饼状统计图，带有标注线，都可以自行设定其多种参数选项

PieChartView

package cn.simon.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;

import java.util.ArrayList;
import java.util.List;

import cn.simon.R;

/** * 饼状统计图，带有标注线，都可以自行设定其多种参数选项 */
public class PieChartView extends View {
    

    private TextPaint mTextPaint;
    private float mTextWidth;
    private float mTextHeight;

    /** * 饼图半径 */
    private float pieChartCircleRadius = 100;

    private float textBottom;
    /** * 记录文字大小 */
    private float mTextSize = 14;

    /** * 饼图所占矩形区域（不包括文字） */
    private RectF pieChartCircleRectF = new RectF();

    /** * 饼状图信息列表 */
    private List<PieceDataHolder> pieceDataHolders = new ArrayList<>();


    /** * 标记线长度 */
    private float markerLineLength = 30f;

    public PieChartView(Context context) {
    
        super(context);
        init(null, 0);
    }

    public PieChartView(Context context, AttributeSet attrs) {
    
        super(context, attrs);
        init(attrs, 0);
    }

    public PieChartView(Context context, AttributeSet attrs, int defStyle) {
    
        super(context, attrs, defStyle);
        init(attrs, defStyle);
    }

    private void init(AttributeSet attrs, int defStyle) {
    
        // Load attributes
        final TypedArray a = getContext().obtainStyledAttributes(
                attrs, R.styleable.PieChartView, defStyle, 0);

        pieChartCircleRadius = a.getDimension(
                R.styleable.PieChartView_circleRadius,
                pieChartCircleRadius);

        mTextSize = a.getDimension(R.styleable.PieChartView_textSize, mTextSize)/getResources().getDisplayMetrics().density;

        a.recycle();

        // Set up a default TextPaint object
        mTextPaint = new TextPaint();
        mTextPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
        mTextPaint.setTextAlign(Paint.Align.LEFT);


        // Update TextPaint and text measurements from attributes
        invalidateTextPaintAndMeasurements();
    }

    private void invalidateTextPaintAndMeasurements() {
    

        mTextPaint.setTextSize(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, mTextSize, getContext().getResources().getDisplayMetrics()));

        Paint.FontMetrics fontMetrics = mTextPaint.getFontMetrics();
        mTextHeight = fontMetrics.descent - fontMetrics.ascent;
        textBottom = fontMetrics.bottom;
    }

    /** * 设置饼状图的半径 * * @param pieChartCircleRadius 饼状图的半径（px） */
    public void setPieChartCircleRadius(int pieChartCircleRadius) {
    

        this.pieChartCircleRadius = pieChartCircleRadius;

        invalidate();
    }

    /** * 设置标记线的长度 * * @param markerLineLength 标记线的长度（px） */
    public void setMarkerLineLength(int markerLineLength) {
    
        this.markerLineLength = markerLineLength;
    }

    @Override
    protected void onDraw(Canvas canvas) {
    
        super.onDraw(canvas);

        initPieChartCircleRectF();

        drawAllSectors(canvas);

    }

    private void drawAllSectors(Canvas canvas) {
    
        float sum = 0f;
        for (PieceDataHolder pieceDataHolder : pieceDataHolders) {
    
            sum += pieceDataHolder.value;
        }

        float sum2 = 0f;
        for (PieceDataHolder pieceDataHolder : pieceDataHolders) {
    
            float startAngel = sum2 / sum * 360;
            sum2 += pieceDataHolder.value;
            float sweepAngel = pieceDataHolder.value / sum * 360;

            drawSector(canvas, pieceDataHolder.color, startAngel, sweepAngel);
            drawMarkerLineAndText(canvas, pieceDataHolder.color, startAngel + sweepAngel / 2, pieceDataHolder.marker);
        }
    }

    private void initPieChartCircleRectF() {
    
        pieChartCircleRectF.left = getWidth() / 2 - pieChartCircleRadius;
        pieChartCircleRectF.top = getHeight() / 2 - pieChartCircleRadius;
        pieChartCircleRectF.right = pieChartCircleRectF.left + pieChartCircleRadius * 2;
        pieChartCircleRectF.bottom = pieChartCircleRectF.top + pieChartCircleRadius * 2;
    }

    /** * Gets the example dimension attribute value. * * @return The example dimension attribute value.(sp) */
    public float getTextSize() {
    
        return mTextSize;
    }

    /** * Sets the view's text dimension attribute value. In the PieChartView view, this dimension * is the font size. * * @param textSize The text dimension attribute value to use.(sp) */
    public void setTextSize(float textSize) {
    
        mTextSize = textSize;
        invalidateTextPaintAndMeasurements();
    }

    /** * 设置饼状图要显示的数据 * * @param data 列表数据 */
    public void setData(List<PieceDataHolder> data) {
    

        if (data != null) {
    
            pieceDataHolders.clear();
            pieceDataHolders.addAll(data);
        }

        invalidate();
    }

    /** * 绘制扇形 * * @param canvas 画布 * @param color 要绘制扇形的颜色 * @param startAngle 起始角度 * @param sweepAngle 结束角度 */
    protected void drawSector(Canvas canvas, int color, float startAngle, float sweepAngle) {
    

        Paint paint = new Paint();
        paint.setFlags(Paint.ANTI_ALIAS_FLAG);
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(color);

        canvas.drawArc(pieChartCircleRectF, startAngle, sweepAngle, true, paint);

    }

    /** * 绘制标注线和标记文字 * * @param canvas 画布 * @param color 标记的颜色 * @param rotateAngel 标记线和水平相差旋转的角度 */
    protected void drawMarkerLineAndText(Canvas canvas, int color, float rotateAngel, String text) {
    
        Paint paint = new Paint();
        paint.setFlags(Paint.ANTI_ALIAS_FLAG);
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(color);

        Path path = new Path();
        path.close();
        path.moveTo(getWidth() / 2, getHeight() / 2);
        final float x = (float) (getWidth() / 2 + (markerLineLength + pieChartCircleRadius) * Math.cos(Math.toRadians(rotateAngel)));
        final float y = (float) (getHeight() / 2 + (markerLineLength + pieChartCircleRadius) * Math.sin(Math.toRadians(rotateAngel)));
        path.lineTo(x, y);
        float landLineX;
        if (270f > rotateAngel && rotateAngel > 90f) {
    
            landLineX = x - 20;
        } else {
    
            landLineX = x + 20;
        }
        path.lineTo(landLineX, y);
        canvas.drawPath(path, paint);

        mTextPaint.setColor(color);
        if (270f > rotateAngel && rotateAngel > 90f) {
    
            float textWidth = mTextPaint.measureText(text);
            canvas.drawText(text, landLineX - textWidth, y + mTextHeight / 2 - textBottom, mTextPaint);

        } else {
    
            canvas.drawText(text, landLineX, y + mTextHeight / 2 - textBottom, mTextPaint);
        }

    }

    /** * 饼状图每块的信息持有者 */
    public static final class PieceDataHolder {
    

        /** * 每块扇形的值的大小 */
        private float value;

        /** * 扇形的颜色 */
        private int color;

        /** * 每块的标记 */
        private String marker;


        public PieceDataHolder(float value, int color, String marker) {
    
            this.value = value;
            this.color = color;
            this.marker = marker;
        }
    }

}

attrs_pie_chart_view.xml

<resources>
    <declare-styleable name="PieChartView">
        <attr name="circleRadius" format="dimension" />
        <attr name="textSize" format="dimension" />
        <attr name="exampleDrawable" format="color|reference" />
    </declare-styleable>
</resources>