一次立竿见影的启动时间优化

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions;复制代码

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    NSLog(@"didFinishLaunchingWithOptions 开始执行");

    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    BLTabBarController *tabBarVc = [BLTabBarController new];
    self.window.rootViewController = tabBarVc;
    [self.window makeKeyAndVisible];

    NSLog(@"didFinishLaunchingWithOptions 跑完了");

    return YES;
}复制代码

2017-08-15 10:46:57.860 Demo[1404:325698] didFinishLaunchingWithOptions 开始执行
2017-08-15 10:46:57.862 Demo[1404:325698] 开始加载 BLTabBarController 的 viewDidLoad
2017-08-15 10:46:57.874 Demo[1404:325698] didFinishLaunchingWithOptions 跑完了
2017-08-15 10:46:57.876 Demo[1404:325698] 开始加载 BLViewController 的 viewDidLoad, 然后执行一堆初始化的操作复制代码

2017-08-15 11:09:03.661 Demo[1458:349413] didFinishLaunchingWithOptions 开始执行
2017-08-15 11:09:03.663 Demo[1458:349413] 开始加载 BLTabBarController 的 viewDidLoad
2017-08-15 11:09:03.664 Demo[1458:349413] 开始加载 BLViewController 的 viewDidLoad, 然后执行一堆初始化的操作
2017-08-15 11:09:03.676 Demo[1458:349413] didFinishLaunchingWithOptions 跑完了复制代码

/**
 * 注意: 这个类负责所有的 didFinishLaunchingWithOptions 延迟事件的加载.
 * 以后引入第三方需要在 didFinishLaunchingWithOptions 里初始化或者我们自己的类需要在 didFinishLaunchingWithOptions 初始化的时候,
 * 要考虑尽量少的启动时间带来好的用户体验, 所以应该根据需要减少 didFinishLaunchingWithOptions 里耗时的操作.
 * 第一类: 比如日志 / 统计等需要第一时间启动的, 仍然放在 didFinishLaunchingWithOptions 中.
 * 第二类: 比如用户数据需要在广告显示完成以后使用, 所以需要伴随广告页启动, 只需要将启动代码放到 startupEventsOnADTimeWithAppDelegate 方法里.
 * 第三类: 比如直播和分享等业务, 肯定是用户能看到真正的主界面以后才需要启动, 所以推迟到主界面加载完成以后启动, 只需要将代码放到 startupEventsOnDidAppearAppContent 方法里.
 */

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface BLDelayStartupTool : NSObject

/**
 * 启动伴随 didFinishLaunchingWithOptions 启动的事件.
 * 启动类型为:日志 / 统计等需要第一时间启动的.
 */
+ (void)startupEventsOnAppDidFinishLaunchingWithOptions;

/**
 * 启动可以在展示广告的时候初始化的事件.
 * 启动类型为: 用户数据需要在广告显示完成以后使用, 所以需要伴随广告页启动.
 */
+ (void)startupEventsOnADTime;

/**
 * 启动在第一个界面显示完(用户已经进入主界面)以后可以加载的事件.
 * 启动类型为: 比如直播和分享等业务, 肯定是用户能看到真正的主界面以后才需要启动, 所以推迟到主界面加载完成以后启动.
 */
+ (void)startupEventsOnDidAppearAppContent;

@end

NS_ASSUME_NONNULL_END复制代码

#import "BLDelayStartupTool.h"

static BOOL _isCalledStartupEventsOnAppDidFinishLaunchingWithOptions = NO;
static BOOL _isCalledStartupEventsOnADTimeWithAppDelegate = NO;
static BOOL _isCalledStartupEventsOnDidAppearAppContent = NO;
const NSTimeInterval kBLDelayStartupEventsToolCheckCallTimeInterval = 30;
@implementation BLDelayStartupTool

+ (void)load {
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(kBLDelayStartupEventsToolCheckCallTimeInterval * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [self checkStartupEventsDidLaunched];
    });
}

+ (void)checkStartupEventsDidLaunched {
    NSString *alertString = @"";
    if (!_isCalledStartupEventsOnAppDidFinishLaunchingWithOptions) {
        alertString = [alertString stringByAppendingString:@"AppDidFinishLaunching, "];
        [self startupEventsOnAppDidFinishLaunchingWithOptions];
    }
    if (!_isCalledStartupEventsOnADTimeWithAppDelegate) {
        alertString = [alertString stringByAppendingString:@"ADTime, "];
        [self startupEventsOnADTime];
    }
    if (!_isCalledStartupEventsOnDidAppearAppContent) {
        alertString = [alertString stringByAppendingString:@"DidAppearAppContent"];
        [self startupEventsOnDidAppearAppContent];
    }

    if (alertString.length > 0) {

#if DEBUG
        alertString = [alertString stringByAppendingString:@" 等延迟启动项没有启动, 这会造成应用奔溃"];
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"注意" message:alertString delegate:nil cancelButtonTitle:@"好的" otherButtonTitles:nil];
        [alertView show];
#endif
    }
}

+ (void)startupEventsOnAppDidFinishLaunchingWithOptions {
    _isCalledStartupEventsOnAppDidFinishLaunchingWithOptions = YES;
}

+ (void)startupEventsOnADTime {
    _isCalledStartupEventsOnADTimeWithAppDelegate = YES;
}

+ (void)startupEventsOnDidAppearAppContent {
    _isCalledStartupEventsOnDidAppearAppContent = YES;
}

@end复制代码

Total pre-main time: 2.2 seconds (100.0%)
 dylib loading time: 1.0 seconds (45.2%)
rebase/binding time: 100.05 milliseconds (4.3%)
    ObjC setup time: 207.21 milliseconds (9.0%)
   initializer time: 946.39 milliseconds (41.3%)
slowest intializers :
           libSystem.B.dylib :   8.54 milliseconds (0.3%)
 libBacktraceRecording.dylib :  46.30 milliseconds (2.0%)
        libglInterpose.dylib : 187.42 milliseconds (8.1%)
                     beiliao : 896.56 milliseconds (39.1%)复制代码