Android 实现圆形倒计时进度

要在Android上实现圆形倒计时进度，可以使用自定义View和计时器来实现。下面是实现的步骤：

1. 创建一个自定义的View类，继承自View，用于绘制圆形进度。
2. 在自定义View类中添加一个计时器，用于更新倒计时的进度。
3. 在onDraw方法中绘制圆形进度条，可以使用Canvas和Paint类来实现。
4. 在计时器中更新倒计时的进度，并调用invalidate方法来触发View的重绘。

下面是一个简单的示例代码：

public class CountdownCircleView extends View {
    private Paint mPaint;
    private int mProgress;
    private CountDownTimer mCountDownTimer;

    public CountdownCircleView(Context context) {
        super(context);
        init();
    }

    public CountdownCircleView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(10);
        mPaint.setColor(Color.BLUE);
        mProgress = 100;

        mCountDownTimer = new CountDownTimer(60000, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                mProgress = (int) (millisUntilFinished / 1000);
                invalidate();
            }

            @Override
            public void onFinish() {
                mProgress = 0;
                invalidate();
            }
        };
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        int centerX = getWidth() / 2;
        int centerY = getHeight() / 2;
        int radius = Math.min(centerX, centerY) - mPaint.getStrokeWidth() / 2;

        RectF rectF = new RectF(centerX - radius, centerY - radius, centerX + radius, centerY + radius);
        float sweepAngle = 360f * mProgress / 60;
        canvas.drawArc(rectF, -90, sweepAngle, false, mPaint);
    }

    public void startCountdown() {
        mCountDownTimer.start();
    }
}

使用方式：

CountdownCircleView countdownView = findViewById(R.id.countdown_view);
countdownView.startCountdown();