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。