一个布局的例子，类似 QQ 表情面板

QQFacePanel.m

//
//  ViewController.m
//  FaceDemo
//
//  Created by syxc on 15/10/31.
//  Copyright © 2015年 syxc. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
  [super viewDidLoad];
  
  UILabel *lblTitle = [[UILabel alloc] initWithFrame:CGRectMake(0, 20, self.view.frame.size.width, 40)];
  lblTitle.text = @"QQ表情面板";
  lblTitle.textAlignment = NSTextAlignmentCenter;
  lblTitle.font = [UIFont systemFontOfSize:20];
  [self.view addSubview:lblTitle];
  
  UIView *faceView = [[UIView alloc] initWithFrame:CGRectMake(0, CGRectGetMaxY(lblTitle.frame),
                                                              self.view.frame.size.width,
                                                              self.view.frame.size.height - lblTitle.frame.size.height + 20)];
  faceView.backgroundColor = [UIColor blackColor];
  [self.view addSubview:faceView];
  
  int faceCount = 105;  // 表情总数
  int count = 0;        // 列
  int row = 0;          // 行
  float spacing = 8.0;  // 间距
  int maxPerRow = floor(faceView.frame.size.width / (24 + spacing)); // 容器允许多少列合适
  
  for (int i = 0; i < faceCount; i++) {
    UIImageView *icon = [[UIImageView alloc] init];
    icon.image = [UIImage imageNamed:[NSString stringWithFormat:@"%d", i]];
    
    CGRect rect = CGRectMake(count * (spacing + 24), row * (spacing + 24), 24, 24);
    icon.frame = rect;
    
    if(count % maxPerRow == maxPerRow - 1) {
      count = 0;
      row++;
    } else {
      count++;
    }
    
    [faceView addSubview:icon];
    
    NSLog(@"face index:%d", i);
  }
}

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

@end