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public class ViewData {
	public String name; //名字
	public int value;   //数值

	public int color;   //颜色
	public float percentage; //百分比
	public float angle; //角度

	public ViewData(int value, String name) {
		this.value = value;
		this.name = name;
	}
}

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public void drawText(@NonNull String text, float x, float y, @NonNull Paint paint) {
  	......
}

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public class ViewData {
    public String name; //名字
    public int value;   //数值

    public int color;   //颜色
    public float percentage; //百分比
    public float angle; //角度

    public ViewData(int value, String name) {
		this.value = value;
		this.name = name;
    }
}

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	public class MyView extends View {
		    private int[] mColors = {Color.BLUE, Color.DKGRAY, Color.CYAN, Color.RED, Color.GREEN};
		    private Paint paint;    //画笔
		    private ArrayList<ViewData> viewDatas;    //数据集
		    private int w;          //View宽高
		    private int h;
		    private RectF rectF;    //矩形

	    public MyView(Context context) {
			super(context);
			initPaint();    //设置画笔
	    }

	    //设置数据
	    public void setData(ArrayList<ViewData> viewDatas) {
			this.viewDatas = viewDatas;
			initData();     //设置数据的百分度和角度
			invalidate();   //刷新UI
	    }

	    public MyView(Context context, AttributeSet attrs) {
			super(context, attrs);
			initPaint();
	    }

	    public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
			super(context, attrs, defStyleAttr);
			initPaint();
	    }

	    //初始化画笔
	    private void initPaint() {
			paint = new Paint();
			//设置画笔默认颜色
			paint.setColor(Color.WHITE);
			//设置画笔模式：填充
			paint.setStyle(Paint.Style.FILL);
			//
			paint.setTextSize(30);
			//初始化区域
			rectF = new RectF();
	    }

	    //确定View大小
	    @Override
	    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
			super.onSizeChanged(w, h, oldw, oldh);
			this.w = w;     //获取宽高
			this.h = h;
	    }

	    @Override
	    protected void onDraw(Canvas canvas) {
			super.onDraw(canvas);
			canvas.translate(w / 2, h / 2);             //将画布坐标原点移到中心位置
			float currentStartAngle = 0;                //起始角度
			float r = (float) (Math.min(w, h) / 2);     //饼状图半径(取宽高里最小的值)
			rectF.set(-r, -r, r, r);                    //设置将要用来画扇形的矩形的轮廓
			for (int i = 0; i < viewDatas.size(); i++) {
			    ViewData viewData = viewDatas.get(i);
			    paint.setColor(viewData.color);
			    //绘制扇形(通过绘制圆弧)
			    canvas.drawArc(rectF, currentStartAngle, viewData.angle, true, paint);
			    //绘制扇形上文字
			    float textAngle = currentStartAngle + viewData.angle / 2;    //计算文字位置角度
			    paint.setColor(Color.BLACK);
			    float x = (float) (r / 2 * Math.cos(textAngle * Math.PI / 180));    //计算文字位置坐标
			    float y = (float) (r / 2 * Math.sin(textAngle * Math.PI / 180));
			    paint.setColor(Color.YELLOW);        //文字颜色
			    canvas.drawText(viewData.name, x, y, paint);    //绘制文字

			    currentStartAngle += viewData.angle;     //改变起始角度
			}
	    }

	    private void initData() {
			if (null == viewDatas || viewDatas.size() == 0) {
			    return;
			}

			float sumValue = 0;                 //数值和
			for (int i = 0; i < viewDatas.size(); i++) {
				    ViewData viewData = viewDatas.get(i);
				    sumValue += viewData.value;
				    int j = i % mColors.length;     //设置颜色
				    viewData.color = mColors[j];
			}

			for (ViewData data : viewDatas) {
			    float percentage = data.value / sumValue;    //计算百分比
			    float angle = percentage * 360;           //对应的角度
			    data.percentage = percentage;
			    data.angle = angle;
			}
	    }
	}