ios开发之父子视图的关系

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];

    self.window.backgroundColor = [UIColor whiteColor];

    self.window.rootViewController = [[UIViewController alloc] init];

    self.window.rootViewController.view.userInteractionEnabled = NO;

    

    //========================================

    //若是多个视图添加到同一个父视图上，公共部分，后添加的会覆盖先添加的

    

    //建立红色视图

    UIView * redView = [[UIView alloc] initWithFrame:CGRectMake(50, 50, 100, 100)];

    redView.backgroundColor = [UIColor redColor];

    redView.tag = 10;

    [self.window addSubview:redView];

    

    //建立黄色视图

    UIView * yellowView = [[UIView alloc] initWithFrame:CGRectMake(80, 80, 100, 100)];

    yellowView.backgroundColor = [UIColor yellowColor];

    yellowView.tag = 20;

    [self.window addSubview:yellowView];

    

    //建立绿色视图

    UIView * greenView = [[UIView alloc] initWithFrame:CGRectMake(110, 110, 100, 100)];

    greenView.backgroundColor = [UIColor greenColor];

    greenView.tag = 30;

    [self.window addSubview:greenView];

    

    

    //1.将一个视图的层次设置成最上面

    //- (void)bringSubviewToFront:(UIView *)view;

//    [_window bringSubviewToFront:redView];

    

    //2.将某个视图放到最下面

    //- (void)sendSubviewToBack:(UIView *)view;

//    [_window sendSubviewToBack:yellowView];

    

    //3.插入视图(若是被插入的视图已经显示在界面上，那么经过插入方法只是改变它的层次关系；若是被插入的视图没有添加到界面上，经过插入方法能够将视图添加到界面上，而且改变层次关系)

    //将某个视图插入到指定的视图上面

    //- (void)insertSubview:(UIView *)view aboveSubview:(UIView *)siblingSubview;

//    [_window insertSubview:greenView aboveSubview:redView];

    

    //将某个视图插入到指定视图的下面

    [_window insertSubview:greenView belowSubview:yellowView];

    

    

    

    

    

    

    

    [self.window makeKeyAndVisible];

    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