UI2_IOS坐标系

//
//  AppDelegate.m
//  UI2_IOS坐标系
//
//  Created by zhangxueming on 15/6/29.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import "AppDelegate.h"

@interface AppDelegate ()

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.

//window的默认颜色是透明色
self.window.backgroundColor = [UIColor whiteColor];
//NSLog(@"window = %@", self.window);
NSLog(@"x = %.2f y=%.2f w = %.2f h = %.2f",self.window.frame.origin.x, self.window.frame.origin.y, self.window.frame.size.width, self.window.frame.size.height);
//ios坐标系
//frame坐标: 相对于父视图的坐标
//bounds坐标:ios坐标(起始点从(0,0)开始)

//状态栏的高度是20

CGRect frame = [[UIScreen mainScreen] bounds];
NSLog(@"x = %.2f y = %.2f w= %.2f h = %.2f", frame.origin.x, frame.origin.y, frame.size.width, frame.size.height);

UIWindow *window1 = [[UIWindow alloc] initWithFrame:CGRectMake(10, 50, self.window.frame.size.width-20, self.window.frame.size.height-100)];
window1.backgroundColor = [UIColor cyanColor];

[self.window addSubview:window1];

//使window1在最上层显示
[window1 makeKeyAndVisible];

//通常一个应用程序有一个Window(窗口)
//相当于一个容器
UIView *view1 = [[UIView alloc] initWithFrame:CGRectMake(20, 100, self.window.frame.size.width-40, 50)];
view1.backgroundColor = [UIColor redColor];

[self.window addSubview:view1];

//view1的retainCount加1
//NSLog(@"retainCount = %li", view1.retainCount);

self.window.rootViewController = nil;
return YES;
}