我正在尝试旋转此图像上的一个透明PNG.数字部分是我想要旋转的部分.我能够做到这一点,但这不是我想要实现的目标
http://i48.tinypic.com/25exzle.png
我想像真正的密码锁一样旋转数字.因此,用户将触摸并将他们的手指移动一圈.我在触摸/移动事件中看到了不太精确的图像旋转,但它们还不够.
这是我目前的代码
public boolean onTouch(View v,MotionEvent event) {
double r=Math.atan2(event.getX()-lockNumbers.getWidth(),lockNumbers.getHeight()-event.getY());
int rotation=(int)Math.toDegrees(r);
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
x=event.getX();
y=event.getY();
updateRotation(rotation);
break;
case MotionEvent.ACTION_UP:
break;
}//switch
return true;
}//onTouch
private void updateRotation(double rot){
float newRot=new Float(rot);
Bitmap bitmap=BitmapFactory.decodeResource(getResources(),R.drawable.numbers);
Matrix matrix=new Matrix();
matrix.postRotate(newRot,bitmap.getWidth(),bitmap.getHeight());
if(y>250){
Bitmap reDrawnBitmap=Bitmap.createBitmap(bitmap,bitmap.getHeight(),matrix,true);
lockNumbers.setImageBitmap(reDrawnBitmap);
}
else{
Bitmap reDrawnBitmap=Bitmap.createBitmap(bitmap,true);
lockNumbers.setImageBitmap(reDrawnBitmap);
}
}
由于矩阵参数,它也会在触摸时调整位图的大小.这不是理想的效果.
用户几乎需要用手指进入一个圆圈.
解决方法
将以下代码写入您的触摸事件.
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
// 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() - (dialerWidth / 2),dialerHeight - event.getY() - (dialerHeight / 2))] = true;
detector.onTouchEvent(event);
return true;
