android实现圆环倒计时控件

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <!-- 倒计时控件属性 -->
 <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>

public class CountDownView extends View {
 //圆环颜色
 private int mRingColor;
 //圆环宽度
 private float mRingWidth;
 //圆环进度值文本大小
 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;
 ValueAnimator valueAnimator;
 /**
 * 监听事件
 */
 private OnCountDownListener mListener;
 public CountDownView(Context context) {
 this(context, null);
 }
 public CountDownView(Context context, @Nullable AttributeSet attrs) {
 this(context, attrs, 0);
 }
 public CountDownView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 // init();
 /**
 * 获取相关属性值
 */
 TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.CountDownView);
 mRingColor = typedArray.getColor(R.styleable.CountDownView_ringColor, context.getResources().getColor(R.color.colorAccent));
 mRingWidth = typedArray.getFloat(R.styleable.CountDownView_ringWidth, 40);
 mRingProgessTextSize = typedArray.getDimensionPixelSize(R.styleable.CountDownView_progressTextSize, 20);
 mProgessTextColor = typedArray.getColor(R.styleable.CountDownView_progressTextColor, context.getResources().getColor(R.color.colorAccent));
 mCountdownTime = typedArray.getInteger(R.styleable.CountDownView_countdownTime, 60);
 typedArray.recycle();
 mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
 mPaint.setAntiAlias(true);
 this.setWillNotDraw(false);
 }
 @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);
 }
 /**
 * 设置倒计时间 单位秒
 * @param mCountdownTime
 */
 public void setCountdownTime(int mCountdownTime) {
 this.mCountdownTime = mCountdownTime;
 invalidate();
 }
// public CountDownView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
// super(context, attrs, defStyleAttr, defStyleRes);
// }
 /**
 * 动画
 * @param countdownTime
 * @return
 */
 private ValueAnimator getValueAnimator(long countdownTime) {
 ValueAnimator valueAnimator = ValueAnimator.ofFloat(0, 100);
 valueAnimator.setDuration(countdownTime);
 valueAnimator.setInterpolator(new LinearInterpolator());
 valueAnimator.setRepeatCount(0);
 return valueAnimator;
 }
 @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);
 }
 /**
 * 开始倒计时
 */
 public void startCountDown() {
 valueAnimator = getValueAnimator(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();
 }
 }
 });
 }
 /**
 * 停止倒计时
 */
 public void stopCountDdwn(){
 valueAnimator.cancel();
 }
 public void setOnCountDownListener(OnCountDownListener mListener) {
 this.mListener = mListener;
 }
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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=".MainActivity">
 <demo.com.countdowndemo.CountDownView
 android:id="@+id/countDownView"
 android:layout_width="50dp"
 android:layout_height="50dp"
 app:countdownTime="5"
 app:ringWidth="2"
 app:layout_constraintBottom_toBottomOf="parent"
 app:layout_constraintLeft_toLeftOf="parent"
 app:layout_constraintRight_toRightOf="parent"
 app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

public class MainActivity extends AppCompatActivity {
 CountDownView countDownView;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 countDownView = findViewById(R.id.countDownView);
 countDownView.setOnCountDownListener(new OnCountDownListener() {
 @Override
 public void countDownFinished() {
 //倒计时结束
 //countDownView.setCountdownTime(10);
 Intent intent = new Intent(MainActivity.this, Main2Activity.class);
 startActivity(intent);
 }
 });
 countDownView.startCountDown();
 countDownView.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 countDownView.stopCountDdwn();
 Intent intent = new Intent(MainActivity.this, Main2Activity.class);
 startActivity(intent);
 }
 });
 }
}