Maui android app Compile error: namespace name 'Java' could not be found

Question

Maui android app Compile error: namespace name 'Java' could not be found

Haviv Elbsz 2,071

Hi all

My project is build and run
but I have 2 problems

Although the app builds and run fine I get the following error:

Severity Code Description Project File Line Suppression State Error CS0246

The type or namespace name 'Java' could not be found
(are you missing a using directive or an assembly reference?)

RazKmoShed (net7.0-ios), RazKmoShed (net7.0-maccatalyst),
RazKmoShed (net7.0-windows10.0.19041.0)
C:_nx11_._Dev\maui\RazKmoShed\RazKmoShed\MainPage.xaml.cs 19 Active

2 . In the running app I have 2 scroll sections
the first responds as expected scroll
horizontally and verticaliy. the second section scroll only vertically

This is the section that respond ok

   <ScrollView Orientation="Vertical" HeightRequest="250"  
                   BackgroundColor="OldLace"  
                   VerticalScrollBarVisibility="Always" >  
               <ScrollView Orientation="Horizontal"  
                   HorizontalScrollBarVisibility="Always" >  
                       <Label x:Name="OutputTB1" Text=""  
                            FontSize="16"  
                            TextColor="Black"  
                            FontAttributes="Bold"  
                            FontFamily="NCourier"  
                            MinimumWidthRequest="-1"  
                             >  
                       </Label>  
               </ScrollView>  
           </ScrollView>

This is the section that not respond ok

   <ScrollView x:Name="scroll" HeightRequest="450" Orientation="Vertical"  
                           BackgroundColor="LightGreen" VerticalScrollBarVisibility="Always" >  
                   <ScrollView Orientation="Horizontal"  
                               HorizontalScrollBarVisibility="Always" >  
                       <Label  x:Name="OutputTB" Text=""  
                            FontSize="16"  
                            TextColor="Black"  
                            FontAttributes="Bold"  
                            FontFamily="NCourier"  
                            MinimumWidthRequest="-1"  
                             >  
                       </Label>  
     
                   </ScrollView>  
               </ScrollView>

This is my xaml code:

   <?xml version="1.0" encoding="utf-8" ?>  
   <!-- 16_26112022 -->  
   <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"  
                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"  
                x:Class="RazKmoShed.MainPage" Loaded="MainPage_Loaded" x:Name="myContentPage"  
                FlowDirection="LeftToRight" BackgroundColor="Azure" >  
     
       <ScrollView x:Name="topscroll">  
           <VerticalStackLayout x:Name="vLayout" Margin="10" Spacing="5" >  
     
               <Picker x:Name="ExamplesCombo" SelectedIndexChanged="ExamplesCombo_SelectedIndexChanged"  
                           HorizontalTextAlignment="Center" BackgroundColor="Chartreuse"  
                           Title="Select Help Example" TitleColor="Black" FontAttributes="Bold" >  
                   <Picker.ItemsSource>  
                       <x:Array Type="{x:Type x:String}">  
                           <x:String>Mul    Example 1</x:String>  
                           <x:String>Mul    Example 2</x:String>  
                           <x:String>Mul    Example 3</x:String>  
                           <x:String>Mul    Example 4</x:String>  
                           <x:String>Mul    Example 5</x:String>  
                           <x:String>Mul    Example 6</x:String>  
                           <x:String>Mul    Example 7</x:String>  
                           <x:String>Mul    Example 8</x:String>  
                           <x:String>Mul    Example 9</x:String>  
                           <x:String>Mul    Example 10</x:String>  
                           <x:String>Mul    Example 11</x:String>  
                           <x:String>Div    Example 1</x:String>  
                           <x:String>Div    Example 2</x:String>  
                           <x:String>Div    Example 3</x:String>  
                           <x:String>Div    Example 4</x:String>  
                           <x:String>Div    Example 5</x:String>  
                           <x:String>Div    Example 6</x:String>  
                           <x:String>Div    Example 7</x:String>  
                           <x:String>Div    Example 8</x:String>  
                           <x:String>Div    Example 9</x:String>  
                           <x:String>Div    Example 10</x:String>  
                           <x:String>Div    Example 11</x:String>  
                           <x:String>Div    Example 12</x:String>  
                           <x:String>Div    Example 13</x:String>  
                           <x:String>Div    Example 14</x:String>  
                           <x:String>AddSub Example 1</x:String>  
                           <x:String>AddSub Example 2</x:String>  
                           <x:String>Add    Example 1</x:String>  
                           <x:String>Add    Example 2</x:String>  
                           <x:String>Add    Example 3</x:String>  
                           <x:String>Add    Example 4</x:String>  
                           <x:String>Sub    Example 1</x:String>  
                           <x:String>Sub    Example 2</x:String>  
                           <x:String>Sqr    Example 1</x:String>  
                           <x:String>Sqr    Example 2</x:String>  
                       </x:Array>  
                   </Picker.ItemsSource>  
               </Picker>  
     
               <Picker x:Name="ShortOPCombo" SelectedIndexChanged="ShortOPCombo_SelectedIndexChanged"  
                           HorizontalTextAlignment="Center" BackgroundColor="Pink"  
                           Title="Select Puzzle Type" TitleColor="Black" FontAttributes="Bold" >  
                   <Picker.ItemsSource>  
                       <x:Array Type="{x:Type x:String}">  
                           <x:String>Mul Puzzle</x:String>  
                           <x:String>Div Puzzle</x:String>  
                           <x:String>AddSub Puzzle</x:String>  
                           <x:String>Add Puzzle</x:String>  
                           <x:String>Sub Puzzle</x:String>  
                           <x:String>Sqr Puzzle</x:String>  
                       </x:Array>  
                   </Picker.ItemsSource>  
               </Picker>  
     
               <Picker x:Name="nonParticipantcombo" SelectedIndexChanged="nonParticipantcombo_SelectedIndexChanged"  
                           HorizontalTextAlignment="Center" BackgroundColor="Orange"  
                           Title="Select Non Participants Digits" TitleColor="Black" FontAttributes="Bold" >  
                   <Picker.ItemsSource>  
                       <x:Array Type="{x:Type x:String}">  
                           <x:String>Use Any Non Participants Digits</x:String>  
                           <x:String>Use 0 Non Participants Digits</x:String>  
                           <x:String>Use 1 Non Participants Digits</x:String>  
                           <x:String>Use 2 Non Participants Digits</x:String>  
                           <x:String>Use 3 Non Participants Digits</x:String>  
                           <x:String>Use 4 Non Participants Digits</x:String>  
                           <x:String>Use 5 Non Participants Digits</x:String>  
                           <x:String>Use 6 Non participants Digits</x:String>  
                           <x:String>Use 7 Non participants Digits</x:String>  
                           <x:String>Use 8 Non participants Digits</x:String>  
                           <x:String>Use 9 Non participants Digits</x:String>  
                       </x:Array>  
                   </Picker.ItemsSource>  
               </Picker>  
     
           <ScrollView Orientation="Vertical" HeightRequest="250"  
                   BackgroundColor="OldLace"  
                   VerticalScrollBarVisibility="Always" >  
               <ScrollView Orientation="Horizontal"  
                   HorizontalScrollBarVisibility="Always" >  
                       <Label x:Name="OutputTB1" Text=""  
                            FontSize="16"  
                            TextColor="Black"  
                            FontAttributes="Bold"  
                            FontFamily="NCourier"  
                            MinimumWidthRequest="-1"  
                             >  
                       </Label>  
               </ScrollView>  
           </ScrollView>  
     
     
               <HorizontalStackLayout >  
                   <CheckBox x:Name="L2RAlfaBetCKB" IsChecked="False"  
                         CheckedChanged="L2RAlfaBetCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="Checked = RightToLeft Writing" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <Editor x:Name="InputTB"   
                           BackgroundColor="LightSkyBlue" FontSize="16" FlowDirection="LeftToRight"  
                           TextChanged="InputTB_TextChanged" TextColor="Black"  
                           Placeholder=""  
                           FontAttributes="Bold"  
                           PlaceholderColor="Blue" FontFamily="NCourier"  
                           HorizontalOptions="Fill" VerticalOptions="Start"   
                           HeightRequest="500" WidthRequest="320" >  
               </Editor>  
     
               <HorizontalStackLayout >  
                   <CheckBox x:Name="useDigitsItselfCKB" IsChecked="False"  
                         CheckedChanged="useDigitsItselfCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="Use Digit Itself Value" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout >  
                   <CheckBox x:Name="alphaCKB" IsChecked="False"  
                         CheckedChanged="alphaCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="Alpha Free" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout >  
                   <CheckBox x:Name="fromToCKB" IsChecked="False"  
                         CheckedChanged="fromToCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="Asterisk Free" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout >  
                   <CheckBox x:Name="UseOddsEvensCKB" IsChecked="False"  
                         CheckedChanged="UseOddsEvensCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="EO Use Evens and Odds" FontAttributes="Bold"           
                         HorizontalOptions="Start" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout >  
                   <CheckBox x:Name="shiftingsCKB" IsChecked="False"  
                         CheckedChanged="shiftingsCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="Use Terms Shiftings" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout Spacing="10" >  
                   <CheckBox x:Name="ZerosCKB" IsChecked="False"  
                         CheckedChanged="ZerosCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label    Text="Remove Zero Terms >" FontAttributes="Bold"           
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
                   <Entry   x:Name="MaxZeroTermsTB" HorizontalOptions="FillAndExpand"  
                            BackgroundColor="Cyan"  MinimumWidthRequest="300" FontAttributes="Bold"                   
                            Text="0    " TextChanged="MaxZeroTermsTB_TextChanged" />  
     
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout Spacing="10" >  
                   <CheckBox x:Name="UseFromDigitsCKB" IsChecked="False"  
                         CheckedChanged="UseFromDigitsCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label Text="Use These Digits ==>" FontAttributes="Bold"           
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
                   <Entry   x:Name="UseFromDigitsTB" HorizontalOptions="FillAndExpand"  
                            BackgroundColor="Cyan" MinimumWidthRequest="300" FontAttributes="Bold"                   
                            Text="*4 1 2 3 4    " TextChanged="UseFromDigitsTB_TextChanged" />  
     
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout Spacing="10" >  
                   <CheckBox x:Name="UseRepetitionCKB" IsChecked="False"  
                         CheckedChanged="UseRepetitionCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label Text="Use Digit Repeat ==>" FontAttributes="Bold"           
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
     
                   <Entry   x:Name="UseRepetitionTB" HorizontalOptions="FillAndExpand"  
                            BackgroundColor="Cyan"  MinimumWidthRequest="300" FontAttributes="Bold"                   
                            Text="= 24    " TextChanged="UseRepetitionTB_TextChanged" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout Spacing="10" >  
                   <CheckBox x:Name="TermsDiffDigitsCKB" IsChecked="False"  
                         CheckedChanged="TermsDiffDigitsCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label Text="Use Terms Diff Digits ==>" FontAttributes="Bold"           
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
                   <Entry   x:Name="TermsDiffDigitsTB" HorizontalOptions="FillAndExpand"  
                            BackgroundColor="Cyan"  MinimumWidthRequest="300" FontAttributes="Bold"                   
                            Text="= 2 0 ! 3 1 = 4 2    " TextChanged="TermsDiffDigitsTB_TextChanged" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout Spacing="10" >  
                   <CheckBox x:Name="NCommonCKB" IsChecked="False"  
                         CheckedChanged="NCommonCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
     
                   <Label Text="Use Terms nCommon ==>" FontAttributes="Bold"           
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
                   <Entry   x:Name="NCommonTB" HorizontalOptions="FillAndExpand"  
                            BackgroundColor="Cyan"  MinimumWidthRequest="300" FontAttributes="Bold"                   
                            Text="0 2 0 1 2 3    " TextChanged="NCommonTB_TextChanged" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout Spacing="10" >  
                   <Label HorizontalOptions="Start" VerticalOptions="Center"  
                          FontAttributes="Bold"  
                          Text="Calculation Number System Base" />  
     
                   <Entry   x:Name="baseXTB"  HorizontalOptions="FillAndExpand" Text="10    "  
                            BackgroundColor="Cyan"  MinimumWidthRequest="300" FontAttributes="Bold"  
                            TextChanged="baseXTB_TextChanged" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
                 
               <HorizontalStackLayout >  
                   <Label    Text="Keep Last Solutions" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
                   <CheckBox x:Name="KeepSolutionsCKB" IsChecked="False"  
                         CheckedChanged="KeepSolutionsCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <HorizontalStackLayout >  
                   <Label    Text="Show Help / Clear Help" FontAttributes="Bold"  
                         HorizontalOptions="Start" VerticalOptions="Center" />  
     
                   <CheckBox x:Name="ShowHelpCKB" IsChecked="False"  
                         CheckedChanged="ShowHelpCKB_CheckedChanged"  
                         HorizontalOptions="Center" VerticalOptions="Center" />  
               </HorizontalStackLayout>  
     
               <ScrollView x:Name="scroll" HeightRequest="450" Orientation="Vertical"  
                           BackgroundColor="LightGreen" VerticalScrollBarVisibility="Always" >  
                   <ScrollView Orientation="Horizontal"  
                               HorizontalScrollBarVisibility="Always" >  
                       <Label  x:Name="OutputTB" Text=""  
                            FontSize="16"  
                            TextColor="Black"  
                            FontAttributes="Bold"  
                            FontFamily="NCourier"  
                            MinimumWidthRequest="-1"  
                             >  
                       </Label>  
     
                   </ScrollView>  
               </ScrollView>  
     
               <ProgressBar x:Name="progressBar"  Progress="0"  
                            ProgressColor="Blue" BackgroundColor="Aqua" />  
     
               <Button  x:Name="RunButton" Text="Start" BackgroundColor="#512BD4"  
                         HorizontalOptions="Center" VerticalOptions="Center"  
                         CornerRadius="20" BorderColor="Black" TextColor="White"  
                         BorderWidth="2" HeightRequest="40" WidthRequest="140"  
                         Clicked="RunButton_Clicked" FontAttributes="Bold" />  
                             
               <Label HorizontalOptions="Center" VerticalOptions="Center"  
                          FontAttributes="Bold"  
                          Text="Solutions Window" />  
     
           </VerticalStackLayout>  
       </ScrollView>  
     
   </ContentPage>

Help me to fix these problems

Thank you very much

Haviv Elbsz 2,071 Reputation points

2022-11-29T10:45:49.917+00:00

I tried build 5 times again
snd the error not appear again

but when the app run

the first section respond vertically and horizontally scrolling

buy the second section scroll only vertically
Haviv Elbsz 2,071 Reputation points

2022-12-06T09:18:29.223+00:00

When I set with my self and thinking why vertically scrolling working and horizontally scrolling not working..

I noticed that I was setting the widthrequest of the horizontal stack layout

so I removed this
setting
and now itd working

This mysterious for me

thank you very much
Anonymous

2022-12-07T08:37:56.5+00:00

Thanks for your sharing.
Haviv Elbsz 2,071 Reputation points

2022-12-07T09:21:53.527+00:00

you help me to get it

how I can relate this answer to you

thank you very much
Anonymous

2022-12-07T09:30:08.437+00:00

how I can relate this answer to you

I convert my comment to answer and add your solution.

Accepted answer

0 additional answers

Your answer

Haviv Elbsz 2,071 Reputation points

2022-11-29T10:45:49.917+00:00

I tried build 5 times again
snd the error not appear again

but when the app run

the first section respond vertically and horizontally scrolling

buy the second section scroll only vertically
Haviv Elbsz 2,071 Reputation points

2022-12-06T09:18:29.223+00:00

When I set with my self and thinking why vertically scrolling working and horizontally scrolling not working..

I noticed that I was setting the widthrequest of the horizontal stack layout

so I removed this
setting
and now itd working

This mysterious for me

thank you very much
Anonymous

2022-12-07T08:37:56.5+00:00

Thanks for your sharing.
Haviv Elbsz 2,071 Reputation points

2022-12-07T09:21:53.527+00:00

you help me to get it

how I can relate this answer to you

thank you very much
Anonymous

2022-12-07T09:30:08.437+00:00

how I can relate this answer to you

I convert my comment to answer and add your solution.

Answer 1

Anonymous

I tested your code, two nested scrollview could be scrolled vertically and horizontally.
Do you have too much character in your scrollview? Please add following text in label to your Scrollview, is that working?
Which platform is not working when running code?
Please share your MAUI and VS version.
Try to remove the widthrequest of the horizontal stack layout.

265535-testtext.txt

Haviv Elbsz 2,071 Reputation points

2022-11-30T05:45:18.207+00:00

Hi Leon Lu and thank you very much

I added that text and still scroll vertically only.
Please help me because I am upset of this
Note that I tried it many times.

I use this versions

Microsoft Visual Studio Community 2022 (64-bit) - Preview
Version 17.5.0 Preview 1.0
net 7
and this emulator

Pixel 5 API 33 (Android 13.0 - API33)
Anonymous

2022-11-30T06:35:19.24+00:00

Please create an emulator with API 31 to make a test, I found API 33 have a system back gesture when you scroll horizontally.

When you scroll horizontally and vertically, please release your finger when switch scroll horizontally to scroll vertically
Haviv Elbsz 2,071 Reputation points

2022-11-30T07:22:01.01+00:00

Hi Leon Lu

I set emulator to API 31
and scroll with release my finger when switch scroll horizontally to scroll vertically
and still the
first label section scrolls horizontally and vertically.

but the second label second still refuse to scroll horizontally.
that make me upset because they are the same.

Please try think for a solution

I am very thanking you
Anonymous

2022-11-30T07:37:57.19+00:00

Could you share a demo with us? Because I copy your code and run it with same VS and android version, it is working in my side.
Haviv Elbsz 2,071 Reputation points

2022-11-30T14:04:51.66+00:00

here a live share I hope I did it correctly

https://prod.liveshare.vsengsaas.visualstudio.com/join?3A6105A64E80727471FD4AEA7ECB9D249620

thanks
Anonymous

2022-12-01T06:25:13.547+00:00

I cannot open it, for your scenario, it is recommended to open a support ticket for this. Please contact our paid phone support at MS Support. You will get 1:1 support on that.
Haviv Elbsz 2,071 Reputation points

2022-12-01T07:47:59.633+00:00

is there a way to send you a zip file
Anonymous

2022-12-01T07:51:17.28+00:00

You can create a minimize demo, then upload your demo in the GitHub and share this link here.
Haviv Elbsz 2,071 Reputation points

2022-12-01T18:02:13.38+00:00

Is this OK

https://github.com/ehaviv/RazKmoShed
Haviv Elbsz 2,071 Reputation points

2022-12-04T13:49:48.197+00:00

Hi Leon LU

If needed additional things

please direct me and I will do

Thank you very much
Anonymous

2022-12-05T08:28:31.74+00:00

I open this GitHub link, I get alert about This repository is empty.
Haviv Elbsz 2,071 Reputation points

2022-12-05T10:59:45.02+00:00

Hi Leon Lu

I read help and tried my best
So I don't know how to fix that

any way thank you very much

I step by step rewrite my app
with steps observing
Anonymous

2022-12-06T08:26:47.647+00:00

Ok, thanks for your update.

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Maui android app Compile error: namespace name 'Java' could not be found

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