*:first-child {
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a {
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a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }

h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
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text-decoration: none; }

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h1 {
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color: black; }

h2 {
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color: black; }

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h4 {
font-size: 16px; }

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padding-top: 0; }
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margin-top: 0;
padding-top: 0; }

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margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

dl {
padding: 0; }
dl dt {
font-size: 14px;
font-weight: bold;
font-style: italic;
padding: 0;
margin: 15px 0 5px; }
dl dt:first-child {
padding: 0; }
dl dt > :first-child {
margin-top: 0; }
dl dt > :last-child {
margin-bottom: 0; }
dl dd {
margin: 0 0 15px;
padding: 0 15px; }
dl dd > :first-child {
margin-top: 0; }
dl dd > :last-child {
margin-bottom: 0; }

blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

table {
padding: 0;border-collapse: collapse; }
table tr {
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background-color: white;
margin: 0;
padding: 0; }
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font-weight: bold;
border: 1px solid #cccccc;
margin: 0;
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table tr td {
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr th :first-child, table tr td :first-child {
margin-top: 0; }
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margin-bottom: 0; }

img {
max-width: 100%; }

span.frame {
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float: left; }
span.frame span span {
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color: #333333;
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display: block;
overflow: hidden;
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display: block;
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overflow: hidden;
float: left; }
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overflow: hidden;
margin: 13px auto 0;
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code, tt {
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pre {
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font-size: 13px;
line-height: 19px;
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sup {
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body {
width: 854px;
margin:0 auto;
}
}
@media print {
table, pre {
page-break-inside: avoid;
}
pre {
word-wrap: break-word;
}
}
-->

05-QQ粘性布局

整体思路径:

手指移动,按钮跟着移动.按钮跟着手指移动.移动时底部有一个圆.

根据上面的大圆按钮拖动的距离,小圆的半径在变小.移动时中间有一块不规则的填充区域.

手指移动超出一定的范围,填充效果消失,当手指松开时.判断当前大圆距离与小圆之间的距离.

如果小于60就让大圆回来原来的位置.下次拖动时,同样具有填充效果.

如果大于60,手指松开时,播放一个动画.动画完成时, 删除动画按钮.

实现步骤:

1.自定义大圆控件(UIButton)可以显示背景图片和文字

按钮定义的时候要在初始方法中,把它的基本属性设置好.在开始加载的时候设置.

基本属性包括颜色,圆角,文字颜色,大小.

实现代码:

self.backgroundColor = [UIColor redColor];

self.layer.cornerRadius = self.bounds.size.width * 0.5;     self.titleLabel.font = [UIFont systemFontOfSize:12];

[self setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];

2.让大圆控件随着手指移动而移动

添加手势.同样也是在初始化方法当中进行设置.

注意不能根据形变修改大圆的位置,只能通过center,因为全程都需要用到中心点计算.

tansform并没有修改center,它修改的是Frame.

添加手势代码为:

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];

[self addGestureRecognizer:pan];

手势实现方法为:

CGPoint transP = [pan translationInView:self]; CGPoint center = self.center;

center.x += transP.x;

center.y +=transP.y;

self.center = center;

注意要做复位,相对于上一次.

[pan setTranslation:CGPointZero inView:self];

3.在拖动的时候,添加一个小圆控件在原来大圆控件的位置

在初始化方法中添加小圆

注意:添加小圆时不能够直接添加在当前按钮上,因为按钮是可以移动的,如果直接添加在按钮,它会跟着按钮一起移动.

所以把小圆添加到按钮父控件当中.添加时注意,要把小圆添加到按钮底部.不然会把按钮给盖起来.

UIView *smallCircle = [[UIView alloc] init];

smallCircle.frame = self.frame;

smallCircle.layer.cornerRadius = self.layer.cornerRadius;

smallCircle.backgroundColor = self.backgroundColor;     self.smallCircle = smallCircle;

[self.superview insertSubview:smallCircle belowSubview:self];

当手指拖动大圆时,小圆的半径会根据拖动的距离进行减小.所以要计算出两个圆之间的距

离. 计算完毕后.让小圆的原始半径每次都减去一个距离比例.重新设置尺寸大小和小圆的半径.

计算两个圆之间距离是一个功能单独抽出来.

方法为:

- (CGFloat)distanceWithSmallCircle:(UIView *)smallView bigCircle (UIView *)bigCircle{

X轴的偏移量

CGFloat offsetX = bigCircle.center.x - smallView.center.x;

Y轴的偏移量

CGFloat offsetY = bigCircle.center.y - smallView.center.y;

CGFloat distance = sqrt(offsetX * offsetX + offsetY * offsetY);     return distance;

}

在手指拖动方法计算两个圆之间的距离, 根据拖动的距离让小圆的半径增大减小.

实现代码为:

CGFloat distance = [self distanceWithSmallCircle:self.smallCircle bigCircle:self];

取出小圆的半径

注意这里是取出小圆最初的宽度,由于每次拖动的时候都会去修改小圆的宽 .所以这里不能直接用小圆的宽度

这里用的是大圆的宽度,开始小圆和大圆的宽度是一样的.

大圆在移动时,大圆的宽高没有发现变化,所以可以拿到大圆的宽高

CGFloat smallR = self.bounds.size.width * 0.5;

让小圆的半径每次减去一个距离比例

smallR = smallR - distance / 10.0;

每次移动时,重新设置小圆的宽高

self.smallCircle.bounds = CGRectMake(0, 0, smallR * 2, smallR * 2);

重新设置小圆的圆角

self.smallCircle.layer.cornerRadius = smallR;

4.添加粘性效果

中间的粘性效果其实就是一块填充区域.只要把这个填充区域的路径给求出来就行了.

中间的路径通过确定6个点.把这些点连接出来就行.

求点为:

x1,y1分别是小圆的圆心

x2,y2分别是大圆的圆心

r1代表小圆的半径

r2代表大圆的半径

d是两个圆之间的距离

y轴的偏移量 / 两个圆之间的距离

cosθ = (y2 - y1) / d;

x轴的偏移量 / 两个圆之间的距离

sinθ = (x2 - x1) / d;

已知一个角,一个斜边

角的邻边 = 斜边 * cosθ

角的对边 = 斜边 * sinθ

CGPoint pointA = CGPointMake(x1 - r1 * cosθ, y1 + r1 * sinθ);

CGPoint pointB = CGPointMake(x1 + r1 * cosθ, y1 - r1 * sinθ);

CGPoint pointC = CGPointMake(x2 + r2 * cosθ, y2 - r2 * sinθ);

CGPoint pointD = CGPointMake(x2 - r2 * cosθ, y2 + r2 * sinθ);

CGPoint pointO = CGPointMake(pointA.x + d * 0.5 * sinθ, pointA.y + d * 0.5 * cosθ);

CGPoint pointP = CGPointMake(pointB.x + d * 0.5 * sinθ, pointB.y + d * 0.5 * cosθ);

创建路径,把这些点连接到一起

UIBezierPath *path = [UIBezierPath bezierPath];

AB

[path moveToPoint:pointA];

[path addLineToPoint:pointB];

BC(曲线)

[path addQuadCurveToPoint:pointC controlPoint:pointP];

CD

[path addLineToPoint:pointD];

DA(曲线)

[path addQuadCurveToPoint:pointA controlPoint:pointO];

以上是根据两个圆求出不规则的矩形

求出路径后,要把路径填充起来.但是不能够直接给填充到当前的按钮之上.按钮是可以拖动的.

绘制东西,当超出它的范围以外就不会再绘制.

所以要把路径添加到按钮的子控件当中, 但是当前是一个路径,是不能够直接添加到子控件当中的.

可能过形状图层添加.

形状图层会根据一个路径生成一个形状.把这个形状添加到当前控件的图片父层就可以了.    添加时需要注意:

形状图层之有一个,所以不能够在手指拖动方法当中添加.由于当手指拖动的距离超过某个范围后,形状图片会被移除.

下一次再去移动时, 还会有填充的路径.所以把创建形状图层搞成一个懒加载的形式. 如果发现下一次被删除时,再重新创建.

形式为:

-(CAShapeLayer *)shap{ if (_shap == nil) {

    创建形状图层

    CAShapeLayer *shap = [CAShapeLayer layer];

    设置形状图层的填充颜

    shap.fillColor = [UIColor redColor].CGColor;

    self.shap = shap;

    把形状图层添加到当前按钮的父层当中.

    [self.superview.layer insertSublayer:shap atIndex:0];

    _shap = shap;

    }

return _shap;

}

在手指移动方法当中,给形状图层赋值路径就可以了.

5.粘性业务逻辑处理

在手指移动方法判断两个圆之间的距离, 如果发现两个圆之间的距离超过60时

让底部的小圆隐藏.把路径移除

当小圆显示的时候才绘制填充路径

if (self.smallCircle.hidden == NO) {

UIBezierPath *path = [self pathWithSmallCircle:self.smallCircle bigCircle:self];

self.shap.path = path.CGPath; }

当两个圆之间的距离超过60时.

if(distance > 60){

移除填充路径

[self.shap removeFromSuperlayer];

让底部的小圆隐匿

self.smallCircle.hidden = YES;

}

6.手指停止拖动业务逻辑

移动后手指松开时判断两个圆之间的距离,如果两个圆之间的距离小于60时,让大圆复位.小圆显示.

手指松开时,如果两个圆之间的距离大于60时.播放一个动画.动画播放完毕时.把当前按钮从父控件当中移除.

播放一个动画.

创建一个UIImageView,尺 寸和当前按钮一样大.

UIImageView *imageV = [[UIImageView alloc] initWithFrame:self.bounds];

创建动画图

NSMutableArray *imageArray = [NSMutableArray array];

for (int i = 0; i < 8 ; i++) {

NSString *imageName = [NSString stringWithFormat:@"%d",i+1];    UIImage *image = [UIImage imageNamed:imageName];

[imageArray addObject:image];

}

设置动画图片数组

imageV.animationImages = imageArray;

设置动画执行时长

imageV.animationDuration = 1;

开始动画

[imageV startAnimating];

把UIImageView添加到当前按钮上

[self addSubview:imageV];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

[self removeFromSuperview]; });

注意:

在控制器加载完毕后,要取消Autoresizing转自动布局

不然会出现按钮回原位的情况.

self.view.translatesAutoresizingMaskIntoConstraints = NO;