代码块

attr.xml 控件需要用到的属性：

CountDownView.java

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, DisplayUtils.sp2px(context, 20));  mProgessTextColor = a.getColor(R.styleable.CountDownView_progressTextColor, context.getResources().getColor(R.color.colorAccent));  mCountdownTime = a.getInteger(R.styleable.CountDownView_countdownTime, 60);  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(); }}

MainActivity.java

package com.ouyuan.demo.myapplication;import android.animation.ValueAnimator;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends AppCompatActivity { CountDownView cdv; TextView textView; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  cdv = (CountDownView) findViewById(R.id.countDownView);  cdv.setAddCountDownListener(new CountDownView.OnCountDownFinishListener() {   @Override   public void countDownFinished() {    Toast.makeText(MainActivity.this, "倒计时结束", Toast.LENGTH_SHORT).show();   }  });  cdv.setOnClickListener(new View.OnClickListener() {   @Override   public void onClick(View v) {    cdv.startCountDown();   }  }); }}