纯代码实现图片预览

1UI效果图

2.代码实现

////  ViewController.m//  04-图片浏览器////  Created by liuhang on 15/11/20.//  Copyright © 2015年 liuhang. All rights reserved.//#import "ViewController.h"/* 1.查看界面元素需要哪些标签      UIImageView 图片显示      UIButton 按钮      UILabel  标签   @property  生成set和get 并生成员变量 _noLabel  2.代码布局    注意点 ：  UIImage 是图片，不是控件；他的父类为NSObject;              UIImageView是加载图片的控件，父类为UIView 3.设置监听，实现功能 */@interface ViewController ()// 定义属性名称// 1.序号标签@property (nonatomic ,strong)  UILabel *noLabel;// 2.图片按钮@property (nonatomic , strong) UIImageView *iconImage;// 3.文字描述标签@property (nonatomic , strong) UILabel *descLabel;// 4.左按钮@property (nonatomic , strong) UIButton *leftButton;// 5.右按钮@property (nonatomic , strong) UIButton *rightButton;@end@implementation ViewController// 初始化加载 : 在viveDidLoad创建界面- (void)viewDidLoad {        [super viewDidLoad];        // 1.添加序号标签  slef.noLabel    _noLabel =  [[UILabel alloc] initWithFrame:CGRectMake(0, 20, self.view.bounds.size.width, 40)];    _noLabel.text = @"1/5";  // 设置文本内容    _noLabel.textAlignment = NSTextAlignmentCenter;    NSLog(@"屏幕的宽度 = %f",self.view.bounds.size.width);  // 414(6s)    [self.view addSubview:_noLabel];  // 将视图添加到父视图        // 2.添加图片    CGFloat imageW = 200;    CGFloat imageH = 200;    // 图片居中，(获取屏幕长度 - 图片宽度) * 0.5   乘法的效率要不除法的效率高一点    CGFloat imageX = (self.view.bounds.size.width - imageW) * 0.5;    // 高度比序号标签高30    CGFloat imageY = _noLabel.bounds.size.height + 30;    _iconImage = [[UIImageView alloc] initWithFrame:CGRectMake(imageX, imageY, imageW, imageH)];    // _iconButton.backgroundColor  = [UIColor redColor];  设置背景颜色检测正确性    _iconImage.image = [UIImage imageNamed:@"biaoqingdi"];  // 设置背景图片    [self.view addSubview:_iconImage];        // 3.描述文字    // CGRectGetMaxY是获取当前控件y坐标值 + 控件高度的值    CGFloat descY = CGRectGetMaxY(self.iconImage.frame);    _descLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, descY , self.view.bounds.size.width, 100)];    _descLabel.text = @"表情帝";    _descLabel.textColor = [UIColor redColor];  // 设置文本颜色    _descLabel.textAlignment = NSTextAlignmentCenter;    [self.view addSubview:_descLabel];        // 4.添加左按钮    _leftButton = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 40)];  // 初始化按钮位置    // 动态设置按钮位置    CGFloat centerY = self.iconImage.center.y;    CGFloat centerX = self.iconImage.center.x * 0.3;    _leftButton.center = CGPointMake(centerX, centerY);    // 按钮设置背景图片只能通过set方法    [_leftButton setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal];    [_leftButton setBackgroundImage:[UIImage imageNamed:@"left_highlighted"] forState:UIControlStateHighlighted];    [self.view addSubview:_leftButton];        // 5.设置右按钮    _rightButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];    _rightButton.center = CGPointMake(self.view.bounds.size.width - centerX, centerY);    // 按钮设置背景图片只能通过set方法    [_rightButton setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal];    [_rightButton setBackgroundImage:[UIImage imageNamed:@"right_highlighted"] forState:UIControlStateHighlighted];    [self.view addSubview:_rightButton];}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end