参数degree是手机旋转的角度，通过系统方法可得到；animation是否需要动画。该View作为一个控件使用，需要在程序中通过调用setOrientation()方法，来使其产生作用。
<span style="font-family:Arial;font-size:18px;"><span style="font-size:18px;"> public class RotatelView extends View { private static final int ANIMATION_SPEED = 270; private int mCurrentDegree = 0; // [0, 359] private int mStartDegree = 0; private int mTargetDegree = 0; private boolean mClockwise = false; private boolean mEnableAnimation = true; private long mAnimationStartTime = 0; private long mAnimationEndTime = 0; public void setOrientation(int degree, boolean animation) { mEnableAnimation = animation; // make sure in the range of [0, 359] degree = degree >= 0 ? degree % 360 : degree % 360 + 360; if (degree == mTargetDegree) return; mTargetDegree = degree; if (mEnableAnimation) { mStartDegree = mCurrentDegree; mAnimationStartTime = AnimationUtils.currentAnimationTimeMillis(); int diff = mTargetDegree - mCurrentDegree; diff = diff >= 0 ? diff : 360 + diff; // make it in range [0, 359] // Make it in range [-179, 180]. That's the shorted distance between the // two angles diff = diff > 180 ? diff - 360 : diff; mClockwise = diff >= 0; mAnimationEndTime = mAnimationStartTime + Math.abs(diff) * 1000 / ANIMATION_SPEED; } else { mCurrentDegree = mTargetDegree; } invalidate(); } @Override protected void onDraw(Canvas canvas) { if (mCurrentDegree != mTargetDegree) { long time = AnimationUtils.currentAnimationTimeMillis(); if (time < mAnimationEndTime) { int deltaTime = (int) (time - mAnimationStartTime); int degree = mStartDegree + ANIMATION_SPEED * (mClockwise ? deltaTime : -deltaTime) / 1000; degree = degree >= 0 ? degree % 360 : degree % 360 + 360; mCurrentDegree = degree; invalidate(); } else { mCurrentDegree = mTargetDegree; } } canvas.rotate((float) -mCurrentDegree); super.onDraw(canvas); } }来源：修改相机中的缩放图，使其能够平滑旋转。
