Android 绘制rotate控件/图像

       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。