【鸿蒙】HarMonyOS的自定义组件之抽奖大转盘

1. 介绍

当系统提供的组件无法满足设计需求时，您可以创建自定义组件，根据设计需求自定义组件的属性及响应事件，并绘制组件。自定义组件是在组件预留的两个自定义图层中实现绘制，通过addDrawTask方法添加绘制任务，最终与组件的其它图层合成在一起呈现在界面中。

实现思路：

创建自定义组件的类，并继承Component或其子类，添加构造方法。
实现Component.DrawTask接口，在onDraw方法中进行绘制。
根据自定义组件需要完成的功能，去选择实现相应的接口。例如可实现Component.EstimateSizeListener响应测量事件、Component.TouchEventListener响应触摸事件、Component.ClickedListener响应点击事件、Component.LongClickedListener响应长按事件、Component.DoubleClickedListener响应双击事件等。
本教程实现圆形抽奖转盘功能，要实现如下接口：

a) 需要实现获取屏幕宽高度、中心点坐标，所以实现Component.EstimateSizeListener接口，重写onEstimateSize方法。

b) 需要实现点击中心圆盘区域位置开始抽奖功能，所以实现Component.TouchEventListener，重写onTouchEvent方法。

2. 搭建HarmonyOS环境

我们首先需要完成HarmonyOS开发环境搭建，可参照如下步骤进行。

安装DevEco Studio，详情请参考下载和安装软件。
设置DevEco Studio开发环境，DevEco Studio开发环境依赖于网络环境，需要连接上网络才能确保工具的正常使用，可以根据如下两种情况来配置开发环境：
1. 如果可以直接访问Internet，只需进行下载HarmonyOS SDK操作。
2. 如果网络不能直接访问Internet，需要通过代理服务器才可以访问，请参考配置开发环境。

3. 基本步骤

创建自定义组件的类，并继承Component或其子类，添加构造方法。

public class LuckyCirclePanComponent extends Component implements Component.DrawTask, 
	Component.EstimateSizeListener, Component.TouchEventListener { 
	public LuckyCirclePanComponent(Context context) { 
		super(context); 
		this.context = context; 
		// 初始化画笔 
		initPaint(); 
		// 获取屏幕的宽高度、中心点坐标，调用onEstimateSize方法 
		setEstimateSizeListener(this); 
		// 添加绘制任务，调用onDraw方法 
		addDrawTask(this); 
		// 实现点击中心圆盘区域位置开始抽奖功能，调用onTouchEvent方法 
		setTouchEventListener(this); 
	} 
}

实现Component.DrawTask接口，在onDraw方法中进行绘制。

@Override 
public void onDraw(Component component, Canvas canvas) { 
	// 将画布沿X、Y轴平移指定距离 
	canvas.translate(centerX, centerY); 
	// 画外部圆盘的花瓣 
	drawFlower(canvas); 
	// 画外部圆盘、小圈圈、五角星 
	drawOutCircleAndFive(canvas); 
	// 画内部扇形抽奖区域 
	drawInnerArc(canvas); 
	// 画内部扇形区域文字 
	drawArcText(canvas); 
	// 画内部扇形区域奖品对应的图片 
	drawImage(canvas); 
	// 画中心圆盘和指针 
	drawCenter(canvas); 
}

4. 获取屏幕大小、中心点

实现Component.EstimateSizeListener接口，重写onEstimateSize方法，获取屏幕的宽高度width、height及中心点坐标centerX、centerY。

@Override 
public boolean onEstimateSize(int widthEstimateConfig, int heightEstimateConfig) { 
        int componentWidth = EstimateSpec.getSize(widthEstimateConfig); 
        int componentHeight = EstimateSpec.getSize(heightEstimateConfig); 
        this.width = componentWidth; 
        this.height = componentHeight; 
        centerX = this.width / TWO; 
        centerY = this.height / TWO; 
        setEstimatedSize( 
        
        EstimateSpec.getChildSizeWithMode(componentWidth, componentWidth, EstimateSpec.PRECISE), 
        
        EstimateSpec.getChildSizeWithMode(componentHeight, componentHeight, EstimateSpec.PRECISE) 
        ); 
        return true; 
}

5. 画外部圆盘

画外部圆盘的花瓣：通过调用Canvas的rotate()方法，将画布旋转指定角度。通过调用Canvas的save()和restore()方法，使画布保存最新的绘制状态。根据想要绘制的花瓣个数，改变旋转角度，循环画出花瓣效果。

private void drawFlower(Canvas canvas) { 
	float beginAngle = startAngle + avgAngle; 
	float radius = centerX - padding; 
	for (int i = 0; i < COUNT; i++) { 
		canvas.save(); 
		canvas.rotate(beginAngle, 0F, 0F); 
		paintFlower.setColor(ColorUtils.PAINT_FLOWER_YELLOW); 
		canvas.drawCircle(-radius / TWO, radius / TWO, radius / TWO, paintFlower); 
 
		paintFlower.setColor(ColorUtils.PAINT_FLOWER_PINK); 
		canvas.drawCircle(-radius / TWO, radius / TWO, (radius - padding) / TWO, paintFlower); 
		beginAngle += avgAngle; 
		canvas.restore(); 
	} 
}

2.画外部圆盘：在指定的X、Y（0F, 0F）坐标处，画一个半径为centerX - padding的圆形（其实就是绘制一个红色的圆盘）。

paintOutCircle.setColor(ColorUtils.PAINT_OUT_CIRCLE); 
canvas.drawCircle(0F, 0F, centerX - padding, paintOutCircle);

3.画外部圆盘边上的小圈圈和五角星：接下来一个for循环，且角度每次递增(avgAngle / THREE)，就是绘制圆环上的小圈圈和五角星了。因为是交替绘制五角星和小圈圈，所以用一个条件判断语句去绘制。

float beginAngle = startAngle + avgAngle / THREE; 
for (int i = 0; i < COUNT * THREE; i++) { 
	canvas.save(); 
	canvas.rotate(beginAngle, 0F, 0F); 
	if (0 == i % TWO) { 
		paintOutCircle.setColor(Color.WHITE); 
		canvas.drawCircle(centerX - padding - padding / TWO, 0F, vp2px(FIVE), paintOutCircle); 
	} else { 
		paintFiveStart(canvas); 
	} 
	beginAngle += avgAngle / THREE; 
	canvas.restore(); 
}

4.画五角星：通过计算获取到五角星的5个顶点位置（计算依据：五角星每个角的角度为36°，然后根据三角函数即可算出各个点的坐标），再使用Canvas、Path、Paint将5个顶点通过画线连接在一起，就完成了五角星的绘制。

private void paintFiveStart(Canvas canvas) { 
	// 画五角星的path 
	Path path = new Path(); 
	float[] points = fivePoints(centerX - padding - padding / TWO, 0F, padding); 
	for (int i = 0; i < points.length - 1; i = i + TWO) { 
		path.lineTo(points[i], points[i + 1]); 
	} 
	path.close(); 
	canvas.drawPath(path, paintFive); 
}
/** 
 * fivePoints 获取五角星的五个顶点 
 * 
 * @param pointXa 起始点A的x轴绝对位置 
 * @param pointYa 起始点A的y轴绝对位置 
 * @param sideLength 五角星的边长 
 * @return 五角星5个顶点坐标 
 */ 
private static float[] fivePoints(float pointXa, float pointYa, float sideLength) { 
	final int eighteen = 18; 
	float pointXb = pointXa + sideLength / TWO; 
	double num = sideLength * Math.sin(Math.toRadians(eighteen)); 
	float pointXc = (float) (pointXa + num); 
	float pointXd = (float) (pointXa - num); 
	float pointXe = pointXa - sideLength / TWO; 
	float pointYb = (float) (pointYa + Math.sqrt(Math.pow(pointXc - pointXd, TWO) 
			- Math.pow(sideLength / TWO, TWO))); 
	float pointYc = (float) (pointYa + Math.cos(Math.toRadians(eighteen)) * sideLength); 
	float pointYd = pointYc; 
	float pointYe = pointYb; 
	float[] points = new float[]{pointXa, pointYa, pointXd, pointYd, pointXb, pointYb, 
		pointXe, pointYe, pointXc, pointYc, pointXa, pointYa}; 
	return points; 
}

6. 画内部扇形抽奖区域

画抽奖区域扇形：使用RectFloat和Arc对象绘制弧，rect表示圆弧包围矩形的左上角和右下角的坐标，参数new Arc(startAngle, avgAngle, true)表示圆弧参数，例如起始角度、后掠角以及是否从圆弧的两个端点到其中心绘制直线。

private void drawInnerArc(Canvas canvas) { 
	float radius = Math.min(centerX, centerY) - padding * TWO; 
	RectFloat rect = new RectFloat(-radius, -radius, radius, radius); 
	for (int i = 0; i < COUNT; i++) { 
		paintInnerArc.setColor(colors[i]); 
		canvas.drawArc(rect, new Arc(startAngle, avgAngle, true), paintInnerArc); 
		startAngle += avgAngle; 
	} 
}

2.画抽奖区域文字：利用Path，创建绘制路径，添加Arc，然后设置水平和垂直的偏移量。垂直偏移量radius / FIVE就是当前Arc朝着圆心移动的距离；水平偏移量，就是顺时针去旋转，水平偏移(Math.sin(avgAngle / CIRCLE * Math.PI) * radius) - measureWidth / TWO，是为了让文字在当前弧范围文字居中。最后，用path去绘制文本。

private void drawArcText(Canvas canvas) { 
	for (int i = 0; i < COUNT; i++) { 
		// 创建绘制路径 
		Path circlePath = new Path(); 
		float radius = Math.min(centerX, centerY) - padding * TWO; 
		RectFloat rect = new RectFloat(-radius, -radius, radius, radius); 
		circlePath.addArc(rect, startAngle, avgAngle); 
		float measureWidth = paintArcText.measureText(textArrs[i]); 
		// 偏移量 
		float advance = (float) ((Math.sin(avgAngle / CIRCLE * Math.PI) * radius) - measureWidth / TWO); 
		canvas.drawTextOnPath(paintArcText, textArrs[i], circlePath, advance, radius / FIVE); 
		startAngle += avgAngle; 
	} 
}

3.画抽奖区域文字对应图片：pixelMaps表示文字对应的图片ResourceId转换成PixelMap的数组，pixelMapHolderList表示将PixelMap转换成PixelMapHolder图片List，dst表示PixelMapHolder对象的左上角（ -imageHeight / TWO，imageHeight / TWO）和右下角（centerX / THREE + imageWidth，centerX / THREE）的坐标。

private void drawImage(Canvas canvas) { 
	float beginAngle = startAngle + avgAngle / TWO; 
	for (int i = 0; i < COUNT; i++) { 
		int imageWidth = pixelMaps[i].getImageInfo().size.width; 
		int imageHeight = pixelMaps[i].getImageInfo().size.height; 
		canvas.save(); 
		canvas.rotate(beginAngle, 0F, 0F); 
		// 指定图片在屏幕上显示的区域 
		RectFloat dst = new RectFloat(centerX / THREE, -imageHeight / TWO, 
				centerX / THREE + imageWidth, imageHeight / TWO); 
		canvas.drawPixelMapHolderRect(pixelMapHolderList.get(i), dst, paintImage); 
		beginAngle += avgAngle; 
		canvas.restore(); 
	} 
}

7. 画中心圆盘和指针

画中心圆盘大指针：通过Path ，确定要移动的三个点的坐标(-centerX / nine, 0F)、(centerX / nine, 0F)、(0F, -centerX / THREE)，去绘制指针。

Path path = new Path(); 
path.moveTo(-centerX / nine, 0F); 
path.lineTo(centerX / nine, 0F); 
path.lineTo(0F, -centerX / THREE); 
path.close(); 
canvas.drawPath(path, paintPointer);

2.画内部大圆和小圆：在圆盘圆心处，绘制两个半径分别为centerX / seven + padding / TWO、centerX / seven的中心圆盘。

// 画内部大圆 
paintCenterCircle.setColor(ColorUtils.PAINT_POINTER); 
canvas.drawCircle(0F, 0F, centerX / seven + padding / TWO, paintCenterCircle); 
// 画内部小圆 
paintCenterCircle.setColor(Color.WHITE); 
canvas.drawCircle(0F, 0F, centerX / seven, paintCenterCircle);

3.画中心圆盘小指针：与步骤1中画中心圆盘大指针类似，通过Path去绘制中心圆盘小指针。

Path smallPath = new Path(); 
smallPath.moveTo(-centerX / eighteen, 0F); 
smallPath.lineTo(centerX / eighteen, 0F); 
smallPath.lineTo(0F, -centerX / THREE + padding / TWO); 
smallPath.close(); 
canvas.drawPath(smallPath, paintSmallPoint);

4.画中心圆弧文字：通过Paint的getFontMetrics()方法，获取绘制字体的建议行距，然后根据建议行距去绘制文本。

Paint.FontMetrics fontMetrics = paintCenterText.getFontMetrics(); 
float textHeight = (float) Math.ceil(fontMetrics.leading - fontMetrics.ascent); 
canvas.drawText(paintCenterText, "开始", 0F, textHeight / THREE);

8. 实现抽奖功能

实现Component.TouchEventListener接口，重写onTouchEvent方法，获取屏幕上点击的坐标，当点击的范围在中心圆盘区域时，圆形转盘开始转动抽奖。

@Override 
public boolean onTouchEvent(Component component, TouchEvent touchEvent) { 
	final int seven = 7; 
	switch (touchEvent.getAction()) { 
		case TouchEvent.PRIMARY_POINT_DOWN: 
			// 获取屏幕上点击的坐标 
			float floatX = touchEvent.getPointerPosition(touchEvent.getIndex()).getX(); 
			float floatY = touchEvent.getPointerPosition(touchEvent.getIndex()).getY(); 
			float radius = centerX / seven + padding / TWO; 
			boolean isScopeX = centerX - radius < floatX && centerX + radius > floatX; 
			boolean isScopeY = centerY - radius < floatY && centerY + radius > floatY; 
			if (isScopeX && isScopeY && !animatorVal.isRunning()) { 
				startAnimator(); 
			} 
			break; 
		case TouchEvent.PRIMARY_POINT_UP: 
			// 松开取消 
			invalidate(); 
			break; 
		default: 
			break; 
	} 
	return true; 
}

2.圆形转盘开始转动抽奖：给转盘指定一个随机的转动角度randomAngle，保证每次转动的角度是随机的（即每次抽到的奖品也是随机的），然后设置动画移动的曲线类型，这里抽奖设置的是Animator.CurveType.DECELERATE表示动画快速开始然后逐渐减速的曲线。动画结束后，转盘停止转动（即抽奖结束），会弹出抽中的奖品提示信息。

private void startAnimator() { 
	final int angle = 270; 
	startAngle = 0; 
	// 动画时长 
	final long animatorDuration = 4000L; 
	// 随机角度 
	int randomAngle = new SecureRandom().nextInt(CIRCLE); 
	animatorVal.setCurveType(Animator.CurveType.DECELERATE); 
	animatorVal.setDuration(animatorDuration); 
	animatorVal.setValueUpdateListener((AnimatorValue animatorValue, float value) -> { 
		startAngle = value * (CIRCLE * FIVE - randomAngle + angle); 
		invalidate(); 
	}); 
	stateChangedListener(animatorVal, randomAngle); 
	animatorVal.start(); 
}

9. 最终实现效果

【鸿蒙】HarMonyOS的自定义组件之抽奖大转盘

10. 代码示例

代码结构解读

为了方便您的学习，我们提供了自定义圆形抽奖转盘示例工程的代码，代码的工程结构描述如下：

【鸿蒙】HarMonyOS的自定义组件之抽奖大转盘

customcomponent：LuckyCirclePanComponent自定义圆形抽奖转盘组件类，绘制圆形抽奖转盘，并实现抽奖效果。
slice：MainAbilitySlice本示例教程起始页面，提供界面入口。
utils：工具类
- ColorUtils颜色工具类，对绘制圆盘所需RGB颜色进行封装。
- LogUtils日志打印类，对HiLog日志进行了封装。
- PixelMapUtils图片工具类，主要是加载本地图片资源，通过本地图片资源的resourceId，将图片转换成PixelMap类型。
- ToastUtils弹窗工具类，抽奖结束后，弹出抽奖结果信息。
MainAbility：主程序入口，DevEco Studio生成，未添加逻辑，无需变更。
MyApplication：DevEco Studio自动生成，无需变更。
resources：存放工程使用到的资源文件
- resources\base\element中存放DevEco studio自动生成的配置文件string.json，无需变更。
- resources\base\graphic中存放页面样式文件，本示例教程通过自定义组件完成，没有定义页面样式，无需变更。
- resources\base\layout中布局文件，本示例教程通过自定义组件完成，没有定义页面布局，无需变更。
- resources\base\media下存放图片资源，本示例教程使用了5张.png图片，用于设置与奖品相对应的图片，开发者可自行准备；icon.png由DevEco Studio自动生成，无需变更。
config.json：配置文件。

编写布局与样式

ability_main.xml布局文件。

<?xml version="1.0" encoding="utf-8"?> 
<DirectionalLayout 
        xmlns:ohos="http://schemas.huawei.com/res/ohos" 
        ohos:height="match_parent" 
        ohos:width="match_parent" 
        ohos:orientation="vertical"> 
    <Text 
            ohos:id="$+id:text_helloworld" 
            ohos:height="match_content" 
            ohos:width="match_content" 
            ohos:background_element="$graphic:background_ability_main" 
            ohos:layout_alignment="horizontal_center" 
            ohos:text="Hello World" 
            ohos:text_size="50" 
    /> 
</DirectionalLayout>

2.background_ability_main.xml样式文件

<?xml version="1.0" encoding="UTF-8" ?> 
<shape xmlns:ohos="http://schemas.huawei.com/res/ohos" 
       ohos:shape="rectangle"> 
    <solid 
            ohos:color="#FFFFFF"/> 
</shape>

业务逻辑代码

新建LuckyCirclePanComponent类，实现自定义组件，绘制圆形抽奖转盘，并实现抽奖效果。

public class LuckyCirclePanComponent extends Component implements Component.DrawTask, 
        Component.EstimateSizeListener, Component.TouchEventListener { 
    private static final int CIRCLE = 360; 
    private static final int TWO = 2; 
    private static final int THREE = 3; 
    private static final int FIVE = 5; 
 
    // 盘块的个数 
    private static final int COUNT = 6; 
 
    // 开始角度 
    private float startAngle = 0; 
 
    // 平均每份的角度 
    private float avgAngle = CIRCLE / COUNT; 
 
    // 边框间距 
    private int padding; 
 
    // 宽度和高度 
    private float width; 
    private float height; 
 
    // 中心的X，Y坐标 
    private float centerX; 
    private float centerY; 
 
    // 画内部扇形的画笔 
    private Paint paintInnerArc; 
 
    // 画内部扇形文字的画笔 
    private Paint paintArcText; 
 
    // 外部圆弧的画笔 
    private Paint paintOutCircle; 
 
    // 内部圆弧的画笔 
    private Paint paintCenterCircle; 
 
    // 中间文字的画笔 
    private Paint paintCenterText; 
 
    // 画转盘大指针的画笔 
    private Paint paintPointer; 
 
    // 画转盘小指针的画笔 
    private Paint paintSmallPoint; 
 
    // 画图片的画笔 
    private Paint paintImage; 
 
    // 画外圆外面的花瓣 
    private Paint paintFlower; 
 
    // 画五角星的画笔 
    private Paint paintFive; 
 
    // 每个盘块的颜色 
    private Color[] colors = {ColorUtils.ARC_PINK, ColorUtils.ARC_YELLOW, ColorUtils.ARC_BLUE, 
        ColorUtils.ARC_PINK, ColorUtils.ARC_YELLOW, ColorUtils.ARC_BLUE, }; 
 
    // 抽奖的文字 
    private String[] textArrs = {"华为手表", "华为平板", "恭喜发财", "华为手机", "华为耳机", "恭喜发财"}; 
 
     // 与文字对应的图片
    private PixelMap[] pixelMaps = {PixelMapUtils.createPixelMapByResId(ResourceTable.Media_icon, getContext()).get(),
            PixelMapUtils.createPixelMapByResId(ResourceTable.Media_icon, getContext()).get(),
            PixelMapUtils.createPixelMapByResId(ResourceTable.Media_icon, getContext()).get(),
            PixelMapUtils.createPixelMapByResId(ResourceTable.Media_icon, getContext()).get(),
            PixelMapUtils.createPixelMapByResId(ResourceTable.Media_icon, getContext()).get(),
            PixelMapUtils.createPixelMapByResId(ResourceTable.Media_icon, getContext()).get()};
 
    private List<PixelMapHolder> pixelMapHolderList; 
    private Context context; 
 
    // 动画 
    private AnimatorValue animatorVal = new AnimatorValue(); 
 
    /** 
     * constructor of LuckyCirclePanComponent 
     * 
     * @param context context 
     */ 
    public LuckyCirclePanComponent(Context context) { 
        super(context); 
        this.context = context; 
        // 初始化画笔 
        initPaint(); 
        // 获取屏幕的宽高度、中心点坐标，调用onEstimateSize方法 
        setEstimateSizeListener(this); 
        // 添加绘制任务，调用onDraw方法 
        addDrawTask(this); 
        // 实现点击中心圆盘区域位置开始抽奖功能，调用onTouchEvent方法 
        setTouchEventListener(this); 
    } 
 
    private void initPaint() { 
        final int size = 20; 
        padding = vp2px(size); 
 
        pixelMapToPixelMapHolder(); 
 
        paintInnerArc = new Paint(); 
        paintInnerArc.setAntiAlias(true); 
        paintInnerArc.setStyle(Paint.Style.FILL_STYLE); 
 
        paintArcText = new Paint(); 
        paintArcText.setAntiAlias(true); 
        paintArcText.setTextSize(padding); 
        paintArcText.setStyle(Paint.Style.FILL_STYLE); 
        paintArcText.setColor(ColorUtils.TEXT); 
 
        paintOutCircle = new Paint(); 
        paintOutCircle.setAntiAlias(true); 
        paintOutCircle.setStyle(Paint.Style.FILL_STYLE); 
 
        paintCenterCircle = new Paint(); 
        paintCenterCircle.setAntiAlias(true); 
        paintCenterCircle.setStyle(Paint.Style.FILL_STYLE); 
 
        paintPointer = new Paint(); 
        paintPointer.setAntiAlias(true); 
        paintPointer.setStyle(Paint.Style.FILL_STYLE); 
        paintPointer.setColor(ColorUtils.PAINT_POINTER); 
 
        paintCenterText = new Paint(); 
        paintCenterText.setAntiAlias(true); 
        paintCenterText.setTextSize(padding); 
        paintCenterText.setStyle(Paint.Style.FILL_STYLE); 
        paintCenterText.setColor(ColorUtils.TEXT); 
        paintCenterText.setTextAlign(TextAlignment.CENTER); 
 
        paintImage = new Paint(); 
        paintImage.setAntiAlias(true); 
        paintImage.setStrokeCap(Paint.StrokeCap.ROUND_CAP); 
        paintImage.setStyle(Paint.Style.STROKE_STYLE); 
 
        paintFlower = new Paint(); 
        paintFlower.setAntiAlias(true); 
        paintFlower.setStyle(Paint.Style.FILL_STYLE); 
 
        paintFive = new Paint(); 
        paintFive.setAntiAlias(true); 
        paintFive.setStyle(Paint.Style.FILL_STYLE); 
        paintFive.setColor(Color.YELLOW); 
 
        paintSmallPoint = new Paint(); 
        paintSmallPoint.setStyle(Paint.Style.FILL_STYLE); 
        paintSmallPoint.setColor(Color.WHITE); 
    } 
 
    @Override 
    public boolean onEstimateSize(int widthEstimateConfig, int heightEstimateConfig) { 
        int componentWidth = EstimateSpec.getSize(widthEstimateConfig); 
        int componentHeight = EstimateSpec.getSize(heightEstimateConfig); 
        this.width = componentWidth; 
        this.height = componentHeight; 
        centerX = this.width / TWO; 
        centerY = this.height / TWO; 
        setEstimatedSize( 
                EstimateSpec.getChildSizeWithMode(componentWidth, componentWidth, EstimateSpec.PRECISE), 
                EstimateSpec.getChildSizeWithMode(componentHeight, componentHeight, EstimateSpec.PRECISE) 
        ); 
        return true; 
    } 
 
    @Override 
    public void onDraw(Component component, Canvas canvas) { 
        // 将画布沿X、Y轴平移指定距离 
        canvas.translate(centerX, centerY); 
        // 画外部圆盘的花瓣 
        drawFlower(canvas); 
        // 画外部圆盘、小圈圈、五角星 
        drawOutCircleAndFive(canvas); 
        // 画内部扇形抽奖区域 
        drawInnerArc(canvas); 
        // 画内部扇形区域文字 
        drawArcText(canvas); 
        // 画内部扇形区域奖品对应的图片 
        drawImage(canvas); 
        // 画中心圆盘和指针 
        drawCenter(canvas); 
    } 
 
    private void drawFlower(Canvas canvas) { 
        float beginAngle = startAngle + avgAngle; 
        float radius = centerX - padding; 
        for (int i = 0; i < COUNT; i++) { 
            canvas.save(); 
            canvas.rotate(beginAngle, 0F, 0F); 
            paintFlower.setColor(ColorUtils.PAINT_FLOWER_YELLOW); 
            canvas.drawCircle(-radius / TWO, radius / TWO, radius / TWO, paintFlower); 
 
            paintFlower.setColor(ColorUtils.PAINT_FLOWER_PINK); 
            canvas.drawCircle(-radius / TWO, radius / TWO, (radius - padding) / TWO, paintFlower); 
            beginAngle += avgAngle; 
            canvas.restore(); 
        } 
    } 
 
    private void drawOutCircleAndFive(Canvas canvas) { 
        paintOutCircle.setColor(ColorUtils.PAINT_OUT_CIRCLE); 
        canvas.drawCircle(0F, 0F, centerX - padding, paintOutCircle); 
        float beginAngle = startAngle + avgAngle / THREE; 
        for (int i = 0; i < COUNT * THREE; i++) { 
            canvas.save(); 
            canvas.rotate(beginAngle, 0F, 0F); 
            if (0 == i % TWO) { 
                paintOutCircle.setColor(Color.WHITE); 
                canvas.drawCircle(centerX - padding - padding / TWO, 0F, vp2px(FIVE), paintOutCircle); 
            } else { 
                paintFiveStart(canvas); 
            } 
            beginAngle += avgAngle / THREE; 
            canvas.restore(); 
        } 
    } 
 
    private void paintFiveStart(Canvas canvas) { 
        // 画五角星的path 
        Path path = new Path(); 
        float[] points = fivePoints(centerX - padding - padding / TWO, 0F, padding); 
        for (int i = 0; i < points.length - 1; i = i + TWO) { 
            path.lineTo(points[i], points[i + 1]); 
        } 
        path.close(); 
        canvas.drawPath(path, paintFive); 
    } 
 
    private void drawInnerArc(Canvas canvas) { 
        float radius = Math.min(centerX, centerY) - padding * TWO; 
        RectFloat rect = new RectFloat(-radius, -radius, radius, radius); 
        for (int i = 0; i < COUNT; i++) { 
            paintInnerArc.setColor(colors[i]); 
            canvas.drawArc(rect, new Arc(startAngle, avgAngle, true), paintInnerArc); 
            startAngle += avgAngle; 
        } 
    } 
 
    private void drawArcText(Canvas canvas) { 
        for (int i = 0; i < COUNT; i++) { 
            // 创建绘制路径 
            Path circlePath = new Path(); 
            float radius = Math.min(centerX, centerY) - padding * TWO; 
            RectFloat rect = new RectFloat(-radius, -radius, radius, radius); 
            circlePath.addArc(rect, startAngle, avgAngle); 
            float measureWidth = paintArcText.measureText(textArrs[i]); 
            // 偏移量 
            float advance = (float) ((Math.sin(avgAngle / CIRCLE * Math.PI) * radius) - measureWidth / TWO); 
            canvas.drawTextOnPath(paintArcText, textArrs[i], circlePath, advance, radius / FIVE); 
            startAngle += avgAngle; 
        } 
    } 
 
    private void drawImage(Canvas canvas) { 
        float beginAngle = startAngle + avgAngle / TWO; 
        for (int i = 0; i < COUNT; i++) { 
            int imageWidth = pixelMaps[i].getImageInfo().size.width; 
            int imageHeight = pixelMaps[i].getImageInfo().size.height; 
            canvas.save(); 
            canvas.rotate(beginAngle, 0F, 0F); 
            // 指定图片在屏幕上显示的区域 
            RectFloat dst = new RectFloat(centerX / THREE, -imageHeight / TWO, 
                    centerX / THREE + imageWidth, imageHeight / TWO); 
            canvas.drawPixelMapHolderRect(pixelMapHolderList.get(i), dst, paintImage); 
            beginAngle += avgAngle; 
            canvas.restore(); 
        } 
    } 
 
    // 将pixelMap转换成PixelMapHolder 
    private void pixelMapToPixelMapHolder() { 
        pixelMapHolderList = new ArrayList<>(pixelMaps.length); 
        for (PixelMap pixelMap : pixelMaps) { 
            pixelMapHolderList.add(new PixelMapHolder(pixelMap)); 
        } 
    } 
 
    private void drawCenter(Canvas canvas) { 
        final int nine = 9; 
        final int seven = 7; 
        final int eighteen = 18; 
        // 画大指针 
        Path path = new Path(); 
        path.moveTo(-centerX / nine, 0F); 
        path.lineTo(centerX / nine, 0F); 
        path.lineTo(0F, -centerX / THREE); 
        path.close(); 
        canvas.drawPath(path, paintPointer); 
 
        // 画内部大圆 
        paintCenterCircle.setColor(ColorUtils.PAINT_POINTER); 
        canvas.drawCircle(0F, 0F, centerX / seven + padding / TWO, paintCenterCircle); 
        // 画内部小圆 
        paintCenterCircle.setColor(Color.WHITE); 
        canvas.drawCircle(0F, 0F, centerX / seven, paintCenterCircle); 
 
        // 画小指针 
        Path smallPath = new Path(); 
        smallPath.moveTo(-centerX / eighteen, 0F); 
        smallPath.lineTo(centerX / eighteen, 0F); 
        smallPath.lineTo(0F, -centerX / THREE + padding / TWO); 
        smallPath.close(); 
        canvas.drawPath(smallPath, paintSmallPoint); 
 
        // 画中心圆弧文字 
        Paint.FontMetrics fontMetrics = paintCenterText.getFontMetrics(); 
        float textHeight = (float) Math.ceil(fontMetrics.leading - fontMetrics.ascent); 
        canvas.drawText(paintCenterText, "开始", 0F, textHeight / THREE); 
    } 
 
    /** 
     * vp2px 将vp转换成px 
     * 
     * @param size size 
     * @return int 
     */ 
    public int vp2px(int size) { 
        int density = getResourceManager().getDeviceCapability().screenDensity / DeviceCapability.SCREEN_MDPI; 
        return size * density; 
    } 
 
    /** 
     * fivePoints 获取五角星的五个顶点 
     * 
     * @param pointXa 起始点A的x轴绝对位置 
     * @param pointYa 起始点A的y轴绝对位置 
     * @param sideLength 五角星的边长 
     * @return 五角星5个顶点坐标 
     */ 
    private static float[] fivePoints(float pointXa, float pointYa, float sideLength) { 
        final int eighteen = 18; 
        float pointXb = pointXa + sideLength / TWO; 
        double num = sideLength * Math.sin(Math.toRadians(eighteen)); 
        float pointXc = (float) (pointXa + num); 
        float pointXd = (float) (pointXa - num); 
        float pointXe = pointXa - sideLength / TWO; 
        float pointYb = (float) (pointYa + Math.sqrt(Math.pow(pointXc - pointXd, TWO) 
                - Math.pow(sideLength / TWO, TWO))); 
        float pointYc = (float) (pointYa + Math.cos(Math.toRadians(eighteen)) * sideLength); 
        float pointYd = pointYc; 
        float pointYe = pointYb; 
        float[] points = new float[]{pointXa, pointYa, pointXd, pointYd, pointXb, pointYb, 
            pointXe, pointYe, pointXc, pointYc, pointXa, pointYa}; 
        return points; 
    } 
 
    @Override 
    public boolean onTouchEvent(Component component, TouchEvent touchEvent) { 
        final int seven = 7; 
        switch (touchEvent.getAction()) { 
            case TouchEvent.PRIMARY_POINT_DOWN: 
                // 获取屏幕上点击的坐标 
                float floatX = touchEvent.getPointerPosition(touchEvent.getIndex()).getX(); 
                float floatY = touchEvent.getPointerPosition(touchEvent.getIndex()).getY(); 
                float radius = centerX / seven + padding / TWO; 
                boolean isScopeX = centerX - radius < floatX && centerX + radius > floatX; 
                boolean isScopeY = centerY - radius < floatY && centerY + radius > floatY; 
                if (isScopeX && isScopeY && !animatorVal.isRunning()) { 
                    startAnimator(); 
                } 
                break; 
            case TouchEvent.PRIMARY_POINT_UP: 
                // 松开取消 
                invalidate(); 
                break; 
            default: 
                break; 
        } 
        return true; 
    } 
 
    private void startAnimator() { 
        final int angle = 270; 
        startAngle = 0; 
        // 动画时长 
        final long animatorDuration = 4000L; 
        // 随机角度 
        int randomAngle = new SecureRandom().nextInt(CIRCLE); 
        animatorVal.setCurveType(Animator.CurveType.DECELERATE); 
        animatorVal.setDuration(animatorDuration); 
        animatorVal.setValueUpdateListener((AnimatorValue animatorValue, float value) -> { 
            startAngle = value * (CIRCLE * FIVE - randomAngle + angle); 
            invalidate(); 
        }); 
        stateChangedListener(animatorVal, randomAngle); 
        animatorVal.start(); 
    } 
 
    private void stateChangedListener(AnimatorValue animatorValue, int randomAngle) { 
        final int four = 4; 
        final int six = 6; 
        animatorValue.setStateChangedListener(new Animator.StateChangedListener() { 
            @Override 
            public void onStart(Animator animator) { 
            } 
 
            @Override 
            public void onStop(Animator animator) { 
            } 
 
            @Override 
            public void onCancel(Animator animator) { 
            } 
 
            @Override 
            public void onEnd(Animator animator) { 
                if (randomAngle >= 0 && randomAngle < avgAngle) { 
                    ToastUtils.showTips(context, "恭喜您中了一块华为手表"); 
                } else if (randomAngle >= avgAngle && randomAngle < TWO * avgAngle) { 
                    ToastUtils.showTips(context, "恭喜您中了一台华为平板"); 
                } else if (randomAngle >= TWO * avgAngle && randomAngle < THREE * avgAngle) { 
                    ToastUtils.showTips(context, "sorry，您没有中奖"); 
                } else if (randomAngle >= THREE * avgAngle && randomAngle < four * avgAngle) { 
                    ToastUtils.showTips(context, "恭喜您中了一部华为手机"); 
                } else if (randomAngle >= four * avgAngle && randomAngle < FIVE * avgAngle) { 
                    ToastUtils.showTips(context, "恭喜您中了一副华为耳机"); 
                } else if (randomAngle >= FIVE * avgAngle && randomAngle < six * avgAngle) { 
                    ToastUtils.showTips(context, "sorry，您没有中奖"); 
                } else { 
                    invalidate(); 
                } 
                animator.release(); 
            } 
 
            @Override 
            public void onPause(Animator animator) { 
            } 
 
            @Override 
            public void onResume(Animator animator) { 
            } 
        }); 
    } 
}

2.在MainAbilitySlice类中调用自定义圆形抽奖转盘组件类，显示圆形抽奖转盘。

public class MainAbilitySlice extends AbilitySlice { 
    private DirectionalLayout myLayout = new DirectionalLayout(this); 
 
    @Override 
    public void onStart(Intent intent) { 
        super.onStart(intent); 
        DirectionalLayout.LayoutConfig config = new DirectionalLayout.LayoutConfig( 
                DirectionalLayout.LayoutConfig.MATCH_PARENT, DirectionalLayout.LayoutConfig.MATCH_PARENT); 
        LuckyCirclePanComponent luckyCirclePanComponent = new LuckyCirclePanComponent(this); 
        luckyCirclePanComponent.setLayoutConfig(config); 
        myLayout.addComponent(luckyCirclePanComponent); 
        super.setUIContent(myLayout); 
    } 
 
    @Override 
    public void onActive() { 
        super.onActive(); 
    } 
 
    @Override 
    public void onForeground(Intent intent) { 
        super.onForeground(intent); 
    } 
}

3.新建ColorUtils类，对绘制圆盘所需RGB颜色进行封装。

public class ColorUtils { 
    /** 
     * arc pink color 
     */ 
    public static final Color ARC_PINK = new Color(Color.rgb(255, 163, 174)); 
 
    /** 
     * arc yellow Color 
     */ 
    public static final Color ARC_YELLOW = new Color(Color.rgb(255, 222, 78)); 
 
    /** 
     * arc blue color 
     */ 
    public static final Color ARC_BLUE = new Color(Color.rgb(118, 226, 219)); 
 
    /** 
     * text color 
     */ 
    public static final Color TEXT = new Color(Color.rgb(234, 134, 164)); 
 
    /** 
     * paint pointer Color 
     */ 
    public static final Color PAINT_POINTER = new Color(Color.rgb(246, 200, 216)); 
 
    /** 
     * paint flower yellow Color 
     */ 
    public static final Color PAINT_FLOWER_YELLOW = new Color(Color.rgb(243, 180, 104)); 
 
    /** 
     * paint flower pink Color 
     */ 
    public static final Color PAINT_FLOWER_PINK = new Color(Color.rgb(229, 136, 185)); 
 
    /** 
     * paint out circle color 
     */ 
    public static final Color PAINT_OUT_CIRCLE = new Color(Color.rgb(237, 109, 86)); 
 
    private ColorUtils() { 
    } 
}

4.新建PixelMapUtils类，加载本地图片资源，通过本地图片资源的resourceId，将图片转换成PixelMap类型。

public class PixelMapUtils { 
    private static final String TAG = "PixelMapUtils"; 
 
    private PixelMapUtils() { 
    } 
 
    private static byte[] readResource(Resource resource) { 
        final int bufferSize = 1024; 
        final int ioEnd = -1; 
        byte[] byteArray; 
        byte[] buffers = new byte[bufferSize]; 
        try (ByteArrayOutputStream output = new ByteArrayOutputStream()) { 
            while (true) { 
                int readLen = resource.read(buffers, 0, bufferSize); 
                if (readLen == ioEnd) { 
                    LogUtils.error(TAG, "readResource finish"); 
                    byteArray = output.toByteArray(); 
                    break; 
                } 
                output.write(buffers, 0, readLen); 
            } 
        } catch (IOException e) { 
            LogUtils.debug(TAG, "readResource failed " + e.getLocalizedMessage()); 
            return new byte[0]; 
        } 
        LogUtils.info(TAG, "readResource len: " + byteArray.length); 
        return byteArray; 
    } 
 
    /** 
     * Creates a {@code PixelMap} object based on the image resource ID. 
     * 
     * This method only loads local image resources. If the image file does not exist or the loading fails, 
     * {@code null} is returned. 
     * 
     * @param resourceId Indicates the image resource ID. 
     * @param slice Indicates the slice. 
     * @return Returns the image. 
     */ 
    public static Optional<PixelMap> createPixelMapByResId(int resourceId, Context slice) { 
        final float rotateDegrees = 90F; 
        ResourceManager manager = slice.getResourceManager(); 
        if (manager == null) { 
            return Optional.empty(); 
        } 
        try (Resource resource = manager.getResource(resourceId)) { 
            if (resource == null) { 
                return Optional.empty(); 
            } 
            ImageSource.SourceOptions srcOpts = new ImageSource.SourceOptions(); 
            srcOpts.formatHint = "image/png"; 
            ImageSource imageSource = ImageSource.create(readResource(resource), srcOpts); 
            if (imageSource == null) { 
                return Optional.empty(); 
            } 
            ImageSource.DecodingOptions decodingOpts = new ImageSource.DecodingOptions(); 
            decodingOpts.desiredSize = new Size(0, 0); 
            decodingOpts.desiredRegion = new Rect(0, 0, 0, 0); 
            decodingOpts.desiredPixelFormat = PixelFormat.ARGB_8888; 
            decodingOpts.rotateDegrees = rotateDegrees; 
 
            return Optional.of(imageSource.createPixelmap(decodingOpts)); 
        } catch (NotExistException | IOException e) { 
            return Optional.empty(); 
        } 
    } 
}

5.新建LogUtils类，对HiLog日志进行封装。

public class LogUtils { 
    private static final String TAG_LOG = "LogUtil"; 
 
    private static final HiLogLabel LABEL_LOG = new HiLogLabel(0, 0, LogUtils.TAG_LOG); 
 
    private static final String LOG_FORMAT = "%{public}s: %{public}s"; 
 
    private LogUtils() { 
    } 
 
    /** 
     * Print debug log 
     * 
     * @param tag log tag 
     * @param msg log message 
     */ 
    public static void debug(String tag, String msg) { 
        HiLog.debug(LABEL_LOG, LOG_FORMAT, tag, msg); 
    } 
 
    /** 
     * Print info log 
     * 
     * @param tag log tag 
     * @param msg log message 
     */ 
    public static void info(String tag, String msg) { 
        HiLog.info(LABEL_LOG, LOG_FORMAT, tag, msg); 
    } 
 
    /** 
     * Print warn log 
     * 
     * @param tag log tag 
     * @param msg log message 
     */ 
    public static void warn(String tag, String msg) { 
        HiLog.warn(LABEL_LOG, LOG_FORMAT, tag, msg); 
    } 
 
    /** 
     * Print error log 
     * 
     * @param tag log tag 
     * @param msg log message 
     */ 
    public static void error(String tag, String msg) { 
        HiLog.error(LABEL_LOG, LOG_FORMAT, tag, msg); 
    } 
}

6.新建ToastUtils类，对ToastDialg提示对话框进行封装。

import ohos.agp.window.dialog.ToastDialog;
import ohos.app.Context;

public class ToastUtils {

    public static void showTips(Context context,String info){
        new ToastDialog(context).setText(info).show();
    }
}

【鸿蒙】HarMonyOS的自定义组件之抽奖大转盘

1. 介绍

实现思路：

2. 搭建HarmonyOS环境

3. 基本步骤

4. 获取屏幕大小、中心点

5. 画外部圆盘

6. 画内部扇形抽奖区域

7. 画中心圆盘和指针

8. 实现抽奖功能

9. 最终实现效果

10. 代码示例

代码结构解读

编写布局与样式

业务逻辑代码

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