iOS关于启动页自定义特殊处理

平常开发中对于启动页可能会有一些特别的要求，比如在启动页加动画或加一些按键可以响应事件等，最近项目中要在启动页增加版本号，因为版本号是不断的改变，所以要动态实现把它加到启动页上；在XCode上面配置的Launch Images Source或Launch Screen FIle(IOS8以上会优先调用这个作为启动项)都是保存一张静态图片；

原理：

其实原理也是很简单，启动页还是运用Launch Images Source的内容，然后在做一个视图在最上层，视图的背景用启动项的那张图，让人误以为还在启动中，启动页加载完成后，就显示这层视图，在2秒后再把这层视图删除，产生一个过度的假启动页效果；而我们自定义的动作就可以在这层视图上进行；下面将通过Coding.net的APP讲解这个功能；

一：创建一个视图EaseStartView

EaseStartView.h文件内容：

#import <UIKit/UIKit.h>

@interface EaseStartView : UIView
+ (instancetype)startView;

- (void)startAnimationWithCompletionBlock:(void(^)(EaseStartView *easeStartView))completionHandler;
@end

EaseStartView.m文件内容：

#import "EaseStartView.h"
#import <NYXImagesKit/NYXImagesKit.h>
#import "StartImagesManager.h"

@interface EaseStartView ()
@property (strong, nonatomic) UIImageView *bgImageView, *logoIconView;
@property (strong, nonatomic) UILabel *descriptionStrLabel;
@end

@implementation EaseStartView

+ (instancetype)startView{
UIImage *logoIcon = [UIImage imageNamed:@"logo_coding_top"];
StartImage *st = [[StartImagesManager shareManager] randomImage];
return [[self alloc] initWithBgImage:st.image logoIcon:logoIcon descriptionStr:st.descriptionStr];
}

- (instancetype)initWithBgImage:(UIImage *)bgImage logoIcon:(UIImage *)logoIcon descriptionStr:(NSString *)descriptionStr{
self = [super initWithFrame:kScreen_Bounds];
if (self) {
//add custom code
UIColor *blackColor = [UIColor blackColor];
self.backgroundColor = blackColor;

_bgImageView = [[UIImageView alloc] initWithFrame:kScreen_Bounds];
_bgImageView.contentMode = UIViewContentModeScaleAspectFill;
_bgImageView.alpha = 0.0;
[self addSubview:_bgImageView];

[self addGradientLayerWithColors:@[(id)[blackColor colorWithAlphaComponent:0.4].CGColor, (id)[blackColor colorWithAlphaComponent:0.0].CGColor] locations:nil startPoint:CGPointMake(0.5, 0.0) endPoint:CGPointMake(0.5, 0.4)];

_logoIconView = [[UIImageView alloc] init];
_logoIconView.contentMode = UIViewContentModeScaleAspectFit;
[self addSubview:_logoIconView];
_descriptionStrLabel = [[UILabel alloc] init];
_descriptionStrLabel.font = [UIFont systemFontOfSize:10];
_descriptionStrLabel.textColor = [UIColor colorWithWhite:1.0 alpha:0.5];
_descriptionStrLabel.textAlignment = NSTextAlignmentCenter;
_descriptionStrLabel.alpha = 0.0;
[self addSubview:_descriptionStrLabel];

[_descriptionStrLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.centerX.equalTo(@[self, _logoIconView]);
make.height.mas_equalTo(10);
make.bottom.equalTo(self.mas_bottom).offset(-15);
make.left.equalTo(self.mas_left).offset(20);
make.right.equalTo(self.mas_right).offset(-20);
}];

[_logoIconView mas_makeConstraints:^(MASConstraintMaker *make) {
make.centerX.equalTo(self);
make.top.mas_equalTo(kScreen_Height/7);
make.width.mas_equalTo(kScreen_Width *2/3);
make.height.mas_equalTo(kScreen_Width/4 *2/3);
}];

[self configWithBgImage:bgImage logoIcon:logoIcon descriptionStr:descriptionStr];
}
return self;
}

- (void)configWithBgImage:(UIImage *)bgImage logoIcon:(UIImage *)logoIcon descriptionStr:(NSString *)descriptionStr{
bgImage = [bgImage scaleToSize:[_bgImageView doubleSizeOfFrame] usingMode:NYXResizeModeAspectFill];
self.bgImageView.image = bgImage;
self.logoIconView.image = logoIcon;
self.descriptionStrLabel.text = descriptionStr;
[self updateConstraintsIfNeeded];
}

- (void)startAnimationWithCompletionBlock:(void(^)(EaseStartView *easeStartView))completionHandler{
[[UIApplication sharedApplication].keyWindow
addSubview:self];
[[UIApplication sharedApplication].keyWindow
bringSubviewToFront:self];
_bgImageView.alpha = 0.0;
_descriptionStrLabel.alpha = 0.0;

@weakify(self);
[UIView animateWithDuration:2.0 animations:^{
@strongify(self);
self.bgImageView.alpha = 1.0;
self.descriptionStrLabel.alpha = 1.0;
} completion:^(BOOL finished) {
[UIView animateWithDuration:0.6 delay:0.3 options:UIViewAnimationOptionCurveEaseIn animations:^{
@strongify(self);
[self setX:-kScreen_Width];
} completion:^(BOOL finished) {
@strongify(self);
[self removeFromSuperview];
if (completionHandler) {
completionHandler(self);
}
}];
}];
}

@end

其实本实例中最为关键的内容在方法startAnimationWithCompletionBlock里

[[UIApplication sharedApplication].keyWindow addSubview:self];
[[UIApplication sharedApplication].keyWindow bringSubviewToFront:self];

代码就是把这个视图设置成在最前的最上层，这样就可以盖住程序中的页面；

_bgImageView.alpha = 0.0;
_descriptionStrLabel.alpha = 0.0;

这个是为了下面的动画做准备，若是直接用背景图可以把这两个都设置成0.99这样就不会有一闪的错觉；

@weakify(self);
[UIView animateWithDuration:2.0 animations:^{
@strongify(self);
self.bgImageView.alpha = 1.0;
self.descriptionStrLabel.alpha = 1.0;
} completion:^(BOOL finished) {
[UIView animateWithDuration:0.6 delay:0.3 options:UIViewAnimationOptionCurveEaseIn animations:^{
@strongify(self);
[self setX:-kScreen_Width];
} completion:^(BOOL finished) {
@strongify(self);
[self removeFromSuperview];
if (completionHandler) {
completionHandler(self);
}
}];
}];

这边是动画效果，时间设置为2秒，因为这边第一个动画完还有一个左移出启动页的效果；当动画结束后就可以 [self removeFromSuperview];

二：调用启动页视图

在AppDelegate中的didFinishLaunchingWithOptions进行调用；

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.window.backgroundColor = [UIColor whiteColor];

//网络
[[AFNetworkActivityIndicatorManager sharedManager] setEnabled:YES];
[[AFNetworkReachabilityManager sharedManager] startMonitoring];

//设置导航条样式
[self customizeInterface];
[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationFade];

if ([Login isLogin]) {
[self setupTabViewController];
}else{
[UIApplication sharedApplication].applicationIconBadgeNumber = 0;
[self setupIntroductionViewController];
}
[self.window makeKeyAndVisible];
[FunctionIntroManager showIntroPage];

EaseStartView *startView = [EaseStartView startView];
@weakify(self);
[startView startAnimationWithCompletionBlock:^(EaseStartView *easeStartView) {
@strongify(self);
//可以做其它事情
}];

return YES;
}

注意，EaseStartView代码的位置是要放在最后面，因为要让它盖在最上层，就要后面加载，这样就可以盖在登录页面上面或者主页上；到这就已经可以成功启动页的效果；

三：下面实例为项目中用到的动态加载版本号到启动页上

#import "StartUpView.h"

@interface StartUpView()
@property (strong, nonatomic) UIImageView *bgImageView;
@property (strong, nonatomic) UILabel *descriptionStrLabel;
@end

@implementation StartUpView

+ (instancetype)startView
{
UIImage *bgImage=kshamLaunchImage;
return [[self alloc] initWithBgImage:bgImage];
}

- (instancetype)initWithBgImage:(UIImage *)bgImage
{
self = [super initWithFrame:Main_Screen_Bounds];
if (self) {

_bgImageView = [[UIImageView alloc] initWithFrame:Main_Screen_Bounds];
_bgImageView.contentMode = UIViewContentModeScaleAspectFill;
_bgImageView.alpha = 0;
_bgImageView.image=bgImage;
[self addSubview:_bgImageView];

_descriptionStrLabel = [[UILabel alloc] init];
_descriptionStrLabel.font = [UIFont systemFontOfSize:15];
_descriptionStrLabel.textColor = [UIColor blackColor];
_descriptionStrLabel.textAlignment = NSTextAlignmentCenter;
_descriptionStrLabel.alpha = 0;
_descriptionStrLabel.text=[NSString stringWithFormat:@"版本号为:%@",appVersion];
[self addSubview:_descriptionStrLabel];

[_descriptionStrLabel mas_makeConstraints:^(MASConstraintMaker *make) {
make.height.mas_equalTo(50);
make.bottom.equalTo(self.mas_bottom).offset(-15);
make.left.equalTo(self.mas_left).offset(20);
make.right.equalTo(self.mas_right).offset(-20);
}];
}
return self;
}

- (void)startAnimationWithCompletionBlock:(void(^)(StartUpView *easeStartView))completionHandler{
[[UIApplication sharedApplication].keyWindow addSubview:self];
[[UIApplication sharedApplication].keyWindow bringSubviewToFront:self];
_bgImageView.alpha = 0.99;
_descriptionStrLabel.alpha = 0.99;

@weakify(self);
[UIView animateWithDuration:2.0 animations:^{
@strongify(self);
self.bgImageView.alpha = 1.0;
self.descriptionStrLabel.alpha = 1.0;
} completion:^(BOOL finished) {
[self removeFromSuperview];
if (completionHandler) {
completionHandler(self);
}
}];
}
@end