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功能块动画

您可以通过几种不同的方式为功能块添加动画效果，包括以下方式：

使用补间动画的清除过渡效果。
平滑的淡出淡入和滑动动画效果（适用于进入和退出功能块）。

显示清除过渡效果

若要显示两个值之间的平滑清除效果，您可以为元素启用补间动画，如以下代码段所示：

Kotlin

private val defaultValue = 0f
private var startValue = 15f
private var endValue = 105f
private val animationDurationInMillis = 2000f // 2 seconds

override fun onTileRequest(requestParams: TileRequest) =
    Futures.immediateFuture(
        // Add timeline and layout containers. CircularProgressIndicator is an
        // inner element of those containers.
        CircularProgressIndicator.Builder()
            .setProgress(
                FloatProp.Builder(/* static value */ 0.25f)
                    .setDynamicValue(
                    // Or you can use some other dynamic object, for example
                    // from the platform and then at the end of expression
                    // add animate().
                        DynamicFloat.animate(startValue, endValue,
                            AnimationSpec.Builder()
                                .setAnimationParameters(
                                    AnimationParameters.Builder()
                                        .setDurationMillis(animationDurationInMillis)
                                        .build()
                                ).build()
                        )
                    ).build()
            ).build()
        // Finish building all elements that contain CircularProgressIndicator.
    )

Java

private float defaultValue = 0f;
private float startValue = 15f;
private float endValue = 105f;
private float animationDurationInMillis = 2000f; // 2 seconds

@Override
protected ListenableFuture<Tile> onTileRequest(
       @NonNull TileRequest requestParams
) {
    return Futures.immediateFuture(
        // Add timeline and layout containers. CircularProgressIndicator is an
        // inner element of those containers.
        new CircularProgressIndicator.Builder()
            .setProgress(
                new FloatProp.Builder(/* static value */ 0.25f)
                    .setDynamicValue(
                    // Or you can use some other dynamic object, for example
                    // from the platform and then at the end of expression
                    // add animate().
                        DynamicFloat.animate(startValue, endValue,
                            new AnimationSpec.Builder()
                                .setAnimationParameters(
                                    new AnimationParameters.Builder()
                                        .setDurationMillis(animationDurationInMillis)
                                        .build()
                                ).build()
                        )
                    ).build()
            ).build()
        // Finish building all elements that contain CircularProgressIndicator.
    );
}

设置弧形方向

如果功能块包含弧线，您可能不希望弧线或文本始终显示会按照用户所选语言的默认文本方向逐渐增大。要指定弧形增长方向，请使用 ArcDirection API：

Kotlin

@OptIn(ProtoLayoutExperimental::class)
public override fun onTileRequest(
        requestParams: RequestBuilders.TileRequest
): ListenableFuture<Tile> {
    return Futures.immediateFuture(Tile.Builder()
        .setResourcesVersion(RESOURCES_VERSION)
        .setTileTimeline(Timeline.fromLayoutElement(
            EdgeContentLayout.Builder(deviceParameters)
                .setEdgeContent(
                    Arc.Builder()
                        // Arc should always grow clockwise.
                        .setArcDirection(LayoutElementBuilders.ARC_DIRECTION_CLOCKWISE)
                        .addContent(
                            ArcLine.Builder()
                            // Set color, length, thickness, and more.
                            // Arc should always grow clockwise.
                            .setArcDirection(
                                LayoutElementBuilders.ARC_DIRECTION_CLOCKWISE)
                            .build()
                        ).build()
                ).build())
        ).build()
    )
}

Java

@OptIn(markerClass = ProtoLayoutExperimental.class)
@NonNull
@Override
protected ListenableFuture<Tile> onTileRequest(
        @NonNull RequestBuilders.TileRequest requestParams
) {
    return Futures.immediateFuture(new Tile.Builder()
        .setResourcesVersion(RESOURCES_VERSION)
        .setTileTimeline(Timeline.fromLayoutElement(
            new EdgeContentLayout.Builder(deviceParameters)
                .setEdgeContent(
                    new Arc.Builder()
                        // Arc should always grow clockwise.
                        .setArcDirection(LayoutElementBuilders.ARC_DIRECTION_CLOCKWISE)
                        .addContent(
                            new ArcLine.Builder()
                            // Set color, length, thickness, and more.
                            // Arc should always grow clockwise.
                            .setArcDirection(
                                LayoutElementBuilders.ARC_DIRECTION_CLOCKWISE)
                            .build())
                        .build())
                .build()))
        .build()
    );
}

显示平滑的淡出淡入或滑动效果

为了更清楚地指明元素在功能块中出现或消失的动作，或者更精细地显示在功能块中分步变化的值，请在功能块动画中使用淡入淡出和滑动效果。

如果功能块布局包含值会发生变化的元素，功能块会显示该元素的退出动画，然后更新布局并显示该元素的进入动画。

淡出淡入过渡

以下代码段演示了如何使用 DefaultContentTransitions 中的辅助方法执行淡入和淡出过渡。如需定义自定义的 FadeInTransition 和 FadeOutTransition 对象，请在过渡 setter 方法中分别调用 setFadeIn() 和 setFadeOut()。

Kotlin

@OptIn(ProtoLayoutExperimental::class)
public override fun onTileRequest(
        requestParams: RequestBuilders.TileRequest
): ListenableFuture<Tile> {
    // Assumes that you've defined a custom helper method called
    // getTileTextToShow().
    val tileText = getTileTextToShow()
    return Futures.immediateFuture(Tile.Builder()
        .setResourcesVersion(RESOURCES_VERSION)
        .setTileTimeline(Timeline.fromLayoutElement(
            Text.Builder(this, tileText)
                .setModifiers(
                    ModifiersBuilders.Modifiers.Builder()
                        .setContentUpdateAnimation(AnimatedVisibility.Builder()
                            .setEnterTransition(
                                    DefaultContentTransitions.fadeIn())
                            .setExitTransition(
                                    DefaultContentTransitions.fadeOut()
                            ).build())
                ).build())
        ).build()
    )
}

Java

@OptIn(markerClass = ProtoLayoutExperimental.class)
@NonNull
@Override
protected ListenableFuture<Tile> onTileRequest(
        @NonNull RequestBuilders.TileRequest requestParams
) {
    // Assumes that you've defined a custom helper method called
    // getTileTextToShow().
    String tileText = getTileTextToShow();

    return Futures.immediateFuture(new Tile.Builder()
        .setResourcesVersion(RESOURCES_VERSION)
        .setTileTimeline(Timeline.fromLayoutElement(
            new Text.Builder(this, tileText)
                .setModifiers(
                    new ModifiersBuilders.Modifiers.Builder()
                        .setContentUpdateAnimation(new AnimatedVisibility.Builder()
                            .setEnterTransition(
                                    DefaultContentTransitions.fadeIn())
                            .setExitTransition(
                                    DefaultContentTransitions.fadeOut())
                            .build())
                .build()))
        .build()
    );
}

滑动过渡

另一个代码段演示了如何使用 DefaultContentTransitions 中的辅助方法执行滑入和滑出过渡。您还可以通过在过渡 setter 方法中分别调用 setSlideIn() 和 setSlideOut() 来定义自定义的 SlideInTransition 和 SlideOutTransition 对象。

Kotlin

@OptIn(ProtoLayoutExperimental::class)
public override fun onTileRequest(
    requestParams: RequestBuilders.TileRequest
): ListenableFuture<Tile> {
    // Assumes that you've defined a custom helper method called
    // getTileTextToShow().
    val tileText = getTileTextToShow()
    return Futures.immediateFuture(Tile.Builder()
        .setResourcesVersion(RESOURCES_VERSION)
        .setTileTimeline(Timeline.fromLayoutElement(
            Text.Builder(this, tileText)
                .setModifiers(
                    Modifiers.Builder()
                         .setContentUpdateAnimation(AnimatedVisibility.Builder()
                            .setEnterTransition(
                                DefaultContentTransitions.slideIn(
                                    SLIDE_DIRECTION_LEFT_TO_RIGHT)
                            ).setExitTransition(
                                DefaultContentTransitions.slideOut(
                                    SLIDE_DIRECTION_LEFT_TO_RIGHT)
                            ).build()
                        ).build()
                ).build()
        )).build()
    )
}

Java

@OptIn(markerClass = ProtoLayoutExperimental.class)
@NonNull
@Override
protected ListenableFuture<Tile> onTileRequest(
        @NonNull RequestBuilders.TileRequest requestParams
) {
    // Assumes that you've defined a custom helper method called
    // getTileTextToShow().
    String tileText = getTileTextToShow();
    return Futures.immediateFuture(Tile.Builder()
        .setResourcesVersion(RESOURCES_VERSION)
        .setTileTimeline(Timeline.fromLayoutElement(
            new Text.Builder(this, tileText)
                .setModifiers(
                    new Modifiers.Builder()
                        .setContentUpdateAnimation(
                            new AnimatedVisibility.Builder()
                                .setEnterTransition(
                                    DefaultContentTransitions.slideIn(
                                        SLIDE_DIRECTION_LEFT_TO_RIGHT))
                                .setExitTransition(
                                    DefaultContentTransitions.slideOut(
                                        SLIDE_DIRECTION_LEFT_TO_RIGHT))
                                .build())
                        .build())
                .build()))
        .build()
    );
}

显示转换

为了吸引用户注意功能块中的特定元素或区域，您可以以及旋转、缩放和平移等各种类型的转换。

与转换相关的许多浮点值都接受动态表达式，可让您为这些转换添加动画效果。

旋转

要围绕可自定义的轴心点执行顺时针旋转，请使用代码类似于以下内容：

Kotlin

// Last line in your onTileRequest() method implementation.
return Futures.immediateFuture(Tile.Builder()
    .setResourcesVersion(RESOURCES_VERSION)
    .setTileTimeline(Timeline.fromLayoutElement(
        Text.Builder(this, someTileText)
            .setModifiers(
                    ModifiersBuilders.Transformation.Builder()
                        // Set the pivot point 50 dp from the left edge
                        // and 100 dp from the top edge of the screen.
                        .setPivotX(dp(50))
                        .setPivotY(dp(100))
                        // Rotate the element 45 degrees clockwise.
                        .setRotation(
                            degrees(45f)
                        ).build()
            ).build())
    ).build()
)

Java

// Last line in your onTileRequest() method implementation.
return Futres.immediateFuture(new Tile.Builder()
    .setResourcesVersion(RESOURCES_VERSION)
    .setTileTimeline(Timeline.fromLayoutElement(
        new Text.Builder(this, someTileText)
            .setModifiers(
                    new ModifiersBuilders.Transformation.Builder()
                        // Set the pivot point 50 dp from the left edge
                        // and 100 dp from the top edge of the screen.
                        .setPivotX(dp(50))
                        .setPivotY(dp(100))
                        // Rotate the element 45 degrees clockwise.
                        .setRotation(
                            degrees(45f))
                        .build())
            .build()))
    .build()
);

扩缩

要按水平和垂直缩放比例放大或缩小元素，请使用代码类似于以下内容：

Kotlin

// Last line in your onTileRequest() method implementation.
return Futures.immediateFuture(Tile.Builder()
    .setResourcesVersion(RESOURCES_VERSION)
    .setTileTimeline(Timeline.fromLayoutElement(
        Text.Builder(this, someTileText)
            .setModifiers(
                    ModifiersBuilders.Transformation.Builder()
                        // Set the pivot point 50 dp from the left edge
                        // and 100 dp from the top edge of the screen.
                        .setPivotX(dp(50))
                        .setPivotY(dp(100))
                        // Shrink the element by a scale factor
                        // of 0.5 horizontally and 0.75 vertically.
                        .setScaleX(TypeBuilders.FloatProp.Builder(0.5f)
                                .build())
                        .setScaleY(TypeBuilders.FloatProp.Builder(0.75f)
                                .build()
                        ).build()
            ).build())
    ).build()
)

Java

// Last line in your onTileRequest() method implementation.
return Futres.immediateFuture(new Tile.Builder()
    .setResourcesVersion(RESOURCES_VERSION)
    .setTileTimeline(Timeline.fromLayoutElement(
        new Text.Builder(this, someTileText)
            .setModifiers(
                    new ModifiersBuilders.Transformation.Builder()
                        // Set the pivot point 50 dp from the left edge
                        // and 100 dp from the top edge of the screen.
                        .setPivotX(dp(50))
                        .setPivotY(dp(100))
                        // Shrink the element by a scale factor
                        // of 0.5 horizontally and 0.75 vertically.
                        .setScaleX(new TypeBuilders.FloatProp.Builder(0.5f)
                                .build())
                        .setScaleY(new TypeBuilders.FloatProp.Builder(0.75f)
                                .build())
                        .build())
            .build()))
    .build()
);

几何平移

在屏幕上按特定数量的密度像素 (dp) 移动元素水平或垂直方向，请使用类似于以下内容的代码：

Kotlin

// Last line in your onTileRequest() method implementation.
return Futures.immediateFuture(Tile.Builder()
    .setResourcesVersion(RESOURCES_VERSION)
    .setTileTimeline(Timeline.fromLayoutElement(
        Text.Builder(this, someTileText)
            .setModifiers(
                    ModifiersBuilders.Transformation.Builder()
                        // Translate (move) the element 60 dp to the right
                        // and 80 dp down.
                        .setTranslationX(dp(60))
                        .setTranslationY(dp(80))
                        .build()
            ).build())
    ).build()
)

Java

// Last line in your onTileRequest() method implementation.
return Futres.immediateFuture(new Tile.Builder()
    .setResourcesVersion(RESOURCES_VERSION)
    .setTileTimeline(Timeline.fromLayoutElement(
        new Text.Builder(this, someTileText)
            .setModifiers(
                    new ModifiersBuilders.Transformation.Builder()
                        // Translate (move) the element 60 dp to the right
                        // and 80 dp down.
                        .setTranslationX(dp(60))
                        .setTranslationY(dp(80))
                        .build())
            .build()))
    .build()
);

不要在动画播放过程中显示重要信息

以下列举几种会停用动画的情况：

系统的功能块渲染程序可能会停用所有功能块的动画。
一个功能块一次只能为 4 个元素添加动画效果。如果您尝试同时为超过 4 个元素添加动画效果，其中有些元素会无法显示动画。

如果动画已停用，相应元素就会处于静态，并显示动画的结束值。因此，请勿依赖动画的行为（例如持续时间）来显示重要信息。