本节学习内容：
1.自动子视图布局的概念
2.自动布局视图的创建
3.自动布局子视图的实现
【ViewController.h】
#import<UIKit/UIKit.h>
@interface Viewcoontroller:UIViewController{
//创建父亲视图对象
UIView*_superView;
//左上角label
UILable* _label01;
//右上角
UILable* _label02;
//右下角
UILable* _label03;
//左下角
UILable* _label04;
UIView* _viewCenter;
}
@end
【ViewController.m】
#import"ViewController.h"
@interface ViewController()
@end
@implementation ViewConroller
-(void)viewdidLoad{
[super viewDidLoad];
//创建父视图
_superView=[[UIView alloc] init];
_superView.frame=CGRectMake[20,20,180,280);
_superView.backgroundColor=[UIColor blueColor];
//创建lable
_label01=[[UILabel alloc]init];
//位置相对于父亲视图
_label01.frame=CGRectMake(0,0,40,40);
_label01=[[UILabel alloc]init];
_label01.text=@"1";
_label01.backgroundColor=[UIColor greenColor];
_label02=[[UILabel alloc]init];
_label02.frame=CGRectMake(180-40,40,40,40);
_label02.text=@"2";
_label02.backgroundColor=[UIColor greenColor];
_label03=[[UILabel alloc]init];
_label03.frame=CGRectMake(180-40,280-40,40,40);
_label03.text=@"3";
_label03.backgroundColor=[UIColor greenColor];
_label04=[[UILabel alloc]init];
_label04.frame=CGRectMake(0,280-40,40,40);
_label04.text=@"4";
_label04.backgroundColor=[UIColor greenColor];
_superView addSubview:_label01];
_superView addSubview:_label02];
_superView addSubview:_label03];
_superView addSubview:_label04];
[self.view addSubview:_superView];
_viewCenter=[[UIView allc]init];
_viewCenter.frame=CGRectMake(0,0,_superView.bounds.size.widith,40);
_viewCenter.center=CGPointMake(180/2,280/2);
_viewCenter.backgroundColor={UIColor orangeColor];
[_superView addSubview:_viewCenter];
//自动布局属性设置，通地此变理来调整视图在父视图中的位置和大小FlexibleHeight;指高度，Flexiblewidth：指宽度
//距离上，下，宽度都是可变的
_viewCenter.autoresizingMask=UIViewAutoresizingFlexibleWidth UIViewAutoresizingFlexibleTopMargin UIViewAutoresizingFlexibleBottomMargin;
//视图距离父亲视图的左侧可变化
_label02.autoresizingMask=UIViewAutoresizingFlexibleLeftMargin;
//上边缘与左边缘随父视图变化
_label03.autoresizingMask=UIViewAutoresizingFlexibleTopMargin UIViewAutoresizingFlexibleLeftMargin;
//上边缘随父视图变化
_label04.autoresizingMask=UIViewAutoresizingFlexibleTopMargin;
}
//自动缩放
-(void)touchesBegan:(NSSet<UITouch*>*)touches withEvent:(UIEvent *)event{
static BOOL isLarge=NO;
[UIView beginAnimations:nil context:nill];
[UIView setAnimationDuration:1];
if(isLarge==NO){
_superView.frame=CGRectMake(10,10,300,480);
}else｛
_superView.frame=CGRectMake(20,20,180,280);
｝
[UIView commitAnimatios];
isLarge=!isLarge
}
