Manipulating the opacity of an object (control)

Question

Manipulating the opacity of an object (control)

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#1 by (4 votes)

2

Example: When I press a button, I will display a painel by editing only its visibility, it works, but it has no effect,

Then I had the idea of pressing the button to display the panel with opacity 0 and then increasing it gradually. But since the smartphone processor is fast and you can not see the effect, then I thought to deploy a sleep , the result was that pressing the button takes about 2 seconds to display the panel, but displays it dry, without transition. sleep only slowed the button.

Code:

private void Button_Click(object sender, RoutedEventArgs e)
{ // Ao apertar o botão
    if (painel.Visibility == System.Windows.Visibility.Visible)
    { //olha se o painel já está visivel
        int cont = 200;
        while (cont > 0)
        { // vai decrementando, e diminuindo sua opacidade
            painel.Opacity = cont * 0.5;
            System.Threading.Thread.Sleep(2); //tentativa de retardar um pouco
            if (cont == 1) // quando a opacidade for 1 eu irei ocultar o painel
                painel.Visibility = System.Windows.Visibility.Collapsed;
            cont -= 1;
        }
    }  
    else
    { // se ao apertao do botão ele estiver oculto
        int cont = 0;
        painel.Visibility = System.Windows.Visibility.Visible; //torna ele visível
        painel.Opacity = 0; // deixa com opacidade 0
        while (cont < 100)
        { //vai aumentando a opacidade ate ela ser 99 
            painel.Opacity = cont * 0.5;
            System.Threading.Thread.Sleep(2); / tentatida de retardar
            cont += 1;
        }
    }     
}

As I said, with sleep , when I press the button it waits for 2 seconds and displays the panel without going controlling the opacity, it only displays it, without 'transition'. I'm deploying this in an app, where painel is StackPanel . It's an app for Windows Phone 8.1 with Silverlight.

c# windows-phone

asked by anonymous 23.08.2015 / 17:33

1 answer

Jquery get the first and second tag inside a div JavaScript does not recognize number 10

score 4 · Accepted Answer

Well, with the help of @ramaral it looks like this:

page .xaml, panel part

<!-- Uma 'div'. -->
<StackPanel Grid.Row="1">

    <StackPanel.Resources>
        <!-- Animação para ocultar o painel -->
        <Storyboard x:Name="ocultar">
            <!-- Uma animação Double, pois opacidade pe float, determino aqui onde vou aplicar,
             quando começa, quando termina e gero um método para quando ele é completada. -->
            <DoubleAnimation Completed="DoubleAnimation_Completed"
                Storyboard.TargetName="painel"
                Storyboard.TargetProperty="Opacity"
                From="1.0" To="0.0"  Duration="0:0:1" />
        </Storyboard>

        <!-- Animação para mostrar o painel -->
        <Storyboard x:Name="mostrar">
        <!-- Mesma coida do anterior, mas aqui estou aumentando a opacidade, e não tenho método
        de complete, pois torno o painel visível antes de executar a animação -->
            <DoubleAnimation x:Name="aMostrar" 
            Storyboard.TargetName="painel"
            Storyboard.TargetProperty="Opacity"
            From="0.0" To="1.0" Duration="0:0:1" />
        </Storyboard>
    </StackPanel.Resources>

    <!-- Painel -->
    <StackPanel Grid.Row="1" Height="700" Name="painel" Background="Crimson"  HorizontalAlignment="Left" VerticalAlignment="Top" Margin="0,0,0,0" Width="400"/>
</StackPanel>

.cs

private void Button_Click(object sender, RoutedEventArgs e)
{ // Ao pressionar do botão
    if (painel.Visibility == System.Windows.Visibility.Visible)
    { //se o painel estiver visivel ele chama a animação p/ ocultar
        ocultar.Begin();
    }  
    else
    { //se o painel estiver oculto, ele torna visivel e chama a animação de mostrar
        painel.Visibility = System.Windows.Visibility.Visible;
        mostrar.Begin();
    }     
}

private void DoubleAnimation_Completed(object sender, EventArgs e)
{ //metodo chamado quando a anicação de ocultar termina, ele apenas deixa o painel oculto
    painel.Visibility = System.Windows.Visibility.Collapsed;
}