[英]Xamarin.Forms Animation for multiple controls in parallel
For my Xamarin.Forms project I need to animate two Xamarin Frame items in parallel, but I just don't understand the example where they use:对于我的 Xamarin.Forms 项目,我需要同时为两个 Xamarin Frame 项目设置动画,但我只是不明白它们使用的示例:
async void OnAnimateLabelButtonClicked(object sender, EventArgs e)
{
...
await Task.WhenAll(
label.ColorTo(Color.Red, Color.Blue, c => label.TextColor = c, 5000),
label.ColorTo(Color.Blue, Color.Red, c => label.BackgroundColor = c, 5000));
...
}
Task.WhenAll
which - in my humble opinion - does not guarantee that it runs on the GUI main thread, as no Device.BeginInvokeOnMainThread()
is to be seen. Task.WhenAll
- 在我看来 - 并不能保证它在 GUI 主线程上运行,因为没有Device.BeginInvokeOnMainThread()
是可见的。
According to this forums.xamarin.com entry, the preferred way to use multiple animations at a time is via:根据此forums.xamarin.com条目,一次使用多个动画的首选方法是通过:
Animation a = new Animation();
a.Add(0, 1, new Animation(f => this.GuidanceLabel.Opacity = f, 1, 0, Easing.SinInOut, null));
a.Add(0, 1, new Animation(f => this.EnableAccess.Opacity = f, 1, 0, Easing.SinOut, null));
a.Commit(
owner:this.GuidanceLabel,
name:"DoubleFader",
length:400,
finished:(x, y) =>
{
this.SetPhotoAccessDeniedState();
this.GuidanceLabel.FadeTo(1, 400, Easing.CubicIn);
});
So, I suppose, I have to wrap my animation in a Device.BeginInvokeOnMainThread()
to make it work properly, and for my special animation case, the workflow would be:所以,我想,我必须将我的动画包装在
Device.BeginInvokeOnMainThread()
才能使其正常工作,对于我的特殊动画情况,工作流程是:
Frame1.TranslateYto (-90, duration1);
Frame1.Content.IsVisible = true; // Was formerly false
Frame1.TranslateYto (0, duration2);
And for Frame2 the same in parallel.而对于Frame2也是一样的并行。
So I have tried:所以我试过:
Device.BeginInvokeOnMainThread(() =>
{
Animation a = new Animation();
a.Add(0, 1, new Animation(v => frame1.RotationY = v, 0, -90));
a.Add(0, 1, new Animation(v => frame2.RotationY = v, 0, -90));
a.Commit(
owner: frame1,
name: "flip1",
length: 50,
finished: (x, y) =>
{
frame1.Content.IsVisible = false;
frame2.Content.IsVisible = false;
});
a = new Animation();
a.Add(0, 1, new Animation(v => frame1.RotationY = v, -90, 0));
a.Add(0, 1, new Animation(v => frame2.RotationY = v, -90, 0));
a.Commit(
owner: frame1,
name: "flip2",
length: 250);
});
But it crashes with a NullReferenceExecption ...但它崩溃了NullReferenceExecption ...
Maybe someone can shed some more light on the problem?也许有人可以对这个问题有更多的了解?
I add two Frame control in window and create same animation as you, but I don't have any issue.我在窗口中添加了两个 Frame 控件并创建了与您相同的动画,但我没有任何问题。 Here is my code.
这是我的代码。
<StackLayout>
<Frame
x:Name="frame1"
HorizontalOptions="CenterAndExpand"
VerticalOptions="FillAndExpand">
<Label
HorizontalOptions="CenterAndExpand"
Text="this is test!!!!!!!"
VerticalOptions="CenterAndExpand" />
</Frame>
<Frame x:Name="frame2" HorizontalOptions="CenterAndExpand" VerticalOptions="EndAndExpand">
<Label
HorizontalOptions="CenterAndExpand"
Text="this is test22222222222222!!!!!!!"
VerticalOptions="CenterAndExpand" />
</Frame>
<Button
x:Name="btn1"
Clicked="btn1_Clicked"
HeightRequest="50"
Text="btn1"
WidthRequest="300" />
</StackLayout>
private void btn1_Clicked(object sender, EventArgs e)
{
Device.BeginInvokeOnMainThread(() => {
Animation a = new Animation();
a.Add(0, 1, new Animation(v => frame1.RotationY = v, 0, -90));
a.Add(0, 1, new Animation(v => frame2.RotationY = v, 0, -90));
a.Commit(
owner: frame1,
name: "flip1",
length: 50,
finished: (x, y) =>
{
frame1.Content.IsVisible = false;
frame2.Content.IsVisible = false;
});
a = new Animation();
a.Add(0, 1, new Animation(v => frame1.RotationY = v, -90, 0));
a.Add(0, 1, new Animation(v => frame2.RotationY = v, -90, 0));
a.Commit(
owner: frame1,
name: "flip2",
length: 250);
});
}
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