for (int i = 0;i < starCount;i++) {
   starEmptyDrawable.setBounds(starSize * i, 0, starSize * (i + 1), starSize);
   starEmptyDrawable.draw(canvas);
  }

for (int i = 0;i < starCount;i++) {
   starEmptyDrawable.setBounds(starSize * i, 0, starSize * (i + 1), starSize);
   starEmptyDrawable.draw(canvas);
  }
  for (int i = 0;i < starCount -1;i++) {
   starFillDrawable.setBounds(starSize * i, 0, starSize * (i + 1), starSize);
   starFillDrawable.draw(canvas);
  }

private Bitmap drawableToBitmap(Drawable drawable)
 {
  if (drawable == null)return null;
  Bitmap bitmap = Bitmap.createBitmap(starSize, starSize, Bitmap.Config.ARGB_8888);
  Canvas canvas = new Canvas(bitmap);
  drawable.setBounds(0, 0, starSize, starSize);
  drawable.draw(canvas);
  return bitmap;
 }

paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(new BitmapShader(starFillBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));

package com.dming.starbar;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

/**
 * Created by DMing on 2016/7/18.
 *
 */
public class StarBar extends View{
 private int starDistance = 0; //星星间距
 private int starCount = 5; //星星个数
 private int starSize;  //星星高度大小，星星一般正方形，宽度等于高度
 private float starMark = 0.0F; //评分星星
 private Bitmap starFillBitmap; //亮星星
 private Drawable starEmptyDrawable; //暗星星
 private OnStarChangeListener onStarChangeListener;//监听星星变化接口
 private Paint paint;   //绘制星星画笔
 private boolean integerMark = false;
 public StarBar(Context context, AttributeSet attrs) {
  super(context, attrs);
  init(context, attrs);
 }

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

 /**
  * 初始化UI组件
  *
  * @param context
  * @param attrs
  */
 private void init(Context context, AttributeSet attrs){
  setClickable(true);
  TypedArray mTypedArray = context.obtainStyledAttributes(attrs, R.styleable.RatingBar);
  this.starDistance = (int) mTypedArray.getDimension(R.styleable.RatingBar_starDistance, 0);
  this.starSize = (int) mTypedArray.getDimension(R.styleable.RatingBar_starSize, 20);
  this.starCount = mTypedArray.getInteger(R.styleable.RatingBar_starCount, 5);
  this.starEmptyDrawable = mTypedArray.getDrawable(R.styleable.RatingBar_starEmpty);
  this.starFillBitmap = drawableToBitmap(mTypedArray.getDrawable(R.styleable.RatingBar_starFill));
  mTypedArray.recycle();

  paint = new Paint();
  paint.setAntiAlias(true);
  paint.setShader(new BitmapShader(starFillBitmap, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
 }

 /**
  * 设置是否需要整数评分
  * @param integerMark
  */
 public void setIntegerMark(boolean integerMark){
  this.integerMark = integerMark;
 }

 /**
  * 设置显示的星星的分数
  *
  * @param mark
  */
 public void setStarMark(float mark){
  if (integerMark) {
   starMark = (int)Math.ceil(mark);
  }else {
   starMark = Math.round(mark * 10) * 1.0f / 10;
  }
  if (this.onStarChangeListener != null) {
   this.onStarChangeListener.onStarChange(starMark); //调用监听接口
  }
  invalidate();
 }

 /**
  * 获取显示星星的数目
  *
  * @return starMark
  */
 public float getStarMark(){
  return starMark;
 }


 /**
  * 定义星星点击的监听接口
  */
 public interface OnStarChangeListener {
  void onStarChange(float mark);
 }

 /**
  * 设置监听
  * @param onStarChangeListener
  */
 public void setOnStarChangeListener(OnStarChangeListener onStarChangeListener){
  this.onStarChangeListener = onStarChangeListener;
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  setMeasuredDimension(starSize * starCount + starDistance * (starCount - 1), starSize);
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  if (starFillBitmap == null || starEmptyDrawable == null) {
   return;
  }
  for (int i = 0;i < starCount;i++) {
   starEmptyDrawable.setBounds((starDistance + starSize) * i, 0, (starDistance + starSize) * i + starSize, starSize);
   starEmptyDrawable.draw(canvas);
  }
  if (starMark > 1) {
   canvas.drawRect(0, 0, starSize, starSize, paint);
   if(starMark-(int)(starMark) == 0) {
    for (int i = 1; i < starMark; i++) {
     canvas.translate(starDistance + starSize, 0);
     canvas.drawRect(0, 0, starSize, starSize, paint);
    }
   }else {
    for (int i = 1; i < starMark - 1; i++) {
     canvas.translate(starDistance + starSize, 0);
     canvas.drawRect(0, 0, starSize, starSize, paint);
    }
    canvas.translate(starDistance + starSize, 0);
    canvas.drawRect(0, 0, starSize * (Math.round((starMark - (int) (starMark))*10)*1.0f/10), starSize, paint);
   }
  }else {
   canvas.drawRect(0, 0, starSize * starMark, starSize, paint);
  }
 }


 @Override
 public boolean onTouchEvent(MotionEvent event) {
  int x = (int) event.getX();
  if (x < 0) x = 0;
  if (x > getMeasuredWidth()) x = getMeasuredWidth();
  switch(event.getAction()){
   case MotionEvent.ACTION_DOWN: {
    setStarMark(x*1.0f / (getMeasuredWidth()*1.0f/starCount));
    break;
   }
   case MotionEvent.ACTION_MOVE: {
    setStarMark(x*1.0f / (getMeasuredWidth()*1.0f/starCount));
    break;
   }
   case MotionEvent.ACTION_UP: {
    break;
   }
  }
  invalidate();
  return super.onTouchEvent(event);
 }

 /**
  * drawable转bitmap
  *
  * @param drawable
  * @return
  */
 private Bitmap drawableToBitmap(Drawable drawable)
 {
  if (drawable == null)return null;
  Bitmap bitmap = Bitmap.createBitmap(starSize, starSize, Bitmap.Config.ARGB_8888);
  Canvas canvas = new Canvas(bitmap);
  drawable.setBounds(0, 0, starSize, starSize);
  drawable.draw(canvas);
  return bitmap;
 }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="RatingBar">
  <!--星星间距-->
  <attr format="dimension" name="starDistance"/>
  <!--星星大小-->
  <attr format="dimension" name="starSize"/>
  <!--星星个数-->
  <attr format="integer" name="starCount"/>
  <!--星星空图-->
  <attr format="reference" name="starEmpty"/>
  <!--星星满图-->
  <attr format="reference" name="starFill"/>
 </declare-styleable>

</resources>

 <com.dming.starbar.StarBar
  android:id="@+id/starBar"
  android:layout_below="@+id/display"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  ratingbar:starEmpty="@drawable/star_empty"
  ratingbar:starFill="@drawable/star_full"
  ratingbar:starDistance="5dp"
  ratingbar:starCount="8"
  ratingbar:starSize="30dp"/>