android自定义view实现数字进度条

package com.tuya;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;
/**
 * Created by admin on 2016/12/19.
 */
public class DownLoadProgressView extends View {
 private Paint paint;//绘制进度条画笔
 private Paint textPaint;//绘制文字画笔
 private Paint dottePaint;//绘制灰色线画笔
 private int width;
 private int height;
 private int padding =5;
 private int value = 0;
 public DownLoadProgressView(Context context) {
  this(context,null);
 }
 public DownLoadProgressView(Context context, AttributeSet attrs) {
  this(context, attrs,0);
 }
 public DownLoadProgressView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  initPaint();
 }
 @Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
  super.onSizeChanged(w, h, oldw, oldh);
  width = w;
  height = h;
 }
 /**
  * 初始化画笔
  */
 private void initPaint() {
  paint = new Paint();
  paint.setAntiAlias(true);
  paint.setStrokeWidth(2);
  paint.setStyle(Paint.Style.FILL);
  paint.setColor(Color.BLUE);

  textPaint = new Paint();
  textPaint.setAntiAlias(true);
  textPaint.setStrokeWidth(3);
  textPaint.setStyle(Paint.Style.FILL);
  textPaint.setColor(Color.BLUE);
  textPaint.setTextSize(12);

  dottePaint = new Paint();
  dottePaint.setAntiAlias(true);
  dottePaint.setStrokeWidth(2);
  dottePaint.setStyle(Paint.Style.FILL);
  dottePaint.setColor(Color.parseColor("#e5e5e5"));
 }
 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  String str = value+"%";
  float strWidth = textPaint.measureText(value+"%")+padding;//绘制文字的宽度 +padding是为了防止在进度条加载完毕的时候文字绘制出现被切掉情况
  Rect rect = new Rect();
  textPaint.getTextBounds(str,0,str.length(),rect);
  canvas.drawLine(0,height/2,value*((width-strWidth)/100),height/2,paint);//绘制进度
  canvas.drawText(value+"%",value*((width-strWidth)/100)+padding,(height-rect.height())/2+2*padding,textPaint);//绘制进度文字 这个高度+2*padding是因为drawText是根据基线计算的,要准确的话要去求基线
  canvas.drawLine(value*((width-strWidth)/100)+strWidth+padding,height/2,width,height/2,dottePaint);//绘制灰色进度表示剩余多少
  postDelayed(new Runnable() {
   @Override
   public void run() {
    if(value<100){
     value++;
     postInvalidate();
    }
   }
  },100);
 }
}

<?xml version="1.0" encoding="utf-8"? 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="#7EC0EE" 
 <com.tuya.DownLoadProgressView
  android:id="@+id/dpv"
  android:layout_width="fill_parent"
  android:layout_height="30dp"
  android:layout_marginLeft="10dp"
  android:layout_marginRight="10dp"
  android:layout_marginTop="60dp"
   </com.tuya.DownLoadProgressView 
</RelativeLayout