Licensed User
Thx @Erel

Tried the advice provided.

It now works with the standard example project.

When I add in support for Page Change Listening, the error recurs.

B4X: 
    Dim jo As JavaObject = TabStrip1
    Dim event As Object = jo.CreateEventFromUI("android.support.v4.view.ViewPager.OnPageChangeListener", "PageChangeListener", Null)
    jo.GetFieldJO("tabStrip").RunMethod("setOnPageChangeListener", Array(event))
    
    
    Sub PageChangeListener_Event (MethodName As String, Args() As Object) As Object
    'Log("Method: " & MethodName)
    
    If MethodName = "onPageSelected" Then
        Log("Method: " & MethodName)
        Dim ArgsList As List = Args
        Log ("Index: "&ArgsList.Get(0))
        'Log("Args: " & ArgsList)
    End If
    
    'Log("Current Position: "&currentPosition)
    
    Return Null
End Sub

Here is the error:


*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
after
Error occurred on line: 74 (Main)
java.lang.ClassNotFoundException: android.support.v4$view$ViewPager$OnPageChangeListener
at anywheresoftware.b4j.object.JavaObject.getCorrectClassName(JavaObject.java:288)
at anywheresoftware.b4j.object.JavaObject.createEvent(JavaObject.java:252)
at anywheresoftware.b4j.object.JavaObject.CreateEventFromUI(JavaObject.java:222)
at b4a.example3.main$ResumableSub_Activity_Create.resume(main.java:661)
at anywheresoftware.b4a.shell.DebugResumableSub$DelegatableResumableSub.resumeAsUserSub(DebugResumableSub.java:48)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:732)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:351)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:255)
at java.lang.reflect.Method.invoke(Native Method)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:144)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:180)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
at anywheresoftware.b4a.shell.DebugResumableSub$DelegatableResumableSub.resume(DebugResumableSub.java:43)
at anywheresoftware.b4a.keywords.Common$13.run(Common.java:1705)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:101)
at android.os.Looper.loop(Looper.java:166)
at android.app.ActivityThread.main(ActivityThread.java:7523)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)
** Activity (main) Pause, UserClosed = true **

This is the line 74 referred to in the error:

B4X: 
Dim event As Object = jo.CreateEventFromUI("android.support.v4.view.ViewPager.OnPageChangeListener", "PageChangeListener", Null)

I have tried to run the Jetifier but it gives me the following:

1583999647891.png


And the file is in the Additional Libraries folder:

1583999699637.png

Any other suggestions?
 
Upvote 0
D

DawningTruth

Active Member
Licensed User
@Erel It's absolutely necessary as it forms the core of my app. Have already spent months using this code to build a customer lazy loader for the TabStrip. I need to track swipe directions, which tab is currently active and a whole host of other actions. It is a couple of thousand lines of code.

And I'm speaking to investors next week to show them the first demo of my app. No pressure :eek:

It was based on this original code:

Custom PageChangeListener_Event Parameters

With reference to this post: https://www.b4x.com/android/forum/threads/tabstrip-access-events.80845/#post-512196 I have tried to get the sample code working on the demo TabStripViewPager app. Sub Activity_Create(FirstTime As Boolean) Activity.LoadLayout("Main")...
www.b4x.com www.b4x.com

I went through the source on my main app again and these are the specific events I'm using:

B4X: 
Sub PageChangeListener_Event (MethodName As String, Args() As Object) As Object
    
    'Handle Scroll event
    If MethodName = "onPageScrolled" Then
            
    '###### Process onPageScrolled Data Here ######
        
    End If
    
    'Handle Page Change Event
    If MethodName = "onPageSelected" Then
            
    '###### Process onPageSelected Events Here ######
            
    End If
    
    Return Null

End Sub
 
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