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();
}
});
}
}