我有一个正在Fling旋转的轮子的ImageView。当旋转完成时,如何检测轮子的最终位置呢?基本上,类似于幸运转盘的轮子,结果取决于轮子停止的位置。
有没有一种方法可以检测Fling/旋转何时完成,然后获取最终角度?我想将该角度与圆形的4个象限之一相关联,并设置该结果。谢谢。下面是我的一些代码 //////////////////////////Gesture Detect /////////////////
有没有一种方法可以检测Fling/旋转何时完成,然后获取最终角度?我想将该角度与圆形的4个象限之一相关联,并设置该结果。谢谢。下面是我的一些代码 //////////////////////////Gesture Detect /////////////////
private class MyWheelOnTouchListener implements OnTouchListener {
private double startAngle;
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
rotateAnim(); // test
// reset the touched quadrants
for (int i = 0; i < quadrantTouched.length; i++) {
quadrantTouched[i] = false;
}
allowRotating = false;
startAngle = getAngle(event.getX(), event.getY());
break;
case MotionEvent.ACTION_MOVE:
double currentAngle = getAngle(event.getX(), event.getY());
rotateDialer((float) (startAngle - currentAngle));
startAngle = currentAngle;
break;
case MotionEvent.ACTION_UP:
allowRotating = true;
break;
}
// set the touched quadrant to true
quadrantTouched[getQuadrant(event.getX() - (wheelWidth / 2), wheelHeight - event.getY() - (wheelHeight / 2))] = true;
wheeldetector.onTouchEvent(event);
return true;
}
}
/**
* Simple implementation of a {@link SimpleOnGestureListener} for detecting a fling event.
*/
private class MyWheelGestureDetector extends SimpleOnGestureListener {
private double endAngle;
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
// get the quadrant of the start and the end of the fling
int q1 = getQuadrant(e1.getX() - (wheelWidth / 2), wheelHeight - e1.getY() - (wheelHeight / 2));
int q2 = getQuadrant(e2.getX() - (wheelWidth / 2), wheelHeight - e2.getY() - (wheelHeight / 2));
// the inversed rotations
if ((q1 == 2 && q2 == 2 && Math.abs(velocityX) < Math.abs(velocityY))
|| (q1 == 3 && q2 == 3)
|| (q1 == 1 && q2 == 3)
|| (q1 == 4 && q2 == 4 && Math.abs(velocityX) > Math.abs(velocityY))
|| ((q1 == 2 && q2 == 3) || (q1 == 3 && q2 == 2))
|| ((q1 == 3 && q2 == 4) || (q1 == 4 && q2 == 3))
|| (q1 == 2 && q2 == 4 && quadrantTouched[3])
|| (q1 == 4 && q2 == 2 && quadrantTouched[3])) {
wheel.post(new FlingWheelRunnable(-1 * (velocityX + velocityY)));
} else {
// the normal rotation
wheel.post(new FlingWheelRunnable(velocityX + velocityY));
}
endAngle = getAngle(e1.getX(), e2.getY());
return true;
}
}
/**
* A {@link Runnable} for animating the the dialer's fling.
*/
private class FlingWheelRunnable implements Runnable {
private float velocity;
public FlingWheelRunnable(float velocity) {
this.velocity = velocity;
}
@Override
public void run() {
if (Math.abs(velocity) > 5) { // original = 5
rotateDialer(velocity / 100); // original = 75
velocity /= 1.0666F; // original = 1.0666F
wheel.getRotation()); <-- maybe something like this, but not working??
// post this instance again
wheel.post(this);
}
}
}
/**
* @return The angle of the unit circle with the image view's center
*/
private double getAngle(double xTouch, double yTouch) {
double x = xTouch - (wheelWidth / 2d);
double y = wheelHeight - yTouch - (wheelHeight / 2d);
switch (getQuadrant(x, y)) {
case 1:
return Math.atan(y / x) * 180 / Math.PI;
case 2:
return 180 - Math.atan(y / x) * 180 / Math.PI;
case 3:
return 180 + (-1 * Math.atan(y / (x)) * 180 / Math.PI);
case 4:
return 360 + Math.atan(y / (x)) * 180 / Math.PI;
default:
return 0;
}
}
/**
* @return The selected quadrant.
*/
private static int getQuadrant(double x, double y) {
if (x >= 0) {
return y >= 0 ? 1 : 4;
} else {
return y >= 0 ? 2 : 3;
}
}
/**
* Rotate the wheel.
*
* @param degrees The degrees, the dialer should get rotated.
*/
private void rotateDialer(float degrees) {
matrix.postRotate(degrees, wheelWidth / 2, wheelHeight / 2);
wheel.setImageMatrix(matrix);
}