由於專案中需要用到餅圖，用MpAndroidChart，當餅圖部分佔比很小時，描述文字重疊，所以自己重新繪製了餅圖，並提供餅圖各部分的點選監聽，效果圖如下：

繪製餅圖的類：

package com.karoline.views.bars;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import
 
 android.graphics.RectF;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import com.karoline.utils.SizeUtils;

import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by ${Karoline} on 2017/6/14.
 */
 


public class AssetKcPie extends View {//繼承View類
    private Context mContext;
    private Paint textPaint; 
    private Paint arcPaint;
    private Paint linePaint;

    private WeakReference<Bitmap> bitmapBuffer;
    private Canvas bitmapCanvas;

    private float distance;
    private float radius;
    private
 
 int barWidth,barHeight;
    private List<AssetKcData> datas;
    private List<AngleSE> angleSEs;
    private List<RectF> lengedRectes;
    private OnSelectedListener mListener;

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if(event.getAction() == MotionEvent.ACTION_DOWN){
            float actionX = event.getX(); //點選點的座標
            float actionY = event.getY();
            double distance = Math.sqrt(Math.pow(Math.abs(actionX-barWidth/2),2)+
                                Math.pow(Math.abs(actionY-barHeight/2),2));
            double angle = Math.atan((actionY-barHeight/2) /(actionX-barWidth/2)) /3.14 * 180 - 90;
            float X = barWidth/2,Y=(barHeight-lengedHeight)/2;
            if(actionX > X && actionY<Y){
                angle = 90-angle;
            } else if (actionX > X && actionY>Y) {
                angle = 90+angle;
            }else if (actionX < X && actionY>Y) {
                angle = 270-angle;
            }else if (actionX < X && actionY<Y) {
                angle = 270+angle;
            }

            if(angleSEs == null || angleSEs.size() == 0 || mListener == null) return false;

            for(int i=0;i<angleSEs.size();i++){
                if(distance <= radius){
                    if(angle > angleSEs.get(i).getStartAngle() && angle<angleSEs.get(i).getSweepAngle()){
                        mListener.onSelected(i); //當點選點在圓內且在扇形上時，觸發監聽事件
                    }
                }else if(lengedRectes.get(i).contains(actionX,actionY)){
                    mListener.onSelected(i); //當點選點在描述文字上時，觸發監聽事件(此處是當餅圖部分太小，無法點選時的補充)
                }
            }
            return false;
        }

        return super.onTouchEvent(event);
    }

    private float totalNum;

    private int lengedHeight = 0;
    private boolean isLengedVisible = false;

    public AssetKcPie(Context context) {
        super(context);
    }

    public AssetKcPie(Context context, AttributeSet attrs) {
        super(context, attrs); 

        mContext = context;

        textPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        textPaint.setColor(Color.BLACK);
        textPaint.setTextSize(SizeUtils.dp2px(context,11));

        arcPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        arcPaint.setTextSize(radius);

        linePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        linePaint.setColor(Color.DKGRAY);
        linePaint .setTextSize(3);

        distance = SizeUtils.dp2px(context,16);

        setRadius(SizeUtils.dp2px(context,80));

    }

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

    public void setRadius(float rs){
        this.radius = rs;
    }

    public void setData(List<AssetKcData> dataS,float total){
        this.datas = dataS;
        this.totalNum = total;
        invalidate();
    }

    public void setLenged(){ //設定是否繪製控制元件下方的描述
        isLengedVisible = true;
        lengedHeight = (int) SizeUtils.dp2px(mContext,32);
                setMeasuredDimension(onWidthMeasure(getMeasuredWidth()),onHeightMeasure(getMeasuredHeight()));
    }

    private void drawLenged(){ //繪製控制元件下面的描述
        lengedRectes = new ArrayList<>();
        Rect rect = new Rect();
        float lengedX = distance;
        float lengedY = barHeight - lengedHeight + distance;
        float totalWidth;
        for(int i = 0;i<datas.size();i++){
            RectF rectF = new RectF();
            textPaint.setTextSize(SizeUtils.dp2px(mContext,13));
            textPaint.setFakeBoldText(true);
            textPaint.setShadowLayer(5,4,4,Color.GRAY);
            textPaint.getTextBounds(datas.get(i).getDesc(),0,datas.get(i).getDesc().length(),rect);
            arcPaint.setTextSize(distance/2);
            arcPaint.setColor(datas.get(i).getColor());

            if(!TextUtils.isEmpty(datas.get(i).getDesc())){ //當描述大於一行時，在下一行繪製

                totalWidth = lengedX + distance/2 + 4 + rect.width() +distance;
                if(totalWidth > barWidth){//判斷描述的長度是否大於一行
                    lengedY = lengedY +distance;
                    lengedX = distance;
                }

                bitmapCanvas.drawRect(lengedX,lengedY-distance/2,lengedX+distance/2,lengedY ,arcPaint);//繪製描述的顏色方塊
                rectF.left = lengedX;
                rectF.top = lengedY-distance;
                lengedX = lengedX + distance/2 + 4;
                bitmapCanvas.drawText(datas.get(i).getDesc(),lengedX,lengedY,textPaint);//繪製描述的顏色文字
                lengedX = lengedX + rect.width() + distance;
                rectF.right = lengedX;
                rectF.bottom = lengedY + distance;
                lengedRectes.add(rectF);//將描述說在的Recf存起來備用(注意放大點選的熱區)
            }
        }

        bitmapCanvas.save();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int Width = onWidthMeasure(widthMeasureSpec); //計算控制元件的寬度
        int height = onHeightMeasure(heightMeasureSpec);//計算控制元件的高度
        setMeasuredDimension(Width,height);
    }

    //當控制元件的寬度，高度發生變化是呼叫
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh); 
        int width = getMeasuredWidth();
        int hight = getMeasuredHeight();
        if (bitmapBuffer == null
                || (bitmapBuffer.get().getWidth() != width)
                || (bitmapBuffer.get().getHeight() != hight)) {

            if (width > 0 && hight > 0) {

                bitmapBuffer = new WeakReference<Bitmap>(Bitmap.createBitmap(width, hight, Bitmap.Config.ARGB_4444));
                bitmapCanvas = new Canvas(bitmapBuffer.get());
            }
        }
    }

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

        canvas.save();
        bitmapBuffer.get().eraseColor(Color.TRANSPARENT);//繪製時先擦除畫板上的內容(用於更新介面)

        if(datas != null && datas.size() > 0 ){
            if(isLengedVisible){
                drawLenged();
            }

            angleSEs = new ArrayList<>();

            RectF arcRect = new RectF(barWidth/2-radius,(barHeight-lengedHeight)/2 - radius,
                    barWidth/2+radius,(barHeight-lengedHeight)/2 + radius);//圓形所在的RectF，圓心與控制元件中心重疊
            float startAngle = -90,sweepAngle = 0;
            float perAngle = totalNum/360;//每一度的數量
            String desc;
            float lineAngle;

            Rect rect = new Rect();
            for(int i=0;i<datas.size();i++){
                sweepAngle = datas.get(i).getNum()/perAngle; //當前值的度數
                arcPaint.setColor(datas.get(i).getColor());
                bitmapCanvas.drawArc(arcRect,startAngle,sweepAngle,true,arcPaint);//繪製扇形
                angleSEs.add(new AngleSE(startAngle,sweepAngle+startAngle));

                lineAngle = startAngle+ sweepAngle/2;//繪製描述文字的指示線，從扇形中間開始
                desc = datas.get(i).getDesc()+","+datas.get(i).getSNum();
                drwaLineAndText(sweepAngle,lineAngle,desc,rect,i);

                startAngle += sweepAngle; *//開始角度變為扇形結束的角度，下次繪製時從前一個扇形的結束區繪製*
            }
            bitmapCanvas.save();
            bitmapCanvas.restore();
        }

        Rect displayRect = new Rect(0,0,barWidth,barHeight);
        Rect det = new Rect(0,0,getWidth(),getHeight());

        canvas.drawBitmap(bitmapBuffer.get(),displayRect,det,null);
        canvas.restore();
    }

    private void drwaLineAndText(float sweepAngle,float lineAngle,String desc,Rect rect,int i){
        float lineStartX,lineStartY ,lineEndX,lineEndY ;

        lineStartX   =   barWidth/2   +   (radius- distance)   *  (float) Math.cos(lineAngle *   3.14   /180 );
        lineStartY   =   (barHeight-lengedHeight)/2   +   (radius- distance)  *   (float) Math.sin(lineAngle   *   3.14/180);
        if(Math.abs(sweepAngle) <= 30){ //當偏轉角度小於30°時，增加指示線的長度，避免描述文字重疊
            float num = (datas.size() - i)%3;
            lineEndX   =   barWidth/2   +   (radius+ distance*num*1f)   *  (float) Math.cos(lineAngle *   3.14   /180 );
            lineEndY   =   (barHeight-lengedHeight)/2   +   (radius+ distance*num*1f)  *   (float) Math.sin(lineAngle   *   3.14   /180);
        }else {
            lineEndX   =   barWidth/2   +   (radius+ distance)   *  (float) Math.cos(lineAngle *   3.14   /180 );
            lineEndY   =   (barHeight-lengedHeight)/2   +   (radius+ distance)  *   (float) Math.sin(lineAngle   *   3.14   /180);
        }
        bitmapCanvas.drawLine(lineStartX,lineStartY,lineEndX,lineEndY,linePaint);

        textPaint.getTextBounds(desc,0,desc.length(),rect);
        textPaint.setTextSize(SizeUtils.dp2px(mContext,11));
        textPaint.setFakeBoldText(false);
        textPaint.setShadowLayer(0,0,0,Color.TRANSPARENT);
        if (lineStartX>barWidth/2) { //當指示線位於餅圖右側時，在右側繪製第二條指示線及文字
            bitmapCanvas.drawLine(lineEndX,lineEndY,lineEndX+distance/2,lineEndY,linePaint);
            bitmapCanvas.drawText(desc,lineEndX+distance/2+4,lineEndY+rect.height()/2,textPaint);
        }else {//當指示線位於餅圖左側時，在左側繪製第二條指示線及文字

            bitmapCanvas.drawLine(lineEndX,lineEndY,lineEndX-distance/2,lineEndY,linePaint);
            bitmapCanvas.drawText(desc,lineEndX-distance/2-4-rect.width(),lineEndY+rect.height()/2,textPaint);
        }
    }

    private int onWidthMeasure(int width){
        int mode = MeasureSpec.getMode(width);
        int size = MeasureSpec.getSize(width);

        if(mode == MeasureSpec.EXACTLY){
            barWidth = size;
        }else if(mode == MeasureSpec.AT_MOST){
            barWidth = width - getPaddingLeft() - getPaddingRight();
        }
        return barWidth;
    }


    private int onHeightMeasure(int height){
        int mode1 = MeasureSpec.getMode(height);
        int size1 = MeasureSpec.getSize(height);
        int minSize = (int) SizeUtils.dp2px(mContext,120);
        if(mode1 == MeasureSpec.EXACTLY){
            barHeight = size1;
        }else { //當控制元件的高度為wrapContet時計算控制元件的高度
            if(datas != null && datas.size()>0){
                barHeight = (int) radius*2 + lengedHeight + (int) distance*2 + (int) distance*datas.size() ;
            }else {
                barHeight = minSize - getPaddingTop() - getPaddingBottom();
            }
        }

        return barHeight;
    }

    public void setOnSelectedListener(OnSelectedListener l){
        mListener = l;
    }

    public class AngleSE{
        private float startAngle;
        private float sweepAngle;

        public AngleSE(float startAngle, float sweepAngle) {
            this.startAngle = startAngle;
            this.sweepAngle = sweepAngle;
        }

        public float getStartAngle() {
            return startAngle;
        }

        public float getSweepAngle() {
            return sweepAngle;
        }
    }

    public interface OnSelectedListener{ //點選監聽介面
        void onSelected(int position);
    }
}

呼叫示例：

package com.karoline.uiviews;

import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

import com.karoline.R;
import com.karoline.codelibrary.BaseToolBarActivity;
import com.karoline.views.bars.AssetKcData;
import com.karoline.views.bars.AssetKcPie;
import com.karoline.views.bars.AssetLenged;

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

import butterknife.BindView;

public class AsssetKcActivity extends BaseToolBarActivity implements AssetKcPie.OnSelectedListener {
    @BindView(R.id.assetkc_desc)
    TextView assetkcDesc;
    @BindView(R.id.assetkc_chart)
    AssetKcPie assetkcPie;
    @BindView(R.id.assetkc_desc1)
    TextView assetkcDesc1;
    @BindView(R.id.assetkc_chart1)
    AssetKcPie assetkcChart1;
    @BindView(R.id.assetkc_lenged)
    AssetLenged assetkcLenged;

    private int mode = 1;
    private List<Integer> perColorList;
    private List<String> descList = new ArrayList<>();
    private List<AssetKcData> kcDatas;


    @Override
    protected int getContentView() {
        return R.layout.activity_assset_kc;
    }

    @Override
    protected void init(Bundle savedInstanceState) {
        setTitle("庫存概覽");
        assetkcPie.setOnSelectedListener(this);//新增監聽
        assetkcPie.setLenged();

        assetkcDesc1.setText("");

        kcDatas = new ArrayList<>();
        perColorList = new ArrayList<>();
        perColorList.add(Color.parseColor("#f36c60"));
        perColorList.add(Color.parseColor("#fba6c8"));
        perColorList.add(Color.parseColor("#7986cb"));
        perColorList.add(Color.parseColor("#4fc3f7"));
        perColorList.add(Color.parseColor("#cfd8dc"));
        perColorList.add(Color.parseColor("#4db6ac"));
        perColorList.add(Color.parseColor("#aed581"));
        perColorList.add(Color.parseColor("#fff176"));
        perColorList.add(Color.parseColor("#ffb74d"));


        updateView();
    }


    private void updateView() {
        List<AssetKcData> list = new ArrayList<>();
        list.add(new AssetKcData(Color.rgb(205, 92, 92), "工器具", 318243f));
        list.add(new AssetKcData(Color.rgb(255, 193, 37), "消耗品", 674937f));
        list.add(new AssetKcData(Color.parseColor("#cfd8dc"), "設施裝置工裝", 212664f));
        list.add(new AssetKcData(Color.rgb(10, 149, 237), "原材料", 35420464f));
        assetkcPie.setData(list, 318243 + 674937 + 212664 + 35420464);
    }

    @Override
    public void onSelected(int position) {
        List<AssetKcData> list = new ArrayList<>();
        switch (position) {
            case 0:
                assetkcDesc1.setText("工器具金額");
                assetkcChart1.setVisibility(View.VISIBLE);
                list.clear();
                list.add(new AssetKcData(perColorList.get(0), "電動工具", 38189.16f));
                list.add(new AssetKcData(perColorList.get(1), "手動工具", 25459.44f));
                list.add(new AssetKcData(perColorList.get(2), "儀器儀表", 12729.72f));
                list.add(new AssetKcData(perColorList.get(3), "照明燈具", 12729.72f));
                list.add(new AssetKcData(perColorList.get(4), "通訊工具", 25459.44f));
                list.add(new AssetKcData(perColorList.get(5), "雜項工具", 12729.72f));

                descList.clear();
                descList.add("電動工具");
                descList.add("手動工具");
                descList.add("儀器儀表");
                descList.add("照明燈具");
                descList.add("通訊工具");
                descList.add("雜項工具");

                assetkcChart1.setData(list, 127297.20f);
                assetkcLenged.setData(perColorList, descList);
                break;
            case 1:
                assetkcDesc1.setText("消耗品金額");
                assetkcChart1.setVisibility(View.VISIBLE);
                list.clear();
                list.add(new AssetKcData(perColorList.get(0), "刀具", 134987.4f));
                list.add(new AssetKcData(perColorList.get(1), "防寒防汛", 53994.96f));
                list.add(new AssetKcData(perColorList.get(2), "勞防用品", 80992.44f));

                descList.clear();
                descList.add("刀具");
                descList.add("防寒防汛");
                descList.add("勞防用品");

                assetkcChart1.setData(list, 269974.8f);
                assetkcLenged.setData(perColorList, descList);
                break;
            case 2:
                assetkcDesc1.setText("設施裝置工裝金額");
                assetkcChart1.setData(null, 100f);
                assetkcLenged.setData(null, null);
                break;
            case 3:
                assetkcDesc1.setText("原材料金額");
                assetkcChart1.setVisibility(View.VISIBLE);
                list.clear();
                list.add(new AssetKcData(perColorList.get(0), "備品備件（專用)", 1416818.56f));
                list.add(new AssetKcData(perColorList.get(1), "備品備件（通用）", 1558500.416f));
                list.add(new AssetKcData(perColorList.get(2), "緊韌體", 4250455.68f));
                list.add(new AssetKcData(perColorList.get(3), "水暖配件", 708409.28f));
                list.add(new AssetKcData(perColorList.get(4), "電器電料", 2833637.12f));
                list.add(new AssetKcData(perColorList.get(5), "燈類", 2125227.84f));
                list.add(new AssetKcData(perColorList.get(6), "輔料", 566727.424f));
                list.add(new AssetKcData(perColorList.get(7), "材料", 283363.712f));
                list.add(new AssetKcData(perColorList.get(8), "化工原料", 425045.568f));

                descList.clear();
                descList.add("備品備件（專用)");
                descList.add("備品備件（通用）");
                descList.add("緊韌體");
                descList.add("水暖配件");
                descList.add("電器電料");
                descList.add("燈類");
                descList.add("輔料");
                descList.add("材料");
                descList.add("化工原料");

                assetkcChart1.setData(list, 14168185.6f);
                assetkcLenged.setData(perColorList, descList);
                break;
        }
    }
}

附呼叫示例的xml檔案：

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#e0f7fa"
        android:padding="16dp"
        android:orientation="vertical">

        <TextView
            android:id="@+id/assetkc_desc"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="當前庫存金額"
            android:textSize="16sp" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.karoline.views.bars.AssetKcPie
                android:id="@+id/assetkc_chart"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="#e0f7fa"
                android:gravity="center"
                android:minHeight="220dp" />
        </LinearLayout>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#fff"
        android:padding="16dp"
        android:orientation="vertical">

        <TextView
            android:id="@+id/assetkc_desc1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="當前庫存金額"
            android:textSize="16sp" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.karoline.views.bars.AssetKcPie
                android:id="@+id/assetkc_chart1"
                android:layout_width="match_parent"
                android:layout_height="280dp"
                android:gravity="center" />
        </LinearLayout>
        <com.karoline.views.bars.AssetLenged
            android:id="@+id/assetkc_lenged"
            android:layout_width="match_parent"
            android:layout_height="72dp" />
    </LinearLayout>
    </LinearLayout>
</ScrollView>