環形ProgressBar的旋轉動畫效果

要實現環形ProgressBar的旋轉動畫效果，可以通過自定義View來繪制環形ProgressBar，并使用屬性動畫來實現旋轉效果。

首先，創建一個繼承自View的自定義View類，重寫onDraw方法來繪制環形ProgressBar：

public class CircularProgressView extends View {

    private Paint paint;
    private RectF rect;
    private int progress = 0;

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

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

    public CircularProgressView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        paint = new Paint();
        paint.setColor(Color.BLUE);
        paint.setStrokeWidth(20);
        paint.setStyle(Paint.Style.STROKE);
        paint.setAntiAlias(true);

        rect = new RectF();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        int centerX = getWidth() / 2;
        int centerY = getHeight() / 2;
        int radius = Math.min(centerX, centerY) - 10;

        rect.set(centerX - radius, centerY - radius, centerX + radius, centerY + radius);

        float angle = 360 * progress / 100;

        canvas.drawArc(rect, -90, angle, false, paint);
    }

    public void setProgress(int progress) {
        this.progress = progress;
        invalidate();
    }
}

然后，在Activity或Fragment中使用屬性動畫來實現旋轉效果：

ObjectAnimator animator = ObjectAnimator.ofInt(circularProgressView, "progress", 0, 100);
animator.setDuration(2000);
animator.setInterpolator(new LinearInterpolator());
animator.setRepeatCount(ObjectAnimator.INFINITE);
animator.setRepeatMode(ObjectAnimator.RESTART);
animator.start();

這樣就可以實現環形ProgressBar的旋轉動畫效果了。可以根據具體需求調整旋轉的速度、方向和顏色等屬性。