public interface IRotateDetector {/*** handle rotation in onTouchEvent** @param event The motion event.* @return True if the event was handled, false otherwise.*/boolean onTouchEvent(MotionEvent event);/*** is the Gesture Rotate** @return true:rotating;false,otherwise*/boolean isRotating();
}复制代码
public class RotateGestureDetector implements IRotateDetector{private int mLastAngle = 0;//最后一次的角度值private IRotateListener mListener;//用来旋转的回调Listenerprivate boolean mIsRotate;//是否处于旋转//用来设置回调Listener的方法public void setRotateListener(IRotateListener listener) {this.mListener = listener;}//用来接收触摸事件@Overridepublic boolean onTouchEvent(MotionEvent event) {return doRotate(event);}//真正的计算手势操作所得到的角度值的方法，及回调调用。private boolean doRotate(MotionEvent ev) {if (ev.getPointerCount() != 2) {return false;}//Calculate the angle between the two fingersint pivotX = (int) (ev.getX(0) + ev.getX(1)) / 2;int pivotY = (int) (ev.getY(0) + ev.getY(1)) / 2;float deltaX = ev.getX(0) - ev.getX(1);float deltaY = ev.getY(0) - ev.getY(1);double radians = Math.atan(deltaY / deltaX);int degrees = (int) Math.round(Math.toDegrees(Math.atan2(deltaY,deltaX)));switch (ev.getActionMasked()) {case MotionEvent.ACTION_DOWN:mLastAngle = degrees;mIsRotate = false;break;case MotionEvent.ACTION_UP:mIsRotate = false;break;case MotionEvent.ACTION_POINTER_DOWN:mLastAngle = degrees;mIsRotate = false;break;case MotionEvent.ACTION_CANCEL:case MotionEvent.ACTION_POINTER_UP:mIsRotate = false;upRotate(pivotX, pivotY);mLastAngle = degrees;break;case MotionEvent.ACTION_MOVE:mIsRotate = true;int degreesValue = degrees - mLastAngle;if (degreesValue > 45) {//Going CCW across the boundaryrotate(-5, pivotX, pivotY);} else if (degreesValue < -45) {//Going CW across the boundaryrotate(5, pivotX, pivotY);} else {//Normal rotation, rotate the differencerotate(degreesValue, pivotX, pivotY);}//Save the current anglemLastAngle = degrees;break;}return true;}//回调的方法之一：控制图片根据手势的变化实时进行旋转private void rotate(int degree, int pivotX, int pivotY) {if (mListener != null) {mListener.rotate(degree, pivotX, pivotY);}}//回调的方法之一：最后某个手指放开后，控制图片自动回归到合适的位置。private void upRotate(int pivotX, int pivotY) {if (mListener != null) {mListener.upRotate(pivotX, pivotY);}}}复制代码
rotateGestureDetector.setRotateListener(new IRotateListener() {@Overridepublic void rotate(int degree, int pivotX, int pivotY) {//图片跟着手势进行旋转mSuppMatrix.postRotate(degree, pivotX, pivotY);//Post the rotation to the imagecheckAndDisplayMatrix();}@Overridepublic void upRotate(int pivotX, int pivotY) {//当手指头松开的时候，让图片自动更新到合适的位置。float[] v = new float[9];mSuppMatrix.getValues(v);// calculate the degree of rotationint angle = (int) Math.round(Math.toDegrees(Math.atan2(v[Matrix.MSKEW_Y], v[Matrix.MSCALE_X])));mRightAngleRunnable = new RightAngleRunnable(angle, pivotX, pivotY);photoView.post(mRightAngleRunnable);}
});复制代码
手指头松开手图片自动旋转到合适位置：
我们知道，前面图片跟着旋转，是获取到了(int degree, int pivotX, int pivotY)这三个值，然后让mSuppMatrix.postRotate(degree, pivotX, pivotY);那我们就当手指头松开的时候，获取到最终这个图片比原来变化了多少角度即可。然后根据这个当前最终图片的变化角度来进行适当的旋转，让其旋转到合适位置。
我们来具体看怎么实现的：
@Override
public void upRotate(int pivotX, int pivotY) {//当手指头松开的时候，让图片自动更新到合适的位置。float[] v = new float[9];mSuppMatrix.getValues(v);// calculate the degree of rotationint angle = (int) Math.round(Math.toDegrees(Math.atan2(v[Matrix.MSKEW_Y], v[Matrix.MSCALE_X])));mRightAngleRunnable = new RightAngleRunnable(angle, pivotX, pivotY);photoView.post(mRightAngleRunnable);
}复制代码
public class Matrix {public static final int MSCALE_X = 0; //!< use with getValues/setValuespublic static final int MSKEW_X = 1; //!< use with getValues/setValuespublic static final int MTRANS_X = 2; //!< use with getValues/setValuespublic static final int MSKEW_Y = 3; //!< use with getValues/setValuespublic static final int MSCALE_Y = 4; //!< use with getValues/setValuespublic static final int MTRANS_Y = 5; //!< use with getValues/setValuespublic static final int MPERSP_0 = 6; //!< use with getValues/setValuespublic static final int MPERSP_1 = 7; //!< use with getValues/setValuespublic static final int MPERSP_2 = 8; //!< use with getValues/setValues..................
}复制代码
然后我们再把获取到的角度和中心点，通过一个Runnable来进行图片最后的矫正：
mRightAngleRunnable = new RightAngleRunnable(angle, pivotX, pivotY);
photoView.post(mRightAngleRunnable);复制代码
