小编Raj*_*zer的帖子

更新到 Xamarin.Forms 4.8 后，我在应用程序启动时收到此错误：

Java.Lang.NoSuchMethodError: 'No static method checkBuilderRequirement(Ljava/lang/Object;Ljava/lang/Class;)V in class Ldagger/internal/Preconditions; or 
its super classes (declaration of 'dagger.internal.Preconditions' appears in /data/app/com.codex.MojLek-
ELK-GTa_ywWpF5Na88sJeQ==/base.apk)'

如何解决这个问题？

这是我的代码

<ListView x:Name="listViewClient"  ItemsSource="{Binding Client}" HasUnevenRows="True">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <ViewCell >


                        <Grid  Margin="10">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="5"/>
                                <ColumnDefinition />
                            </Grid.ColumnDefinitions>
                            <BoxView  Grid.Column="0" Color="#84DCC6"/>
                            <StackLayout Grid.Column="1" Padding="20, 10">

                                <Frame BorderColor="WhiteSmoke">
                                    <StackLayout>
                                <Label Text="Name:" FontSize="16" />
                                <Label FontSize="Medium" Text="{Binding Name}" FontAttributes="Bold" />
                                    </StackLayout>
                                </Frame>
                                <Frame BorderColor="WhiteSmoke">
                                    <StackLayout>
                                    <Label Text="Adress:"  FontSize="16"/>
                                <Label FontSize="Medium" Text="{Binding Adress}" FontAttributes="Bold"/>
                                    </StackLayout>
                                </Frame>
                                <Frame BorderColor="WhiteSmoke">
                                    <StackLayout>
                                    <Label Text="Place:"  FontSize="16"/>
                                    <Label FontSize="Medium" Text="{Binding Place}" FontAttributes="Bold" />
                                    </StackLayout>
                                </Frame>

                                <Frame BorderColor="WhiteSmoke" >
                                    <Grid >

                                    <StackLayout Grid.Column="0">
                                    <Label Text="Mobile:"  FontSize="16"/>
                                    <Label  FontSize="Medium" Text="{Binding …

我有一个简单的表单，用户可以在其中添加电子邮件：

                       <Entry Placeholder="Email" Text="{Binding Email}">
                            <Entry.Behaviors>
                                <xct:MultiValidationBehavior >
                                    <xct:EmailValidationBehavior  Flags="ValidateOnUnfocusing"/>
                                </xct:MultiValidationBehavior>
                            </Entry.Behaviors>
                        </Entry>

并有一个按钮：

     <Button Text="Send" Command="{Binding LoadSendRegistrationCommand}" TextColor="#07987f"  BackgroundColor="#eeeeee"  Margin="0,10,0,10"></Button>

当单击按钮时，如果电子邮件无效，如何检查和返回消息？