观看大大博客照着写了个demo，注释都在代码里话不多说，上代码

public class MyAnalysisChart extends View {
    private Paint mPaint = new Paint();
    //颜色数组
    private int[] mColors = {0xFFCCFF00, 0xFF6495ED, 0xFFE32636, 0xFF800000, 0xFF808000, 0xFFFF8C69, 0xFF808080,
            0xFFE6B800, 0xFF7CFC00};
    //饼状图绘制初始角度
    private float mStartAngle = 0;
    //数据集合
    List<PieData> mData;

    //宽高
    private int mWidth, mHight;

    public MyAnalysisChart(Context context) {
        super(context, null);
    }

    public MyAnalysisChart(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setAntiAlias(true);  //是否抗锯齿
    }

    //首先测量宽高
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mWidth = w;
        mHight = h;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (null == mData)
            return;
        float currentStartAngle = mStartAngle;                    // 当前起始角度
        canvas.translate(mWidth / 2, mHight / 2);                // 将画布坐标原点移动到中心位置
        float r = (float) (Math.min(mWidth, mHight) / 2 * 0.8);  // 饼状图半径
        RectF rect = new RectF(-r, -r, r, r);                     // 饼状图绘制区域

        for (int i = 0; i < mData.size(); i++) {
            PieData pie = mData.get(i);
            mPaint.setColor(pie.getColor());
            canvas.drawArc(rect, currentStartAngle, pie.getAngle(), true, mPaint);
            currentStartAngle += pie.getAngle();
        }
    }



    //设置起始角度
    public void setCurrenStartAngle(int mStartAngle) {
        this.mStartAngle = mStartAngle;
        invalidate();//刷新
    }

    //设置数据
    public void setData(ArrayList<PieData> mData) {
        this.mData= mData;
        initData(mData); //初始化数据
        invalidate();//刷新
    }

    private void initData(ArrayList<PieData> mData) {
        if (null == mData || mData.size() == 0) {
            return;
        }
        float sumValue = 0;

        for (int i = 0; i <mData.size(); i++) {
            PieData pie =mData.get(i);

            sumValue += pie.getValue();    //计算数值和

            int j = i % mColors.length;   //设置颜色
            pie.setColor(mColors[j]);
        }
        float sumAngle = 0;
        for (int i = 0; i < mData.size(); i++) {
            PieData pie = mData.get(i);

            float percentage = pie.getValue() / sumValue;    //计算百分比
            float angle = percentage * 360;   //对应的角度
            pie.setPercentage(percentage); //设置角度
            pie.setAngle(angle);   //设置角度

            sumAngle += angle;
        }
    }

}

MainActivty插入伪数据

public class MainActivity extends AppCompatActivity {
    private ArrayList<PieData> mlist = new ArrayList<PieData>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        MyAnalysisChart myAnalysisChart = (MyAnalysisChart) findViewById(R.id.myasc);
        PieData pieData = new PieData("你好",10);
        PieData pieData1 = new PieData("你好1",20);
        PieData pieData2 = new PieData("你好2",30);
        PieData pieData3= new PieData("你好3",40);

        mlist.add(pieData);
        mlist.add(pieData1);
        mlist.add(pieData2);
        mlist.add(pieData3);

        myAnalysisChart.setData( mlist);


    }

xml布局调用自定义控件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="study.chengbing.com.mystudyview.MainActivity">

   <study.chengbing.com.mystudyview.MyAnalysisChart
       android:id="@+id/myasc"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content" />
</RelativeLayout>

OK，下面贴上运行效果

Paste_Image.png