我想在暂停/播放模式下分别在视频上显示播放/暂停图标。几秒钟后,图标应该消失。将淡出/淡淡的动画应用于它的最佳方法是什么?
<MediaElement Name="videoMediaElement" AreTransportControlsEnabled="True" Stretch="Fill" PointerPressed="videoMediaElement_PointerPressed" MediaOpened="videoMediaElement_MediaOpened" CurrentStateChanged="Media_State_Changed" >
<MediaElement.TransportControls>
<MediaTransportControls Background="Red" Foreground="White" IsStopButtonVisible="True" IsStopEnabled="True" IsTextScaleFactorEnabled="True" IsPlaybackRateEnabled="True" IsPlaybackRateButtonVisible="True" IsFastForwardButtonVisible="True" IsFastForwardEnabled="True" IsFastRewindButtonVisible="True" IsFastRewindEnabled="True" />
</MediaElement.TransportControls>
</MediaElement>
<Image x:Name="icon_play" Source="Assets/icon_play.png" Visibility="Collapsed" Opacity="0.5" HorizontalAlignment="Center" Height="100px" Width="100"/>
<Image x:Name="icon_pause" Source="Assets/icon_pause.png" Visibility="Collapsed" Opacity="0.5" HorizontalAlignment="Center" Height="100px" Width="100"/>
private void Media_State_Changed(object sender, RoutedEventArgs args)
{
if (videoMediaElement.CurrentState == MediaElementState.Paused)
{
icon_play.Visibility = Visibility.Visible;
icon_pause.Visibility = Visibility.Collapsed;
}
else if (videoMediaElement.CurrentState == MediaElementState.Playing)
{
icon_pause.Visibility = Visibility.Visible;
icon_play.Visibility = Visibility.Collapsed;
}
}
通过设置AreTransportControlsEnabled="True"
,您决定使用内置媒体播放器。您可以进行一些自定义(例如颜色),但是这些非常有限。如果要构建自己的UI,则需要设置AreTransportControlsEnabled="False"
并使用XAML创建自己的UI。
创建XAML动画类似:
<Storyboard x:Name="FadeOut" Target="icon_play" TargetProperty="Opacity">
<DoubleAnimation To="0" Duration="0:0:0.3"/>
</Storyboard>
,只需致电FadeOut.Begin();
或创建(我更喜欢它)组成动画:
var compositor = ElementCompositionPreview.GetElementVisual(this).Compositor;
var implicitOpacity = compositor.CreateScalarKeyFrameAnimation();
implicitOpacity.Target = "Opacity";
implicitOpacity.InsertExpressionKeyFrame(1, "This.FinalValue");
implicitOpacity.Duration = TimeSpan.FromMilliseconds(300);
var implicitCollection = compositor.CreateImplicitAnimationCollection();
implicitCollection["Opacity"] = implicitOpacity;
var playVisual = ElementCompositionPreview.GetElementVisual(play_icon);
playVisual.ImplicitAnimations = implicitCollection;
现在,每次您更改Visual的不透明度值时 - 它将被动画:playVisual.Opacity = 0;