Core Animation一些Demo总结 （动态切换图片、大转盘、图片折叠、进度条等动画效果）

前一篇总结了core animation的一些基础知识，这一篇主要是core animation 的一些应用，涉及到cashapelayer、careplicatorlayer等图层的知识。

先看效果图：

1、切换图片：

2、彩票转盘

3、图片折叠

4、进度条旋转

5、粒子效果

一、切换图片

看起来很复杂的动画，通过少量的计算和编码就可以简单的实现。要做到这一步，必须是需要研究ios开发中的core animation和core graphics框架的。日常工作中，对于很多东西不求甚解，只是拿过来用，甚至都不研究、封装一下别人代码，这种做法是很不好的。我喜欢自己造*，*造多了，开发经验与思维也就提升上去了。

这个动画实现是比较简单的，利用了cabasicanimation、cakeyframeanimation和caanimationgroup。看似是两张图片各自有着自己不同的动画，实际不过是一个动画方法，其平移方向与旋转角度的不同。

我是用了cabasicanimation设置了view的zposition值，cakeyframeanimation对象设计了图片的位移与旋转动画，然后将之放到caanimationgroup对象里面，开始动画。

这里有一个注意点，那就是core animation设置的动画位移、旋转、缩放都只是一个假象，实际上的view该怎么还是怎么样，并未真正有过变化。所以，在动画结束后，想要正确的效果，那么需要设置view的zposition值，这个值越大，view越在前面（z轴方向上的“前面”）。

代码：

#import "viewcontroller.h"
@interface viewcontroller ()
@property (nonatomic, strong) nsmutablearray *images;
@property (nonatomic, assign) int currentindex;
@property (weak, nonatomic) iboutlet uiimageview *currentimageview;
@property (weak, nonatomic) iboutlet uiimageview *behindimageview;
@end
@implementation viewcontroller

- (nsmutablearray *)images
{
if (_images == nil) {
_images = [nsmutablearray array];

for (int i = 1; i <= 7; i++) {
uiimage *image = [uiimage imagenamed: [nsstring stringwithformat:@"%d",i]];
[_images addobject:image];
}
}
return _images;
}
- (void)viewdidload
{
[super viewdidload];

self.currentindex = 0;
self.currentimageview.image = self.images[_currentindex];
}
- (void)addanimatewithpoint:(cgpoint )point angle:(cgfloat)angle fromz:(cgfloat)fromz toz:(cgfloat)toz view:(uiview *)view
{
cabasicanimation *zposition = [[cabasicanimation alloc] init];
zposition.keypath = @"zposition";
zposition.fromvalue = @(fromz);
zposition.tovalue = @(toz);
zposition.duration = 1.2;
cakeyframeanimation *rotation = [[cakeyframeanimation alloc] init];
rotation.keypath = @"transform.rotation";
rotation.values = @[@(0), @(angle), @(0)];
rotation.duration = 2;
rotation.timingfunctions = @[
[camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout],
[camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout]];
cakeyframeanimation *position = [[cakeyframeanimation alloc] init];
position.keypath = @"position";
// cgpointmake(110, -20)
position.values = @[
[nsvalue valuewithcgpoint:cgpointzero],
[nsvalue valuewithcgpoint:point],
[nsvalue valuewithcgpoint:cgpointzero]
];
position.timingfunctions = @[
[camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout],
[camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout]
];
position.additive = yes;
position.duration = 1.2;
caanimationgroup *animategroup = [[caanimationgroup alloc] init];
animategroup.animations = @[zposition, rotation, position];
// animategroup.begintime = 0.5;
animategroup.delegate = self;
animategroup.duration = 1.2;
[animategroup setvalue:view forkey:@"view"];
[view.layer addanimation:animategroup forkey:nil]; 
view.layer.zposition = toz;

}
- (void)animationdidstop:(caanimation *)anim finished:(bool)flag
{
caanimationgroup *group = [anim valueforkey:@"view"];
if (group != nil) {
self.currentimageview.image = self.images[_currentindex];
self.currentimageview.layer.zposition = 1;
self.behindimageview.image = nil;
self.behindimageview.layer.zposition = -1;
}
}
- (ibaction)previous:(id)sender {
self.currentindex = (self.currentindex + 1) % self.images.count;
self.behindimageview.image = self.images[_currentindex];

[self addanimatewithpoint:cgpointmake(-90, 20) angle:0.15 fromz:-1 toz:1 view:self.behindimageview];
[self addanimatewithpoint:cgpointmake(90, -20) angle:-0.15 fromz:1 toz:-1 view:self.currentimageview];
}
- (ibaction)next:(id)sender {
self.currentindex = (self.currentindex + 6) % self.images.count;
self.behindimageview.image = self.images[_currentindex];
[self addanimatewithpoint:cgpointmake(-90, 20) angle:-0.15 fromz:-1 toz:1 view:self.behindimageview];
[self addanimatewithpoint:cgpointmake(90, -20) angle:0.15 fromz:1 toz:-1 view:self.currentimageview];
}
@end

二、彩票转盘

这个动画的实现主要难点在于button的摆放，只要摆放好button，其他就是简单的添加动画的一个过程。

12个星座，那么需要12个button。在摆放它们的时候，我是将一个个button的anchorpoint设置为(0.5, 1)，将button的position设置为中心圆的圆心，然后设置transform来旋转它们，是的达到围绕一个圆摆放的目的。

需要知道的是，一般来说，控件的anchorpoint就是控件的中心点，所以在我们做旋转、平移等操作的时候，也就是在围绕中心点的一系列操作。但是，很多时候，只是围绕中心点来设置动画的话，会很复杂，calayer提供了一个anchorpoint属性，可以让我们*的改变其数值，从而实现比较复杂的动画。

还有就是button的点击事件，事实上由于一个扇形区域是上边大，下边小，要是不做相应的限制，当用户点击下面的区域时，很可能不是选中当前的button，因此要做一定的限制。这里我是自定义了一个button，在里面重写了hittest: wwthevent: 方法，这个方法可以设置你所要监听事件的区域范围。

代码：

#import "zywheelview.h"
#define zyimagew 40
#define zyimageh 46
@interface zybutton : uibutton
@end
@implementation zybutton

/**
* 重写此方法，截取button的点击
*
*/
- (uiview *)hittest:(cgpoint)point withevent:(uievent *)event
{
cgfloat btnw = self.bounds.size.width;
cgfloat btnh = self.bounds.size.height;
cgfloat x = 0;
cgfloat y = btnh / 2;
cgfloat w = btnw;
cgfloat h = y;
cgrect rect = cgrectmake(x, y, w, h);
if (cgrectcontainspoint(rect, point)) {
return nil;
}else{
return [super hittest:point withevent:event];
}
}
- (cgrect)imagerectforcontentrect:(cgrect)contentrect
{
cgfloat imagex = (contentrect.size.width - zyimagew ) * 0.5;
cgfloat imagey = 18;
return cgrectmake(imagex, imagey, zyimagew, zyimageh);
}
- (void)sethighlighted:(bool)highlighted
{ 
}
@end
@interface zywheelview ()
@property (weak, nonatomic) iboutlet uiimageview *wheelview;

@property (nonatomic, weak) uibutton *lastselectedbtn;

@property (nonatomic, strong) cadisplaylink *timer;
@end
@implementation zywheelview
+ (instancetype)wheelview
{
return [[[nsbundle mainbundle] loadnibnamed:@"zywheelview" owner:nil options:nil] lastobject];
}
- (void)awakefromnib
{
self.wheelview.userinteractionenabled = yes;
cgfloat angle = 2 * m_pi / 12.0;

uiimage *normalimage = [uiimage imagenamed:@"luckyastrology"];
uiimage *selectedimage = [uiimage imagenamed:@"luckyastrologypressed"];
for (int bi = 0; bi < 12; bi++) {
zybutton *btn = [[zybutton alloc] init];
[btn setbackgroundimage:[uiimage imagenamed:@"luckyrototeselected"] forstate:uicontrolstateselected];
// 切割图片,将切割好的图片设置到按钮上
// cgimage中rect是当做像素来使用
// uikit 中是点坐标系
// 坐标系的特点:如果在非retain屏上 1个点等于1个像素
// 在retain屏上1个点等于2个像素
cgfloat imageh = zyimageh * [uiscreen mainscreen].scale;
cgfloat imagew = zyimagew * [uiscreen mainscreen].scale;
cgfloat imagey = 0;
cgfloat imagex = bi * imagew;
cgrect rect = cgrectmake(imagex, imagey, imagew, imageh);
cgimageref normalref = cgimagecreatewithimageinrect(normalimage.cgimage, rect);
cgimageref selectedref = cgimagecreatewithimageinrect(selectedimage.cgimage, rect);
[btn setimage:[uiimage imagewithcgimage:normalref] forstate:uicontrolstatenormal];
[btn setimage:[uiimage imagewithcgimage:selectedref] forstate:uicontrolstateselected];
btn.bounds = cgrectmake(0, 0, 58, 143);
btn.layer.anchorpoint = cgpointmake(0.5, 1);
btn.layer.position = cgpointmake(self.frame.size.width * 0.5, self.frame.size.height * 0.5);
btn.transform = cgaffinetransformmakerotation(angle * bi);
[btn addtarget:self action:@selector(clickbtn:) forcontrolevents:uicontroleventtouchupinside];
[self.wheelview addsubview:btn];
}
[self startrotating];
}
- (void)startrotating
{
if (self.timer) return;
self.timer = [cadisplaylink displaylinkwithtarget:self selector:@selector(updatetimer)];
[self.timer addtorunloop:[nsrunloop mainrunloop] formode:nsrunloopcommonmodes];
}
- (void)stoprotating
{
[self.timer invalidate];
self.timer = nil;
}
- (void)clickbtn:(uibutton *)btn
{
self.lastselectedbtn.selected = no;
btn.selected = yes;
self.lastselectedbtn = btn;
}
- (ibaction)clickcenterbtn:(id)sender {
self.userinteractionenabled = no;
[self stoprotating];
cabasicanimation *basicanimation = [cabasicanimation animationwithkeypath:@"transform.rotation"];
basicanimation.tovalue = @(m_pi * 2 * 5);
basicanimation.duration = 2;
basicanimation.timingfunction = [camediatimingfunction functionwithname:kcamediatimingfunctioneaseineaseout];
// basicanimation.removedoncompletion = no;
// basicanimation.fillmode = kcafillmodeforwards;
basicanimation.delegate = self;
[self.wheelview.layer addanimation:basicanimation forkey:nil];
}
- (void)animationdidstop:(caanimation *)anim finished:(bool)flag
{
self.userinteractionenabled = yes;
// 根据选中的按钮获取旋转的度数,
// 通过transform获取角度
cgfloat angle = atan2(self.lastselectedbtn.transform.b, self.lastselectedbtn.transform.a);
// 从实际上旋转转盘
self.wheelview.transform = cgaffinetransformmakerotation(-angle);
dispatch_after(dispatch_time(dispatch_time_now, (int64_t)(1 * nsec_per_sec)), dispatch_get_main_queue(), ^{
[self startrotating];
}); 
}
- (void)updatetimer
{
self.wheelview.transform = cgaffinetransformrotate(self.wheelview.transform, m_pi / 200);
}
- (void)dealloc
{
[self stoprotating];
}
@end

3、图片折叠

这个效果看起来很炫酷，但实际做起来是比较简单的。需要三个view，两个uiimageview，一个接受拖拽action的view。calayer里面有个contentrect属性，它可以设置layer里面的显示内容，利用这个属性，我们可以做在下载图片时，下载一点展示一点的效果。 在这里，我用这个属性来这是两张uiimageview各自展示一半的图片，然后将这两张imageview拼接在一起，显示完整的图片。

在一个覆盖这张完整图片的view上添加拖拽手势，以实现动画过程。

这里有一个新的图层需要学习下，cagradientlayer，它是用来做颜色渐变的，用法与calayer的用法相似：

属性代码：

cagradientlayer *gradientlayer = [cagradientlayer layer];
gradientlayer.frame = self.bottomview.bounds;
gradientlayer.opacity = 0;
gradientlayer.colors = @[(id)[uicolor clearcolor].cgcolor, (id)[uicolor blackcolor].cgcolor];
self.gradientlayer = gradientlayer;
[self.bottomview.layer addsublayer:gradientlayer];
// 设置渐变颜色
// gradientl.colors = @[(id)[uicolor redcolor].cgcolor,(id)[uicolor greencolor].cgcolor,(id)[uicolor yellowcolor].cgcolor];
// 设置渐变定位点
// gradientl.locations = @[@0.1,@0.4,@0.5];
// 设置渐变开始点，取值0~1
// gradientl.startpoint = cgpointmake(0, 1);

设置好之后，在pan手势的方法里面不断改变gradientlayer的opacity即可达到想要的效果。

catransform3d有个m34属性，可以设置透视度，一般将这个值设置为- 1 / 500.0，特定需求可以微调这个值。

代码：

#import "viewcontroller.h"
@interface viewcontroller ()
@property (weak, nonatomic) iboutlet uiimageview *topview;
@property (weak, nonatomic) iboutlet uiimageview *bottomview;
@property (weak, nonatomic) iboutlet uiview *containview;
@property (nonatomic, weak) cagradientlayer *gradientlayer;
@end
@implementation viewcontroller

- (void)viewdidload {
[super viewdidload];
// do any additional setup after loading the view, typically from a nib.
[self setupotherview];
//设置渐变的阴影
[self setupshadow];
}
- (void)setupotherview
{
//设置contentsrect用来表示图片显示的大小，可以做边下载边显示的ui效果,取值是(0--1)
self.topview.layer.contentsrect = cgrectmake(0, 0, 1, 0.5);
self.topview.layer.anchorpoint = cgpointmake(0.5, 1);
self.bottomview.layer.contentsrect = cgrectmake(0, 0.5, 1, 0.5);
self.bottomview.layer.anchorpoint = cgpointmake(0.5, 0);
uipangesturerecognizer *gesture = [[uipangesturerecognizer alloc] initwithtarget:self action:@selector(pan:)];
[self.containview addgesturerecognizer:gesture];
}
- (void)setupshadow
{
cagradientlayer *gradientlayer = [cagradientlayer layer];
gradientlayer.frame = self.bottomview.bounds;
gradientlayer.opacity = 0;
gradientlayer.colors = @[(id)[uicolor clearcolor].cgcolor, (id)[uicolor blackcolor].cgcolor];
self.gradientlayer = gradientlayer;
[self.bottomview.layer addsublayer:gradientlayer];
// 设置渐变颜色
// gradientl.colors = @[(id)[uicolor redcolor].cgcolor,(id)[uicolor greencolor].cgcolor,(id)[uicolor yellowcolor].cgcolor];
// 设置渐变定位点
// gradientl.locations = @[@0.1,@0.4,@0.5];
// 设置渐变开始点，取值0~1
// gradientl.startpoint = cgpointmake(0, 1);
}
- (void)pan:(uipangesturerecognizer *)recognizer
{
cgfloat y = [recognizer translationinview:self.containview].y;
if (y >= 300) y = 300;
if (y <= -300) y = -300;
// 旋转角度,往下逆时针旋转
cgfloat angle = -y / 320.0 * m_pi;
self.topview.layer.transform = catransform3didentity;
catransform3d transfrom = catransform3didentity;
transfrom.m34 = -1 / 500.0;
self.topview.layer.transform = catransform3drotate(transfrom, angle, 1, 0, 0);
self.gradientlayer.opacity = y / 300.0;
if (recognizer.state == uigesturerecognizerstateended) {

// 弹簧效果的动画
// springwithdamping:弹性系数,越小，弹簧效果越明显
[uiview animatewithduration:0.5 delay:0 usingspringwithdamping:0.3 initialspringvelocity:11 options:uiviewanimationoptioncurveeaseinout animations:^{
self.topview.layer.transform = catransform3didentity;
self.gradientlayer.opacity = 0;
} completion:nil];
}
}
@end

4、旋转进度条

圆圈旋转一般都是放在hud上吧。记得以前我也做过一个类似的功能，那时候还没现在这样的知识储备，只能是用cakeyframeanimation做，让美工做出了一根顶部是一个小白点，除此之外，很长的那部分是为clearcolor的小矩形，然后我设置它的anchorpoint，给 cakeyframeanimation添加一个圆形的path，然后围绕这个path旋转，做是勉强做出来，但是很不好看吧。

现在可以有更好的选择了，careplicatorlayer（复制图层）。我们可以在复制图层里面添加一个instance图层，如果设置了复制图层的instancecount，假如让instancecount == 5， 那么复制图层会自动帮我们复制5个跟instance图层一样的图层（事实上，我们可以在一开始就给instance图层设置动画，那么在复制的时候，一样会把动画也复制过来），除此之外，还可以设置复制图层里面的instance图层的transfrom，从而实现一定的布局。复制图层里面还有一个instancedelay，它表示延迟多少时间开始动画等等。

这个demo就是用了上面所说的实现的，代码：

#import "viewcontroller.h"
@interface viewcontroller ()
@property (weak, nonatomic) iboutlet uiview *containview;
@end
@implementation viewcontroller
- (void)viewdidload {
[super viewdidload];
// do any additional setup after loading the view, typically from a nib.

[self setupreplicatorlayerandanimation];
}
- (void)setupreplicatorlayerandanimation
{
careplicatorlayer *replicatorlayer = [careplicatorlayer layer];
replicatorlayer.frame = self.containview.layer.bounds;
[self.containview.layer addsublayer:replicatorlayer];
calayer *layer = [calayer layer];
layer.frame = cgrectmake(self.containview.frame.size.width * 0.5, 20, 16, 16);
layer.backgroundcolor = [uicolor redcolor].cgcolor;
layer.cornerradius = layer.frame.size.width / 2;
//这一句可以将初始过程移除掉
layer.transform = catransform3dmakescale(0, 0, 0);
[replicatorlayer addsublayer:layer];
replicatorlayer.instancecount = 22;
cabasicanimation *basican = [cabasicanimation animationwithkeypath:@"transform.scale"];
basican.fromvalue = @1;
basican.tovalue = @0;
basican.duration = 1;
basican.repeatcount = maxfloat;
[layer addanimation:basican forkey:nil];
replicatorlayer.instancedelay = basican.duration / (double)replicatorlayer.instancecount;
replicatorlayer.instancetransform = catransform3dmakerotation(2 * m_pi / replicatorlayer.instancecount, 0, 0, 1);
}
@end

5、粒子效果

这个东西就是careplicatorlayer（复制图层）和core graphics的结合吧，我是采用uibezierpath来绘制线条，然后将绘制好的path赋值给小球的animation路径，然后将小球添加到复制图层，设置下instancecount，设置下延迟时间，效果就出来了。

代码：

#import "zydrawview.h"
@interface zydrawview ()
@property (nonatomic, strong) uibezierpath *bezierpath;
@property (nonatomic, weak) careplicatorlayer *replicatorlayer;
@property (nonatomic, weak) calayer *norlayer;
@end
static int _count = 0;
@implementation zydrawview
- (uibezierpath *)bezierpath
{
if (_bezierpath == nil) {
_bezierpath = [[uibezierpath alloc] init];
}
return _bezierpath;
}
- (void)awakefromnib
{
careplicatorlayer *replicatorlayer = [careplicatorlayer layer];
replicatorlayer.frame = self.bounds;
[self.layer addsublayer:replicatorlayer];
calayer *layer = [calayer layer];
layer.frame = cgrectmake(0, -200, 10, 10);
layer.cornerradius = layer.frame.size.width * 0.5;
layer.backgroundcolor = [uicolor redcolor].cgcolor;
[replicatorlayer addsublayer:layer];
self.replicatorlayer = replicatorlayer;
self.norlayer = layer;
}
- (void)touchesbegan:(nsset<uitouch *> *)touches withevent:(uievent *)event
{
cgpoint curpoint = [[touches anyobject] locationinview:self];
[self.bezierpath movetopoint:curpoint];

}
- (void)touchesmoved:(nsset<uitouch *> *)touches withevent:(uievent *)event
{
_count++;
cgpoint curpoint = [[touches anyobject] locationinview:self];
[self.bezierpath addlinetopoint:curpoint];
[self setneedsdisplay];
}
- (void)startanimation
{
cakeyframeanimation *keyframean = [cakeyframeanimation animationwithkeypath:@"position"];
keyframean.path = self.bezierpath.cgpath;
keyframean.duration = 4;
keyframean.repeatcount = maxfloat;
[self.norlayer addanimation:keyframean forkey:nil];
self.replicatorlayer.instancecount = _count;
self.replicatorlayer.instancedelay = 0.1;
}
- (void)redraw
{
_bezierpath = nil;
_count = 1;
[self.norlayer removeallanimations];

[self setneedsdisplay];
}
- (void)drawrect:(cgrect)rect
{
[self.bezierpath stroke];
}
@end

以上内容是小编给大家介绍的core animation一些demo总结 （动态切换图片、大转盘、图片折叠、进度条等动画效果），希望对大家以上帮助！