思路:

1.基于时间的显示映射。如:给定度数,显示圆弧,加上时序,即可有圆弧动画的效果

2.给定时序。用于驱动动画的一帧帧绘制

方案一、基于ObjectAnimator。动画运作时会调用degree对应set函数(基于放射调用),即setDegree。

ObjectAnimator ani=ObjectAnimator.ofInt(myView, "degree", 0,300);
ani.start();

注:1>混编后,默认会将setDegree混掉,导致找不到函数,故混编后这种机制会失效。解决方法是1.proguard中防止该段代码混编(具体方法百度) 2.使用方法二

     2>ObjectAnimator在3.0后才支持,可使用NineOldAndroids库,效果完全一样。

方案二、仍然基于ObjectAnimator。但基于回调,这种方法未用到反射,故混编时仍ok

ObjectAnimator ani=ObjectAnimator.ofInt(myView, new Prop(), 0,300);
ani.start();

class Prop extends Property<View, Integer> {
		
		public Prop() {
			// TODO Auto-generated constructor stub
			super(Integer.class, "kk");
		}
		
		@Override
		public void set(View object, Integer value) {
			// TODO Auto-generated method stub
			((MyView1)object).setDegree(value);
		}
		
		@Override
		public Integer get(View object) {
			// TODO Auto-generated method stub
			return null;
		}
	};

方案三、用animation提供时序。interpolatedTime为0~1,即时间的百分比。

Animation ani=new Animation() {
				@Override
				protected void applyTransformation(float interpolatedTime,
						Transformation t) {
					// TODO Auto-generated method stub
					myView.setDegree((int)(interpolatedTime*300f));
				}
			};
			ani.setDuration(3000);
			myView.startAnimation(ani);

//===========================================================================

自定义视图,setDegress可改变圆弧角度:

private class MyView1 extends ImageView {

		public int degree = 0;

		public MyView1(Context ct) {
			// TODO Auto-generated constructor stub
			super(ct);

		}
		
		@Override
		protected void onDraw(Canvas canvas) {
			// TODO Auto-generated method stub
			super.onDraw(canvas);

			Rect r = new Rect();
			getLocalVisibleRect(r);
			canvas.drawArc(new RectF(r), 0, degree, true, pt);
		}

		public void setDegree(int degree) {
			this.degree = degree;
			invalidate();
		}
	}

效果: