#import <UIKit/UIKit.h>

@class BIDViewController;    // 声明引用的文件

@interface BIDAppDelegate : UIResponder <UIApplicationDelegate>   // 实现UIApplicationDelegate协议中的方法，用于处理UIApplication接收的事件     

@property (strong, nonatomic) UIWindow *window;    // UIView的子类, 是所有UIView的根，管理和协调的应用程序的显示

@property (strong, nonatomic) BIDViewController *viewController;

@end

#import "BIDAppDelegate.h"

#import "BIDViewController.h"

@implementation BIDAppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    // 初始化UIWindow
    // Override point for customization after application launch.
    self.viewController = [[BIDViewController alloc] initWithNibName:@"BIDViewController" bundle:nil];    // 初始化BIDViewController并且指定controller的xib文件, xib文件就是布局文件
    self.window.rootViewController = self.viewController;    // 指定window的根视图控制器
    [self.window makeKeyAndVisible];    // 让window显示在屏幕上
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

@end