UI基础第四弹:简单的图片查看程序

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一、程序实现要求

1.要求

2. 界面分析

(1) 需要读取或修改属性的控件需要设置属性

序号标签

图片

图片描述

左边按钮

右边按钮

(2) 需要监听响应事件的对象,需要添加监听方法

左边按钮

右边按钮

二、实现基本功能的程序

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  1 //  2 //  YYViewController.m  3 //  03-图片浏览器初步  4 //  5 //  Created by apple on 14-5-21.  6 //  Copyright (c) 2014年 itcase. All rights reserved.  7 //  8   9 #import "YYViewController.h" 10  11 #define POTOIMGW    200 12 #define POTOIMGH    300 13 #define POTOIMGX    60 14 #define  POTOIMGY    50 15  16  17 @interface YYViewController () 18  19 //变量声明! 20 @property(nonatomic,strong)UILabel *firstlab; 21 @property(nonatomic,strong)UILabel *lastlab; 22 @property(nonatomic,strong)UIImageView *icon; 23 @property(nonatomic,strong)UIButton *leftbtn; 24 @property(nonatomic,strong)UIButton *rightbtn; 25  26 -(void)change; 27 @property(nonatomic ,assign)int i; 28 @end 29  30 @implementation YYViewController 31  32 - (void)viewDidLoad 33 { 34     [super viewDidLoad]; 35     self.i=0; 36     //创建一个用来显示序号的lable控件 37     UILabel *headlab=[[UILabel alloc]initWithFrame:CGRectMake(20, 10, 300, 30)]; 38      39   // [headlab setText:@"1/5"]; 40     [headlab setTextAlignment:NSTextAlignmentCenter]; 41     [headlab setTextColor:[UIColor blackColor]]; 42      43     [self.view addSubview:headlab]; 44     self.firstlab=headlab; 45      46      47      48     //创建一个装载图片的控件 49     UIImageView *potoimg=[[UIImageView alloc]initWithFrame:CGRectMake(POTOIMGX, POTOIMGY, POTOIMGW, POTOIMGH)]; 50      51     UIImage *image=[UIImage imageNamed:@"biaoqingdi"]; 52     potoimg.image=image; 53      54     [self.view addSubview:potoimg]; 55     self.icon=potoimg; 56      57      58      59     //创建最下边的描述图片的lable控件 60     UILabel *desclab=[[UILabel alloc]initWithFrame:CGRectMake(20, 400, 300, 30)]; 61    // [desclab setText:@"表情弱爆了!"]; 62     [desclab setTextAlignment:NSTextAlignmentCenter]; 63     [self.view addSubview:desclab]; 64     self.lastlab=desclab; 65      66      68     //创建两个方向键按钮 69     //设置为自定义类型 70     //1.使用类创建对象 71     UIButton *leftbtn=[UIButton buttonWithType:UIButtonTypeCustom]; 72      73     //2.设置对象的属性(不要忘记设置坐标) 74     leftbtn.frame=CGRectMake(0, self.view.center.y, 40, 40); 75     [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal]; 76     [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_highlighted"] forState:UIControlStateHighlighted]; 77      78     //3.提交对象到视图 79     [self.view addSubview:leftbtn]; 80      81     self.leftbtn=leftbtn; 82     [leftbtn addTarget:self action:@selector(leftclick:) forControlEvents:UIControlEventTouchUpInside]; 83      84      85     UIButton *rightbtn=[UIButton buttonWithType:UIButtonTypeCustom]; 86      87     rightbtn.frame=CGRectMake(POTOIMGX+POTOIMGW+10, self.view.center.y, 40, 40); 88     [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal]; 89     [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_highlighted"] forState:UIControlStateHighlighted]; 90      91     [self.view addSubview:rightbtn]; 92      93     self.rightbtn=rightbtn; 94     [rightbtn addTarget:self action:@selector(rightclick:) forControlEvents:UIControlEventTouchUpInside]; 95      96     //这是一个初始化方法,调用change可以完成初始化的工作 97     [self change]; 98 } 99 100 -(void)change101 {102     [self.firstlab setText:[NSString stringWithFormat:@"%d/5",self.i+1]];103     switch (self.i) {104         case 0:105             self.lastlab.text=@"什么表情都弱爆了!";106             self.icon.image=[UIImage imageNamed:@"biaoqingdi"];107             break;108         case 1:109             self.lastlab.text=@"病例";110             self.icon.image=[UIImage imageNamed:@"bingli"];111             break;112         case 2:113            self.lastlab.text=@"王八";114             self.icon.image=[UIImage imageNamed:@"wangba"];115             break;116         case 3:117            self.lastlab.text=@"吃牛扒";118             self.icon.image=[UIImage imageNamed:@"chiniupa"];119             break;120         case 4:121              self.lastlab.text=@"蛋疼!";122             self.icon.image=[UIImage imageNamed:@"danteng"];123             break;124     }125     //控制按钮的点击,如果为5则右键失效,如果为1,则左键失效126     self.leftbtn.enabled=(self.i!=0);127     self.rightbtn.enabled=(self.i!=4);128 129 }130 131 //向右按键132 -(void)rightclick:(UIButton *)btn133 {134     self.i++;135     [self change];136     //NSLog(@"点我了");137 }138 -(void)leftclick:(UIButton *)btn139 {140     self.i--;141     [self change];142 }143 - (void)didReceiveMemoryWarning144 {145     [super didReceiveMemoryWarning];146     // Dispose of any resources that can be recreated.147 }148 149 @end
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三、程序优化

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  1 //  2 //  YYViewController.m  3 //  03-图片浏览器初步  4 //  5 //  Created by apple on 14-5-21.  6 //  Copyright (c) 2014年 itcase. All rights reserved.  7 //  8   9 #import "YYViewController.h" 10  11 #define POTOIMGW    200 12 #define POTOIMGH    300 13 #define POTOIMGX    60 14 #define  POTOIMGY    50 15  16  17 @interface YYViewController () 18  19 //变量声明! 20 @property(nonatomic,strong)UILabel *firstlab; 21 @property(nonatomic,strong)UILabel *lastlab; 22 @property(nonatomic,strong)UIImageView *icon; 23 @property(nonatomic,strong)UIButton *leftbtn; 24 @property(nonatomic,strong)UIButton *rightbtn; 25  26 @property(nonatomic,strong)NSArray *array; 27  28 -(void)change; 29 @property(nonatomic ,assign)int i; 30 @end 31  32 @implementation YYViewController 33  34 - (void)viewDidLoad 35 { 36     [super viewDidLoad]; 37     self.i=0; 38     //创建一个用来显示序号的lable控件 39     UILabel *headlab=[[UILabel alloc]initWithFrame:CGRectMake(20, 10, 300, 30)]; 40      41   // [headlab setText:@"1/5"]; 42     [headlab setTextAlignment:NSTextAlignmentCenter]; 43     [headlab setTextColor:[UIColor blackColor]]; 44      45     [self.view addSubview:headlab]; 46     self.firstlab=headlab; 47      48      49      50     //创建一个装载图片的控件 51     UIImageView *potoimg=[[UIImageView alloc]initWithFrame:CGRectMake(POTOIMGX, POTOIMGY, POTOIMGW, POTOIMGH)]; 52      53     UIImage *image=[UIImage imageNamed:@"biaoqingdi"]; 54     potoimg.image=image; 55      56     [self.view addSubview:potoimg]; 57     self.icon=potoimg; 58      59      60      61     //创建最下边的描述图片的lable控件 62     UILabel *desclab=[[UILabel alloc]initWithFrame:CGRectMake(20, 400, 300, 30)]; 63    // [desclab setText:@"表情弱爆了!"]; 64     [desclab setTextAlignment:NSTextAlignmentCenter]; 65     [self.view addSubview:desclab]; 66     self.lastlab=desclab; 67      68      69      70     //创建两个方向键按钮 71     //设置为自定义类型 72     //1.使用类创建对象 73     UIButton *leftbtn=[UIButton buttonWithType:UIButtonTypeCustom]; 74      75     //2.设置对象的属性(不要忘记设置坐标) 76     leftbtn.frame=CGRectMake(0, self.view.center.y, 40, 40); 77     [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal]; 78     [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_highlighted"] forState:UIControlStateHighlighted]; 79      80     //3.提交对象到视图 81     [self.view addSubview:leftbtn]; 82      83     self.leftbtn=leftbtn; 84     [leftbtn addTarget:self action:@selector(leftclick:) forControlEvents:UIControlEventTouchUpInside]; 85      86      87     UIButton *rightbtn=[UIButton buttonWithType:UIButtonTypeCustom]; 88      89     rightbtn.frame=CGRectMake(POTOIMGX+POTOIMGW+10, self.view.center.y, 40, 40); 90     [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal]; 91     [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_highlighted"] forState:UIControlStateHighlighted]; 92      93     [self.view addSubview:rightbtn]; 94      95     self.rightbtn=rightbtn; 96     [rightbtn addTarget:self action:@selector(rightclick:) forControlEvents:UIControlEventTouchUpInside]; 97     //放在这里的话,只会创建一次,但是这个部分和[self change];部分有很严格的顺序要求,并不人性化,可以考虑使用懒加载特性 98 //    NSDictionary *dict1=@{@"name": @"biaoqingdi",@"desc":@"什么表情都弱爆了!"}; 99 //    NSDictionary *dict2=@{@"name": @"bingli",@"desc":@"病例"};100 //    NSDictionary *dict3=@{@"name": @"wangba",@"desc":@"乌龟"};101 //    NSDictionary *dict4=@{@"name": @"chiniupa",@"desc":@"吃牛扒"};102 //    NSDictionary *dict5=@{@"name": @"danteng",@"desc":@"蛋疼"};103 //    104 //    self.array=@[dict1,dict2,dict3,dict4,dict5];105     //这是一个初始化方法,调用change可以完成初始化的工作106     [self change];107 }108 109 -(void)change110 {111     //每次调用都需要创建?有没有什么解决办法?112 //    NSDictionary *dict1=@{@"name": @"biaoqingdi",@"desc":@"什么表情都弱爆了!"};113 //    NSDictionary *dict2=@{@"name": @"bingli",@"desc":@"病例"};114 //    NSDictionary *dict3=@{@"name": @"wangba",@"desc":@"乌龟"};115 //    NSDictionary *dict4=@{@"name": @"chiniupa",@"desc":@"吃牛扒"};116 //    NSDictionary *dict5=@{@"name": @"danteng",@"desc":@"蛋疼"};117 //    118 //    NSArray *array=@[dict1,dict2,dict3,dict4,dict5];119     120     121     //设置照片122     //先根据self.i取出数组中的元素,再取出元素(字典)中键值对应的值123 //    self.icon.image=[UIImage imageNamed:array[self.i][@"name"]];124 //    self.lastlab.text=array[self.i][@"desc"];125    // NSLog(@"%@",array[self.i][@"desc"]);126     127     self.icon.image=[UIImage imageNamed:self.array[self.i][@"name"]];128     self.lastlab.text=self.array[self.i][@"desc"];129     130     [self.firstlab setText:[NSString stringWithFormat:@"%d/5",self.i+1]];131     132 //    switch (self.i) {133 //        case 0:134 //            self.lastlab.text=@"什么表情都弱爆了!";135 //            self.icon.image=[UIImage imageNamed:@"biaoqingdi"];136 //            break;137 //        case 1:138 //            self.lastlab.text=@"病例";139 //            self.icon.image=[UIImage imageNamed:@"bingli"];140 //            break;141 //        case 2:142 //           self.lastlab.text=@"王八";143 //            self.icon.image=[UIImage imageNamed:@"wangba"];144 //            break;145 //        case 3:146 //           self.lastlab.text=@"吃牛扒";147 //            self.icon.image=[UIImage imageNamed:@"chiniupa"];148 //            break;149 //        case 4:150 //             self.lastlab.text=@"蛋疼!";151 //            self.icon.image=[UIImage imageNamed:@"danteng"];152 //            break;153 //    }154     //控制按钮的点击,如果为5则右键失效,如果为1,则左键失效155     self.leftbtn.enabled=(self.i!=0);156     self.rightbtn.enabled=(self.i!=4);157 158 }159 160 //array的get方法161 -(NSArray *)array162 {163     NSLog(@"需要获取数组");164     //只实例化一次165     if (_array==nil) {166         NSLog(@"实例化数组");167         NSDictionary *dict1=@{@"name": @"biaoqingdi",@"desc":@"什么表情都弱爆了!"};168         NSDictionary *dict2=@{@"name": @"bingli",@"desc":@"病例"};169         NSDictionary *dict3=@{@"name": @"wangba",@"desc":@"乌龟"};170         NSDictionary *dict4=@{@"name": @"chiniupa",@"desc":@"吃牛扒"};171         NSDictionary *dict5=@{@"name": @"danteng",@"desc":@"蛋疼"};172         _array=@[dict1,dict2,dict3,dict4,dict5];173     }174 //    NSDictionary *dict1=@{@"name": @"biaoqingdi",@"desc":@"什么表情都弱爆了!"};175 //    NSDictionary *dict2=@{@"name": @"bingli",@"desc":@"病例"};176 //    NSDictionary *dict3=@{@"name": @"wangba",@"desc":@"乌龟"};177 //    NSDictionary *dict4=@{@"name": @"chiniupa",@"desc":@"吃牛扒"};178 //    NSDictionary *dict5=@{@"name": @"danteng",@"desc":@"蛋疼"};179     180    // _array=@[dict1,dict2,dict3,dict4,dict5];181     return _array;182 }183 184 //向右按键185 -(void)rightclick:(UIButton *)btn186 {187     self.i++;188     [self change];189 }190 191 //向左按键192 -(void)leftclick:(UIButton *)btn193 {194     self.i--;195     [self change];196 }197 198 199 - (void)didReceiveMemoryWarning200 {201     [super didReceiveMemoryWarning];202 }203 204 @end
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说明:

1> 定义控件属性,注意:属性必须是strong的,示例代码如下:

@property (nonatomic, strong) UIImageView *icon;

2> 在属性的getter方法中实现懒加载,示例代码如下:

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 1 - (UIImageView *)icon 2  3 { 4  5     if (!_icon) { 6  7         // 计算位置参数 8  9         CGFloat imageW = 200;10 11         CGFloat imageX = (320 - imageW) / 2;12 13         CGFloat imageH = 200;14 15         CGFloat imageY = 80;16 17         // 实例化图像视图18 19         _icon = [[UIImageView alloc] initWithFrame:CGRectMake(imageX, imageY, imageW, imageH)];20 21         // 将图像视图添加到主视图22 23         [self.view addSubview:_icon];24 25     }26 27     return _icon;28 29 }
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四、使用plist文件

(1)使用Plist文件的目的:将数据与代码分离

(2)加载方法:

NSString *path = [[NSBundle mainBundle] pathForResource:@"ImageData" ofType:@"plist"];

_imageList = [NSArray arrayWithContentsOfFile:path];

提示:通常在方法中出现File字眼,通常需要传递文件的全路径作为参数

(3)代码示例

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  1 //  2 //  YYViewController.m  3 //  03-图片浏览器初步  4 //  5 //  Created by apple on 14-5-21.  6 //  Copyright (c) 2014年 itcase. All rights reserved.  7 //  8   9 #import "YYViewController.h" 10  11 #define POTOIMGW    200 12 #define POTOIMGH    300 13 #define POTOIMGX    60 14 #define  POTOIMGY    50 15  16  17 @interface YYViewController () 18  19 //变量声明! 20 @property(nonatomic,strong)UILabel *firstlab; 21 @property(nonatomic,strong)UILabel *lastlab; 22 @property(nonatomic,strong)UIImageView *icon; 23 @property(nonatomic,strong)UIButton *leftbtn; 24 @property(nonatomic,strong)UIButton *rightbtn; 25  26 @property(nonatomic,strong)NSArray *array; 27  28 -(void)change; 29 @property(nonatomic ,assign)int i; 30 @end 31  32 @implementation YYViewController 33  34 - (void)viewDidLoad 35 { 36     [super viewDidLoad]; 37     self.i=0; 38     //创建一个用来显示序号的lable控件 39     UILabel *headlab=[[UILabel alloc]initWithFrame:CGRectMake(20, 10, 300, 30)]; 40      41   // [headlab setText:@"1/5"]; 42     [headlab setTextAlignment:NSTextAlignmentCenter]; 43     [headlab setTextColor:[UIColor blackColor]]; 44      45     [self.view addSubview:headlab]; 46     self.firstlab=headlab; 47      48      49      50     //创建一个装载图片的控件 51     UIImageView *potoimg=[[UIImageView alloc]initWithFrame:CGRectMake(POTOIMGX, POTOIMGY, POTOIMGW, POTOIMGH)]; 52      53     UIImage *image=[UIImage imageNamed:@"biaoqingdi"]; 54     potoimg.image=image; 55      56     [self.view addSubview:potoimg]; 57     self.icon=potoimg; 58      59     //创建最下边的描述图片的lable控件 60     UILabel *desclab=[[UILabel alloc]initWithFrame:CGRectMake(20, 400, 300, 30)]; 61    // [desclab setText:@"表情弱爆了!"]; 62     [desclab setTextAlignment:NSTextAlignmentCenter]; 63     [self.view addSubview:desclab]; 64     self.lastlab=desclab; 65      66      67     //创建两个方向键按钮 68     //设置为自定义类型 69     //1.使用类创建对象 70     UIButton *leftbtn=[UIButton buttonWithType:UIButtonTypeCustom]; 71      72     //2.设置对象的属性(不要忘记设置坐标) 73     leftbtn.frame=CGRectMake(0, self.view.center.y, 40, 40); 74     [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_normal"] forState:UIControlStateNormal]; 75     [leftbtn setBackgroundImage:[UIImage imageNamed:@"left_highlighted"] forState:UIControlStateHighlighted]; 76      77     //3.提交对象到视图 78     [self.view addSubview:leftbtn]; 79      80     self.leftbtn=leftbtn; 81     [leftbtn addTarget:self action:@selector(leftclick:) forControlEvents:UIControlEventTouchUpInside]; 82      83      84     UIButton *rightbtn=[UIButton buttonWithType:UIButtonTypeCustom]; 85      86     rightbtn.frame=CGRectMake(POTOIMGX+POTOIMGW+10, self.view.center.y, 40, 40); 87     [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_normal"] forState:UIControlStateNormal]; 88     [rightbtn setBackgroundImage:[UIImage imageNamed:@"right_highlighted"] forState:UIControlStateHighlighted]; 89      90     [self.view addSubview:rightbtn]; 91      92     self.rightbtn=rightbtn; 93     [rightbtn addTarget:self action:@selector(rightclick:) forControlEvents:UIControlEventTouchUpInside]; 94     [self change]; 95 } 96  97 -(void)change 98 { 99     self.icon.image=[UIImage imageNamed:self.array[self.i][@"name"]];100     self.lastlab.text=self.array[self.i][@"desc"];101     102     [self.firstlab setText:[NSString stringWithFormat:@"%d/5",self.i+1]];103     104     self.leftbtn.enabled=(self.i!=0);105     self.rightbtn.enabled=(self.i!=4);106 107 }108 109 //array的get方法110 -(NSArray *)array111 {112     NSLog(@"需要获取数组");113     //只实例化一次114     if (_array==nil) {115      116         NSString *path=[[NSBundle mainBundle] pathForResource:@"data" ofType:@"plist"];117         //数组的数据从文件获取118        // _array=[NSArray arrayWithContentsOfFile:path];119         _array=[[NSArray alloc]initWithContentsOfFile:path];120         //打印查看包的位置121         NSLog(@"%@",path);122         123        NSLog(@"实例化数组");124     }125 126     return _array;127 }128 129 //向右按键130 -(void)rightclick:(UIButton *)btn131 {132     self.i++;133     [self change];134 }135 136 //向左按键137 -(void)leftclick:(UIButton *)btn138 {139     self.i--;140     [self change];141 }142 143 - (void)didReceiveMemoryWarning144 {145     [super didReceiveMemoryWarning];146 }147 148 @end
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(4)plist文件

(5)实现效果

五、补充

开发思路:

1.完成基本功能

2.考虑性能

(1)(初始化操作,可以直接调用change进行)

(2)因为要控制序号和图片两个变量,所以考虑使用字典代替掉switch

(3)每次点击,字典都需要创建一次,效率地下,可以考虑创建的这部分拿到初始化方法中去,这样就只需要创建一次就ok了。

(4)考虑缺点(对代码的顺序要求极其严格)

(5)懒加载(需要的时候才加载,那么什么时候是需要的时候,及调用get方法的时候)

(6)每次都来一下?效率低下—》只有第一次调用get方法时为空,此时实例化并建立数组,其他时候直接返回成员变量(仅仅执行一次)

注意点:

1.方法的调用堆栈(顺序)。

2.使用plist:让数据的操作更加灵活,把数据弄到外面去,解除耦合性,让耦合性不要太强。实际上是一个xml,是苹果定义的一种特殊格式的xml。

3.bundle-包(只读)

     (转自播客园:文顶顶,如有冒犯请谅解,可以联系本人删除)

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