视图

把某个视图插入到指定位置，跟数组一样，位置都是从0开始算。若插的位置最顶层视图位置，那么这个视图就插在最顶层。

//
//  ViewController.m
//  添加-视图
//
//  Created by cqy on 16/2/12.
//  Copyright © 2016年 程清杨. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
   
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 200, 100)];
    view.backgroundColor = [UIColor yellowColor];
    [self.view addSubview:view];
   
    UIView *view1 = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 200, 100)];
    view1.backgroundColor = [UIColor redColor];
    [self.view addSubview:view1];
   
   
    UIView *view2 = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 200, 100)];
    view2.backgroundColor = [UIColor greenColor];
    [self.view addSubview:view2];
   
    UIView *view3 = [[UIView alloc] initWithFrame:CGRectMake(20, 70, 200, 100)];
    view3.backgroundColor = [UIColor colorWithRed:200/255.0 green:30/255.0 blue:5/255.0 alpha:1];
    [self.view addSubview:view3];
    //把某个视图插入到最顶层
    // [self.view insertSubview:<#(nonnull UIView *)#> aboveSubview:<#(nonnull UIView *)#>];
    //把某个视图插入到最底层
    //[self.view insertSubview:<#(nonnull UIView *)#> belowSubview:<#(nonnull UIView *)#>];
    //插入到指定位置，这个位置是从0开始
    //[self.view insertSubview:<#(nonnull UIView *)#> atIndex:<#(NSInteger)#>];
    [self.view insertSubview:view atIndex:0];
    [self.view insertSubview:view1 atIndex:1];
    [self.view insertSubview:view2 atIndex:2];
    //视图层次管理
    //把指定的视图拿到最顶层
    [self.view bringSubviewToFront:view];
    //把指定视图拿到最底层
    [self.view sendSubviewToBack:view];
    //把某个视图与另一个视图交换位置
    [self.view exchangeSubviewAtIndex:0 withSubviewAtIndex:1];
    //把个视图移除
    [view1 removeFromSuperview];
    //视图属性
    //视图隐藏：hidden，为BOOL值
    view.hidden = YES;
    //控制视图透明度：alpha，是一个CGFloat类型的变量，值在0~1之间
    view3.alpha = 0.5;
    // superview
    // 获取⽗视图
    UIView *superView = view.superview;
    NSLog(@"--%@",[superView class]);
    // subview
    // 获取⼦视图
    NSArray *subViews = self.view.subviews;
    NSLog(@"==%@",subViews);
    //tag通常
    view.tag = 100;
       // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end