Image browser(demo15.03.14)

这是一个图片浏览的程序，是传智公开课的一个demo

代码如下

//
//  ViewController.m
//  ImageBroswer
//
//  Created by xin on 15-3-12.
//  Copyright (c) 2015年 Jackey. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
//序号标签
@property (nonatomic,strong) UILabel *noLabel;
//图片
@property (nonatomic,strong) UIImageView *icon;
//图片描述
@property (nonatomic,strong) UILabel *descriptionLabel;
//左边按钮
@property (nonatomic,strong) UIButton *leftButton;
//右边按钮
@property (nonatomic,strong) UIButton *rightButton;

//image index
@property (nonatomic,assign) int index;//不带星号 assign

@property (nonatomic,strong) NSArray *array;
//@property
// 1 setter getter
// 2 带下划线的成员变量
@end

@implementation ViewController

//array getter
-(NSArray *)array{
    //只有第一次调用getter的时候才会执行
    //其他时候直接返回
    if(_array==nil){
        NSDictionary *dic1 = @{@"name":@"biaoqingdi",@"desc":@"表情"};
        NSDictionary *dic2 = @{@"name":@"bingli",@"desc":@"病例"};
        NSDictionary *dic3 = @{@"name":@"chiniupa",@"desc":@"吃牛扒"};
        NSDictionary *dic4 = @{@"name":@"danteng",@"desc":@"蛋疼"};
        NSDictionary *dic5 = @{@"name":@"wangba",@"desc":@"王八"};
        
        _array = @[dic1,dic2,dic3,dic4,dic5];
    }
    return _array;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    //标签描述
    UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(0, 20, 320, 40)];
    //label.text = @"1/5";
    label.textAlignment = NSTextAlignmentCenter;
    [self.view addSubview:label];
    self.noLabel = label;
    
    //图片
    UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(60, 70, 200, 200)];
    //imageView.image = [UIImage imageNamed:@"biaoqingdi"];
    [self.view addSubview:imageView];
    self.icon = imageView;
    
    //图片描述
    UILabel *iconLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 300, 320, 80)];
    //iconLabel.text = @"什么表情都弱爆了";
    iconLabel.textAlignment = NSTextAlignmentCenter;
    [self.view addSubview:iconLabel];
    self.descriptionLabel = iconLabel;
    
    //left icon
    UIButton *leftBtn = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 40)];
    leftBtn.center = CGPointMake(self.icon.frame.origin.x/2, self.icon.center.y);
    [leftBtn setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal];
    [self.view addSubview:leftBtn];
    [leftBtn addTarget:self action:@selector(leftClick) forControlEvents:UIControlEventTouchUpInside];
    self.leftButton = leftBtn;
    
    
    //right btn
    UIButton *rightBtn = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 40)];
    rightBtn.center = CGPointMake(self.view.frame.size.width- self.icon.frame.origin.x/2, self.icon.center.y);
    [rightBtn setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal];
    [self.view addSubview:rightBtn];
    [rightBtn addTarget:self action:@selector(rightClick) forControlEvents:UIControlEventTouchUpInside];
    self.rightButton = rightBtn;
    
    [self changeImage];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
/** 改变图像数据 */
-(void)changeImage{
    
    self.noLabel.text = [NSString stringWithFormat:@"%d/%d",self.index+1,5];
    self.icon.image = [UIImage imageNamed:self.array[self.index][@"name"]];
    self.descriptionLabel.text = self.array[self.index][@"desc"];
    
    self.rightButton.enabled = (self.index !=4);
    self.leftButton.enabled = (self.index!=0);
    
}
/** 左边按钮 */
-(void)leftClick{
    NSLog(@"left");
    self.index--;
    [self changeImage];
}
-(void)rightClick{
    NSLog(@"right");
    self.index++;
    [self changeImage];
}

@end

优化代码，使用懒加载

//
//  ViewController.m
//  ImageBroswer
//
//  Created by xin on 15-3-12.
//  Copyright (c) 2015年 Jackey. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
//序号标签
@property (nonatomic,strong) UILabel *noLabel;
//图片
@property (nonatomic,strong) UIImageView *icon;
//图片描述
@property (nonatomic,strong) UILabel *descriptionLabel;
//左边按钮
@property (nonatomic,strong) UIButton *leftButton;
//右边按钮
@property (nonatomic,strong) UIButton *rightButton;

//image index
@property (nonatomic,assign) int index;//不带星号 assign

@property (nonatomic,strong) NSArray *array;
//@property
// 1 setter getter
// 2 带下划线的成员变量
@end

@implementation ViewController

//array getter
-(NSArray *)array{
    //只有第一次调用getter的时候才会执行
    //其他时候直接返回
    if(_array==nil){
        NSString *path = [[NSBundle mainBundle] pathForResource:@"ImageData" ofType:@"plist"];
        _array= [NSArray arrayWithContentsOfFile:path];
    }
    return _array;
}

-(UILabel *)noLabel{
    if(_noLabel==nil){
        _noLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 20, 320, 40)];
        _noLabel.textAlignment = NSTextAlignmentCenter;
        [self.view addSubview:_noLabel];
    }
    return _noLabel;
}

-(UIImageView *)icon{
    if(_icon==nil){
        _icon = [[UIImageView alloc]initWithFrame:CGRectMake(60, 70, 200, 200)];
        [self.view addSubview:_icon];
    }
    return _icon;
}

-(UILabel *)descriptionLabel{
    if(_descriptionLabel==nil){
        _descriptionLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 300, 320, 80)];
        _descriptionLabel.numberOfLines = 0;
        _descriptionLabel.textAlignment = NSTextAlignmentCenter;
        [self.view addSubview:_descriptionLabel];
    }
    return _descriptionLabel;
}

-(UIButton *)leftButton{
    if(_leftButton==nil){
        _leftButton = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 40)];
        _leftButton.center = CGPointMake(self.icon.frame.origin.x/2, self.icon.center.y);
        [_leftButton setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal];
        [self.view addSubview:_leftButton];
        [_leftButton addTarget:self action:@selector(leftClick) forControlEvents:UIControlEventTouchUpInside];

    }
    return _leftButton;
}

-(UIButton *)rightButton{
    if(!_rightButton){
        _rightButton = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 40, 40)];
        _rightButton.center = CGPointMake(self.view.frame.size.width- self.icon.frame.origin.x/2, self.icon.center.y);
        [_rightButton setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal];
        [self.view addSubview:_rightButton];
        [_rightButton addTarget:self action:@selector(rightClick) forControlEvents:UIControlEventTouchUpInside];

    }
    return _rightButton;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    [self changeImage];
}

/** 改变图像数据 */
-(void)changeImage{
    
    [self.noLabel setText:[NSString stringWithFormat:@"%d/%d",self.index+1,5]];
    [self.icon setImage:[UIImage imageNamed:self.array[self.index][@"name"]]];
    [self.descriptionLabel setText:self.array[self.index][@"desc"]];
    [self.rightButton setEnabled:(self.index!=4)];
    [self.leftButton setEnabled:(self.index!=0)];
    
}
/** 左边按钮 */
-(void)leftClick{
    NSLog(@"left");
    self.index--;
    [self changeImage];
}
-(void)rightClick{
    NSLog(@"right");
    self.index++;
    [self changeImage];
}

@end