insertSubview浅析

• 最开始布局图:

• 测试1

• ViewController

// ViewController.h
#import <UIKit/UIKit.h>

@interface ViewController : UIViewController


@end


// ViewController.m
#import "ViewController.h"

@interface ViewController ()

/** 红色的view*/
@property (weak, nonatomic) IBOutlet UIView *redView;
/** 蓝色的view*/
@property (weak, nonatomic) IBOutlet UIView *blueView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    // 给self.view插入一个orangeView,并且这个orangeView是在self.blueView上的
    [self.view insertSubview:orangeView aboveSubview:self.blueView];

}

@end

• 效果图:

  
  
  

• 测试2

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    // 给self.view插入一个orangeView,并且这个orangeView是在self.redView上的
    // 默认在self.blueView的下面
    [self.view insertSubview:orangeView aboveSubview:self.redView];
}

• 效果图:

  
  
  

• 测试3

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    // 给self.view插入一个orangeView,并且这个orangeView是在self.blueView的下面
    // 默认在self.redView上面
    [self.view insertSubview:orangeView belowSubview:self.blueView];
}

• 效果图:

  
  

• 测试4

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    // 给self.view插入一个orangeView,并且这个orangeView是在self.redView的下面
    [self.view insertSubview:orangeView belowSubview:self.redView];
}

• 效果图:

  
  
  

• 测试5

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    [self.view insertSubview:orangeView atIndex:0];
}

• 效果图:

  
  
  

• 测试6

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    [self.view addSubview:orangeView];
    [orangeView bringSubviewToFront:self.blueView];
}

• 效果图:

  
  

• 测试7

- (void)viewDidLoad {
    [super viewDidLoad];

    // 1.创建一个橙色view
    UIView *orangeView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 50, 50)];
    // 2.设置背景色
    orangeView.backgroundColor = [UIColor orangeColor];
    // 3.设置位置
    orangeView.center = CGPointMake(175, 280);
    [self.view addSubview:orangeView];
    // self.view有3个子控件self.redView,self.blueView,orangeView
    // 添加的顺序为self.redView下标为0,self.blueView下标为1,orangeView下标为2
    // 如果没有下面这行代码,那么self.redView必定是显示在最底部,然后是self.blueView,最后是orangeView
    // 但是显示结果是self.blueView显示在最底部.就是因为下面这句代码
    // 笔者认为:它们三个都是self.view的子控件,sendSubviewToBack:self.blueView
    // 是把它们的顺序排布调换了一下，即排布之后的self.blueView下标为0,self.redView下标为1,orangeView下标为2，所以，绿色的view显示在最底部了.
    // 类似于[self.view insertSubview:self.blueView atIndex:0];方法
    [self.view sendSubviewToBack:self.blueView];
}

• 效果图: