Android自定义View倒计时圆

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <declare-styleable name="countdownview">
    <!--颜色-->
    <attr name="ringcolor" format="color" />
    <!-- 进度文本的字体大小 -->
    <attr name="progresstextsize" format="dimension" />
    <!-- 圆环宽度 -->
    <attr name="ringwidth" format="float" />
    <!--进度文本颜色-->
    <attr name="progresstextcolor" format="color"/>
    <!--倒计时-->
    <attr name="countdowntime" format="integer"/>
  </declare-styleable>
</resources>

import android.content.context;

/**
 * created by 王 on 2017/10/21.
 */

public class displayutil {
  /**
   * 将px装换成dp，保证尺寸不变
   * @param context
   * @param pxvalue
   * @return
   */
  public static int px2dp(context context, float pxvalue){
    float density = context.getresources().getdisplaymetrics().density;//得到设备的密度
    return (int) (pxvalue/density+0.5f);
  }
  public static int dp2px(context context,float dpvalue){
    float density = context.getresources().getdisplaymetrics().density;
    return (int) (dpvalue*density+0.5f);
  }
  public static int px2sp(context context,float pxvalue){
    float scaledensity = context.getresources().getdisplaymetrics().scaleddensity;//缩放密度
    return (int) (pxvalue/scaledensity+0.5f);
  }
  public static int sp2px(context context,float spvalue) {
    float scaledensity = context.getresources().getdisplaymetrics().scaleddensity;
    return (int) (spvalue*scaledensity+0.5f);
  }
}

import android.animation.animator;
import android.animation.animatorlisteneradapter;
import android.animation.valueanimator;
import android.content.context;
import android.content.res.typedarray;
import android.graphics.canvas;
import android.graphics.paint;
import android.graphics.rectf;
import android.util.attributeset;
import android.view.view;
import android.view.animation.linearinterpolator;

/**
 * created by 王 on 2017/10/21.
 */

public class countdownview extends view{
  //圆轮颜色
  private int mringcolor;
  //圆轮宽度
  private float mringwidth;
  //圆轮进度值文本大小
  private int mringprogesstextsize;
  //宽度
  private int mwidth;
  //高度
  private int mheight;
  private paint mpaint;
  //圆环的矩形区域
  private rectf mrectf;
  //
  private int mprogesstextcolor;
  private int mcountdowntime;
  private float mcurrentprogress;
  private oncountdownfinishlistener mlistener;

  public countdownview(context context) {
    this(context, null);
  }

  public countdownview(context context, attributeset attrs) {
    this(context, attrs, 0);
  }

  public countdownview(context context, attributeset attrs, int defstyleattr) {
    super(context, attrs, defstyleattr);
    typedarray a = context.obtainstyledattributes(attrs, r.styleable.countdownview);
    mringcolor = a.getcolor(r.styleable.countdownview_ringcolor, context.getresources().getcolor(r.color.coloraccent));
    mringwidth = a.getfloat(r.styleable.countdownview_ringwidth, 40);
    mringprogesstextsize = a.getdimensionpixelsize(r.styleable.countdownview_progresstextsize, displayutil.sp2px(context, 20));
    mprogesstextcolor = a.getcolor(r.styleable.countdownview_progresstextcolor, context.getresources().getcolor(r.color.coloraccent));
    mcountdowntime = a.getinteger(r.styleable.countdownview_countdowntime, 10);
    a.recycle();
    mpaint = new paint(paint.anti_alias_flag);
    mpaint.setantialias(true);
    this.setwillnotdraw(false);
  }

  public void setcountdowntime(int mcountdowntime) {
    this.mcountdowntime = mcountdowntime;
  }

  @override
  protected void onlayout(boolean changed, int left, int top, int right, int bottom) {
    super.onlayout(changed, left, top, right, bottom);
    mwidth = getmeasuredwidth();
    mheight = getmeasuredheight();
    mrectf = new rectf(0 + mringwidth / 2, 0 + mringwidth / 2,
        mwidth - mringwidth / 2, mheight - mringwidth / 2);
  }

  @override
  protected void ondraw(canvas canvas) {
    super.ondraw(canvas);
    /**
     *圆环
     */
    //颜色
    mpaint.setcolor(mringcolor);
    //空心
    mpaint.setstyle(paint.style.stroke);
    //宽度
    mpaint.setstrokewidth(mringwidth);
    canvas.drawarc(mrectf, -90, mcurrentprogress - 360, false, mpaint);
    //绘制文本
    paint textpaint = new paint();
    textpaint.setantialias(true);
    textpaint.settextalign(paint.align.center);
    string text = mcountdowntime - (int) (mcurrentprogress / 360f * mcountdowntime) + "";
    textpaint.settextsize(mringprogesstextsize);
    textpaint.setcolor(mprogesstextcolor);

    //文字居中显示
    paint.fontmetricsint fontmetrics = textpaint.getfontmetricsint();
    int baseline = (int) ((mrectf.bottom + mrectf.top - fontmetrics.bottom - fontmetrics.top) / 2);
    canvas.drawtext(text, mrectf.centerx(), baseline, textpaint);
  }

  private valueanimator getvala(long countdowntime) {
    valueanimator valueanimator = valueanimator.offloat(0, 100);
    valueanimator.setduration(countdowntime);
    valueanimator.setinterpolator(new linearinterpolator());
    valueanimator.setrepeatcount(0);
    return valueanimator;
  }
  /**
   * 开始倒计时
   */
  public void startcountdown() {
    setclickable(false);
    valueanimator valueanimator = getvala(mcountdowntime * 1000);
    valueanimator.addupdatelistener(new valueanimator.animatorupdatelistener() {
      @override
      public void onanimationupdate(valueanimator animation) {
        float i = float.valueof(string.valueof(animation.getanimatedvalue()));
        mcurrentprogress = (int) (360 * (i / 100f));
        invalidate();
      }
    });
    valueanimator.start();
    valueanimator.addlistener(new animatorlisteneradapter() {
      @override
      public void onanimationend(animator animation) {
        super.onanimationend(animation);
        //倒计时结束回调
        if (mlistener != null) {
          mlistener.countdownfinished();
        }
        setclickable(true);
      }

    });
  }
  public void setaddcountdownlistener(oncountdownfinishlistener mlistener) {
    this.mlistener = mlistener;
  }
  public interface oncountdownfinishlistener {
    void countdownfinished();
  }

}

<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context="com.example.circulardemo.mainactivity">

  <com.example.circulardemo.countdownview
    android:id="@+id/cdv"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:layout_centervertical="true"
    android:layout_centerhorizontal="true" />

</relativelayout>

import android.os.bundle;
import android.support.v7.app.appcompatactivity;

public class mainactivity extends appcompatactivity {

  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.activity_main);
    countdownview countdownview = (countdownview) findviewbyid(r.id.cdv);
    //启动
    countdownview.startcountdown();

    countdownview.setaddcountdownlistener(new countdownview.oncountdownfinishlistener() {
      @override
      public void countdownfinished() {
        toast.maketext(mainactivity.this, "倒计时结束", toast.length_short).show();
      }
    });
  }


}