B4J Question Beta 4.2 Error accessing MainForm

stevel05 · Feb 8, 2016

This one is driving me nuts!

An app I am using to test the beta has developed a strange issue when it does anything that accesses the main form but only in Debug mode, in release it runs fine.

Layouts load fine to the rootpane, but I am managing the form size, and trying to set it using:

B4X:

MainForm.WindowLeft = ScreenMetrics.GetDefault("left",10.0)
        MainForm.WindowTop = ScreenMetrics.GetDefault("top",10.0)
        MainForm.WindowWidth = ScreenMetrics.GetDefault("width",400.0)
        MainForm.WindowHeight = ScreenMetrics.GetDefault("height",300.0)

Gives me the error:

B4X:

Program started.
(MyMap) {height=639.0, spRightVdiv=0.5, width=816.0, left=432.0, top=124.0, spMainHdiv=0.5}
Error occurred on line: 116 (Main)
java.lang.NullPointerException
    at anywheresoftware.b4j.objects.Form.setWindowLeft(Form.java:152)
    at com.stevel05.snippetmanager.main._applyscreenmetrics(main.java:120)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:606)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:225)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:158)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:93)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:90)
    at anywheresoftware.b4a.BA.raiseEvent(BA.java:84)
    at com.stevel05.snippetmanager.main.start(main.java:36)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)

The map has valid values as you can see from the log.

If I bypass this code, I also get a different error when calling an fx.MsgBox elsewhere in the app:

B4X:

Program started.
Error occurred on line: 774 (Main)
java.lang.NullPointerException
    at anywheresoftware.b4j.objects.Form.getIcon(Form.java:279)
    at anywheresoftware.b4j.objects.JFX.setOwnerAndIcon(JFX.java:124)
    at anywheresoftware.b4j.objects.JFX.Msgbox2(JFX.java:168)
    at com.stevel05.snippetmanager.main._clearsnippet(main.java:720)
    at com.stevel05.snippetmanager.main._btnclearsnippet_action(main.java:756)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:606)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:228)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:158)
    at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:93)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:90)
    at anywheresoftware.b4a.BA$2.run(BA.java:165)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)

I did have a custom icon set on the form, which I have removed after seeing this message for the first time but it made no difference.

I have tried:

Cleaning the project
Closing and reopening the IDE
Creating a new project and copying all the modules across.
Reinstalling B4j into an empty directory.
Moved the Window update to a callsubdelayed from the Appstart sub

The last try gives me this code:

B4X:

    Log(MainForm.Height)
    'At the end of AppStart
    Log(MainForm.Height)                                                       'This call works
    CallSubDelayed(Me,"ApplyScreenMetrics")
    CallSubDelayed(Me,"SetupComplete")
End Sub


Sub ApplyScreenMetrics
'    Log(PackageName)
    If File.Exists(File.DirData(PackageName),"screen.m") Then
        Log(MainForm.Height)                                                    'This one fails
        Log(MainForm.WindowLeft)
        ScreenMetrics = File.ReadMap(File.DirData(PackageName),"screen.m")
        Log(ScreenMetrics)
        MainForm.WindowLeft = ScreenMetrics.GetDefault("left",10.0)
        MainForm.WindowTop = ScreenMetrics.GetDefault("top",10.0)
        MainForm.WindowWidth = ScreenMetrics.GetDefault("width",400.0)
        MainForm.WindowHeight = ScreenMetrics.GetDefault("height",300.0)
        spMain.DividerPositions = Array As Double(ScreenMetrics.GetDefault("spMainHdiv",0.5))
        spRight.DividerPositions = Array As Double(ScreenMetrics.GetDefault("spRightVdiv",0.1))
    Else
        ScreenMetrics.Initialize
    End If
End Sub

Error from the second Log(MainForm.Height)

B4X:

Program started.
600
Error occurred on line: 116 (Main)
java.lang.NullPointerException
    at anywheresoftware.b4j.objects.Form.getHeight(Form.java:234)
    at com.stevel05.snippetmanager.main._applyscreenmetrics(main.java:114)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:606)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:225)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:158)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:93)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:90)
    at anywheresoftware.b4a.keywords.Common.CallSub4(Common.java:462)
    at anywheresoftware.b4a.keywords.Common.access$0(Common.java:442)
    at anywheresoftware.b4a.keywords.Common$CallSubDelayedHelper.run(Common.java:516)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)

These errors only occur in Debug mode, I am wondering if it may be a memory issue, but that's not what the logs say. The project is a reasonable size, but I wouldn't say it's huge. It does use a few libraries, but not really any more than my usual projects.

I can't easily try putting it into v4 as it is using a Custom View.

I can't get it to fail in a simple project, but I'm out of ideas where to look.

Erel · Feb 8, 2016

It is not a memory issue.

Can you upload the project or send it to my by mail?

stevel05 · Feb 8, 2016

Thanks Erel,

I've also included a couple of libraries that you will need and may not have installed.

The easiest way to get it to fail (it won't load the metric file on first run), is to select the bottom right snippet code pane, type anything, then click clear, this will try to open a msgbox.

I am sending to an additional jar file as it's too large to post.

stevel05 · Feb 8, 2016

I've sent you a link to it on my dropbox as GMail wouldn't let me send a jar file

Erel · Feb 8, 2016

Your code uses MainForm before it is set. It happens in LoadDataBase sub which is called before MainForm is set.

Move the line that sets MainFor = Form1 before the call to LoadDataBase and it should work.

There is a bug in the debugger here. I'm investigating it.

stevel05 · Feb 8, 2016

I just couldn't see it this time. A slip of the Ctrl-V in the wrong place. Many thanks Erel.

That's 5 hours of community support on the forum I owe

Erel · Feb 8, 2016

stevel05 said:
That's 5 hours of community support on the forum I owe

I'm afraid that it is not the case here. Your code has revealed an hard to reproduce debugger bug. So actually you gained 5 hours of extra community privileges

B4J Question Beta 4.2 Error accessing MainForm

stevel05

Expert

Erel

B4X founder

stevel05

Expert

stevel05

Expert

Erel

B4X founder

stevel05

Expert

Erel

B4X founder

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