04-图片排列切换

ViewController.h文件中：

@interface ViewController : UIViewController

@property (weak, nonatomic) IBOutlet UISegmentedControl *segmentCtrl;

- (IBAction)indexChange:(UISegmentedControl *)sender;

@end

ViewController.m文件中：

#import "ViewController.h"

#define kImgWH 40
#define kExistCtrl 2 // 新增ImageView控件之前已存在的控件数目

@interface ViewController ()
{
    int _imgCount;  // 图片控件的个数
    UIButton *_btn;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    //初始化图片控件个数
    _imgCount = 9;
    
    // 先新增按钮控件（新增顺序不可调换）
    _btn = [[UIButton alloc] init];
    [_btn setTitle:@"新增" forState:UIControlStateNormal];
    [_btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [self.view addSubview:_btn];
    // 监听事件
    [_btn addTarget:self action:@selector(addImg) forControlEvents:UIControlEventTouchUpInside];
    
    // 再新增图片控件
    [self adjustImagePosWithColumns:2];
}

#pragma mark 调整图片位置的封装函数
- (void)adjustImagePosWithColumns:(int)columns
{
    CGFloat marginW = (self.view.frame.size.width - columns * kImgWH)/(columns + 1);
    CGFloat marginH = 20;
    CGFloat oneY = 80;
    
    // 调整图片或新增图片控件
    for (int i = 0; i < _imgCount; ++i) {
        int col = i % columns;
        int row = i / columns;
        
        int x = marginW + col * (marginW + kImgWH);
        int y = oneY + row * (marginH + kImgWH);
        
        CGRect frm = CGRectMake(x, y, kImgWH, kImgWH);
        
        if (self.view.subviews.count < _imgCount + kExistCtrl) {
            //动态创建UIImageView控件
            int no = i % 9;
            NSString *name = [NSString stringWithFormat:@"01%d.png", no];
            
            UIImageView *img = [[UIImageView alloc] init];
            img.image = [UIImage imageNamed:name];
            img.frame = frm;
            
            [self.view addSubview:img];
        }
        else {
            // 调整图片的位置
            UIView *child = self.view.subviews[i + kExistCtrl];
            child.frame = frm;
        }
    }
    
    // 调整按钮的位置
    int col = _imgCount % columns;
    int row = _imgCount / columns;
    int x = marginW + col * (marginW + kImgWH);
    int y = oneY + row * (marginH + kImgWH);
    
    CGRect frm = CGRectMake(x, y, kImgWH, kImgWH);
    _btn.frame = frm;
    
//    NSLog(@"子控件个数＝%lu", (unsigned long)self.view.subviews.count);
}

#pragma mark Segmented控件的值变化的监听事件
- (IBAction)indexChange:(UISegmentedControl *)sender {
    
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    
    int columns = (int)(sender.selectedSegmentIndex + 2);
    [self adjustImagePosWithColumns:columns];
    
    [UIView commitAnimations];
}

#pragma mark “新增”按钮的响应事件
- (void)addImg
{
    // 新增图片控件
    int no = _imgCount % 9;
    NSString *name = [NSString stringWithFormat:@"01%d.png", no];
    
    UIImageView *img = [[UIImageView alloc] init];
    img.image = [UIImage imageNamed:name];
    img.frame = CGRectMake(_btn.frame.origin.x, _btn.frame.origin.y, 0, 0);
//    img.frame = CGRectMake(0, 0, kImgWH, kImgWH);
    [self.view addSubview:img];

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    
    _imgCount += 1;
    int columns = (int)(self.segmentCtrl.selectedSegmentIndex + 2);
    [self adjustImagePosWithColumns:columns];
    
    [UIView commitAnimations];
}

 
@end

界面效果：