OC学习之UI笔记二

UIView控件字典懒加载1.UIView控件 用来显示图片 显示图片的方法 UIImage *image=[UIImage ImageNamed:@”图片名”];Self.uimage.view=image;2.字典字典有两种：NSdictionary（静态）和NSMUtabledictionary（动态）NSMutabledictionary *dictionary=[NSMutabledictionary dictionary]Dict[@”icon”]=@”值”;Dict[@”desc”=@”值”;3.懒加载 为了优化性能。实际上是改写get方法当发现没有数据时才开始加载数据。4.If(_images==nil){数据的初始化}Return _images;////  ViewController.m//  03-图片浏览器////  Created by feiyue on 17/4/24.//  Copyright © 2017年 HCSLiujing. All rights reserved.//#import "ViewController.h"@interface ViewController ()- (IBAction)preVious;- (IBAction)next;@property(nonatomic,assign)int index;@property (weak, nonatomic) IBOutlet UILabel *NOLabel;@property (weak, nonatomic) IBOutlet UIImageView *head;@property (weak, nonatomic) IBOutlet UILabel *descLabel;@property (weak, nonatomic) IBOutlet UIButton *btnPre;@property (weak, nonatomic) IBOutlet UIButton *btnNext;//放置数据//一般对象用strong,UI控件用weak@property(nonatomic,strong)NSArray *images;@end@implementation ViewController- (void)viewDidLoad {    //可变字典        //为了性能问题使用了懒加载 //    NSMutableDictionary *dict1=[NSMutableDictionary dictionary];//    dict1[@"icon"]=@"biaoqingdi";//    dict1[@"desc"]=@"No1";//    NSMutableDictionary *dict2=[NSMutableDictionary dictionary];//    dict2[@"icon"]=@"wangba";//    dict2[@"desc"]=@"No2";//    NSMutableDictionary *dict3=[NSMutableDictionary dictionary];//    dict3[@"icon"]=@"bingli";//    dict3[@"desc"]=@"No3";//    NSMutableDictionary *dict4=[NSMutableDictionary dictionary];//    dict4[@"icon"]=@"chiniupa";//    dict4[@"desc"]=@"No4";//    NSMutableDictionary *dict5=[NSMutableDictionary dictionary];//    dict5[@"icon"]=@"danteng";//    dict5[@"desc"]=@"No5";//    _images=@[dict1,dict2,dict3,dict4,dict5];   /** [super viewDidLoad];   self.NOLabel.text=@"1/5";    self.head.image=[UIImage imageNamed:@"biaoqingdi"];    self.descLabel.text=@"No1";    */            [self changData];        }// 懒加载:重写get方法//核心思想：当数据不存在的时候加载-(NSArray *)images{    if (_images==nil) {//数据不存在的时候加载        NSMutableDictionary *dict1=[NSMutableDictionary dictionary];        dict1[@"icon"]=@"biaoqingdi";        dict1[@"desc"]=@"No1";        NSMutableDictionary *dict2=[NSMutableDictionary dictionary];        dict2[@"icon"]=@"wangba";        dict2[@"desc"]=@"No2";        NSMutableDictionary *dict3=[NSMutableDictionary dictionary];        dict3[@"icon"]=@"bingli";        dict3[@"desc"]=@"No3";        NSMutableDictionary *dict4=[NSMutableDictionary dictionary];        dict4[@"icon"]=@"chiniupa";        dict4[@"desc"]=@"No4";        NSMutableDictionary *dict5=[NSMutableDictionary dictionary];        dict5[@"icon"]=@"danteng";        dict5[@"desc"]=@"No5";        _images=@[dict1,dict2,dict3,dict4,dict5];    }    return _images;}- (IBAction)preVious {    //索引值减一    self.index--;       [self changData];}- (IBAction)next {    //1,索引值加一    //self.index=self.index+1;    self.index++;    //2.根据索引值设置数据    [self changData];}-(void)changData{    self.NOLabel.text=[NSString stringWithFormat:@"%d/%d",self.index+1,  self.images.count];            NSDictionary *dict= self.images[self.index];    self.head.image=[UIImage imageNamed:dict[@"icon"]];    self.descLabel.text=dict[@"desc"];    //2.根据索引值设置数据  /**  switch (self.index) {        case 0:                       self.head.image=[UIImage imageNamed:@"biaoqingdi"];            self.descLabel.text=@"表情1";            break;                    case 1:                        self.head.image=[UIImage imageNamed:@"wangba"];            self.descLabel.text=@"表情2";            break;  case 2:                        self.head.image=[UIImage imageNamed:@"bingli"];            self.descLabel.text=@"表情3";            break;  case 3:                       self.head.image=[UIImage imageNamed:@"chiniupa"];            self.descLabel.text=@"表情4";            break;  case 4:            //self.NOLabel.text=@"5/5";            self.head.image=[UIImage imageNamed:@"danteng"];            self.descLabel.text=@"表情5";            break;    }   */    //设置按钮状态         /**  if (self.index==0) {        self.btnPre.enabled=NO;            }else{        self.btnPre.enabled=YES;    }*/    self.btnPre.enabled=(self.index==0)?NO:YES;       /** if (self.index==4) {        self.btnNext.enabled=NO;    }else{                self.btnNext.enabled=YES;            }*/    self.btnNext.enabled=(self.index==self.images.count-1)?NO:YES;}@end