menu.gif
实现思路：
1、根据思路可以自己确定到半径与圆心的每个按钮所在的x点，可根据数学公式求得y点
2、给按钮添加拖动手势UIPanGestureRecognizer,根据偏移量x计算出对应偏移弧线的距离，根据圆的运动轨迹赋值给按钮的x 并更新 y
3、结束拖动手势的时候计算偏移距离、根据是否划到下一个按钮的一半的width来实施动画更新按钮的center
实现细节:
已知圆心、半径与x值求y值：（x-a）^2 + (y - b)^ 2 = r^2。
用到的UIPanGestureRecognizer的三种状态:UIGestureRecognizerStateBegan\UIGestureRecognizerStateChanged\UIGestureRecognizerStateEnded
用UIPanGestureRecognizer的locationInView方法来确定当前点的位置
if(pgr.state==UIGestureRecognizerStateBegan){
self.endMove = NO;
self.beginPoint=[pgr locationInView:self];
}else if (pgr.state==UIGestureRecognizerStateChanged){
self.movePoint= [pgr locationInView:self];
self.moveX = sqrt(fabs(self.movePoint.x - self.beginPoint.x) * fabs(self.movePoint.x - self.beginPoint.x) + fabs(self.movePoint.y - self.beginPoint.y) * fabs(self.movePoint.y - self.beginPoint.y));
}
计算出偏移的x点后要根据起始点来判断用户是向左滑动还是向右滑动
if (self.movePoint.x>self.beginPoint.x) {
self.moveNum += self.moveX;
} else{
self.moveNum -= self.moveX;
}
之后判断判断是否超过了所有按钮所在的范围并赋值
if (self.moveNum > 0) {
self.moveNum = 0;
}
if (self.moveNum < -((SCREEN_WIDTH - 20 - subViewW)/(self.showBtnCount - 1)) * (self.subViewArray.count - self.showBtnCount)) {
self.moveNum = -((SCREEN_WIDTH - 20 - subViewW)/(self.showBtnCount - 1)) * (self.subViewArray.count - self.showBtnCount);
}
将偏移量赋值给x并更新y值
///中心点
CGFloat yy = 0.0;
CGFloat xx = 0.0;
CGFloat margin = 0.0;
///子视图x中点
UIView *view = self.subViewArray[0];
CGFloat subCenterX = view.frame.size.width / 2;
for (NSInteger i=0; i<self.subViewArray.count ;i++) {// 178,245
margin = i * ((SCREEN_WIDTH - 20 - view.frame.size.width)/(self.showBtnCount - 1));
xx = 10 + subCenterX + fabs(self.subViewX) + margin + self.moveNum;
yy = sqrt((self.radius - self.circleMargin / 2) * (self.radius - self.circleMargin / 2) - (xx - self.radius) * (xx - self.radius)) + self.radius;
if (xx >= self.radius - (self.radius - self.circleMargin / 2) && xx <= self.radius + (self.radius - self.circleMargin / 2)) {
UIButton *button=[self.subViewArray objectAtIndex:i];
NSLog(@"~~~~~~~%@",button);
if (self.isEndMove) {
[UIView animateWithDuration:0.3 animations:^{
button.center=CGPointMake(xx , yy);
}];
} else{
button.center=CGPointMake(xx , yy);
}
}
NSLog(@"xx:%f---------yy:%f",xx,yy);
}
原理大概就是这些
然后把项目中的效果直接做了简单的封装传了个demo，地址:https://github.com/xuuhan/HXCamberMenu
因为项目比较忙，暂时还没时间做完善，效果和功能还有着明显的限制，后续闲下来会进一步完善封装，希望同学们多多指教
