ios类似于qq账号信息里的一个动画效果

// 屏幕的宽度

 CGFloat width = [UIScreen mainScreen].bounds.size.width;

 // 圆半径

 floatr =2* width / sqrt(3);

 // 画曲线

 UIColor *color = [UIColor redColor];

 [color set];

 UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(0,0) radius:r startAngle:M_PI /2endAngle:M_PI /6clockwise:NO];

 path.lineWidth =1.0;

 path.lineCapStyle = kCGLineCapRound;

 path.lineJoinStyle = kCGLineJoinRound;

 [path stroke];

// 放图片

 for(inti =0; i<4; i++) {

  // 一共四个按钮 从左到右index分别为0，1，2，3

  UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

  button.frame = [self getButtonFrame:i];

  button.tag = i +1;

  [button addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];

  [button setImage:[UIImage imageNamed:[NSString stringWithFormat:@"%d",i +1]] forState:UIControlStateNormal];

  // 设置按钮为圆

  button.layer.cornerRadius =25;

  button.layer.borderColor = [UIColor greenColor].CGColor;

  button.layer.masksToBounds = YES;

  button.layer.borderWidth =2.0f;

  [self addSubview:button];

 }

 // 根据Index确定按钮的坐标

 - (CGRect)getButtonFrame: (int) index {

 floatradians = M_PI * (7.5+15* index) /180;

 CGFloat width = [UIScreen mainScreen].bounds.size.width;

 floatr =2* width / sqrt(3);

 CGRect frame = CGRectMake(sin(radians) * r, cos(radians) * r,50,50);

 frame.origin.x = frame.origin.x -25;

 frame.origin.y = frame.origin.y -25;

 returnframe;

 }

self.head = [[UIImageView alloc] initWithFrame:[self getButtonFrame:0]];

self.head.image = [UIImage imageNamed:@"myHead"];

self.head.layer.borderColor = [UIColor greenColor].CGColor;

self.head.layer.masksToBounds = YES;

self.head.layer.cornerRadius =25;

self.head.layer.borderWidth =2.0f;

[self addSubview:self.head];

// 按钮点击事件

- (void)buttonClick:(UIButton *)button {

 // 原来图片所在按钮的index

 intpreIndex = [self getPreviousIndexByFrame:self.head.frame];

 intbuttonIndex = (int)button.tag -1;

 // 点击图片所在按钮 不做任何操作

 if(preIndex == buttonIndex) {

  return;

 }

 CGFloat width = [UIScreen mainScreen].bounds.size.width;

 floatr =2* width / sqrt(3);

 //加入动画效果

 CALayer *transitionLayer = [[CALayer alloc] init];

 //显式事务默认开启动画效果,kCFBooleanTrue关闭 保证begin和commit 之间的属性修改同时进行

 transitionLayer.contents = self.head.layer.contents;

 transitionLayer.borderColor = [UIColor greenColor].CGColor;

 transitionLayer.masksToBounds = YES;

 transitionLayer.cornerRadius =25;

 transitionLayer.borderWidth =2.0f;

 transitionLayer.frame = self.head.frame;

 transitionLayer.backgroundColor=[UIColor blueColor].CGColor;

 [self.layer addSublayer:transitionLayer];

 self.head.hidden = YES;

 UIBezierPath *movePath;

 //路径曲线 贝塞尔曲线

 if(buttonIndex > preIndex) {

  // 向上滑 逆时针

  movePath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(0,0) radius:r startAngle:[self getAnticlockwiseByIndex:preIndex] endAngle:[self getAnticlockwiseByIndex:buttonIndex] clockwise:NO];

  [movePath moveToPoint:transitionLayer.position];

 }else{

  // 向下滑 顺时针

  movePath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(0,0) radius:r startAngle:[self getClockwiseAngleByIndex:preIndex] endAngle:[self getClockwiseAngleByIndex:buttonIndex] clockwise:YES];

  [movePath moveToPoint:transitionLayer.position];

 }

 //关键帧动画效果

 CAKeyframeAnimation *positionAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];

 // 动画轨迹

 positionAnimation.path = movePath.CGPath;

 // 动画完成之后是否删除动画效果

 positionAnimation.removedOnCompletion = NO;

 // 设置开始的时间

 positionAnimation.beginTime = CACurrentMediaTime();

 CGFloat time =0.7;

 if(labs(buttonIndex - preIndex) >1) {

  time =0.4* labs(buttonIndex - preIndex);

 }

 //动画总时间

 positionAnimation.duration = time;

 // 动画的方式 淡入淡出

 positionAnimation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];

 // 执行完之后保存最新的状态

 positionAnimation.fillMode = kCAFillModeForwards;

 // 动画完成之后，是否回到原来的地方

 positionAnimation.autoreverses= NO;

 [transitionLayer addAnimation:positionAnimation forKey:@"opacity"];

 [CATransaction setCompletionBlock:^{

  [NSThread sleepForTimeInterval:time];

  self.head.hidden = NO;

  self.head.frame = button.frame;

  [transitionLayer removeFromSuperlayer];

 }];

}

// 根据Index获得顺时针的弧度

- (float)getAnticlockwiseByIndex: (NSInteger)index {

 returnM_PI * (0.5- (7.5+15* index) /180);

}

// 根据Index获得逆时针的弧度

- (float)getClockwiseAngleByIndex: (NSInteger)index {

 index =3- index;

 returnM_PI * (30+7.5+15* index) /180;

}