iOS开发UI篇—使用picker View控件完成一个简单的选餐应用

  1 //
  2 //  YYViewController.m
  3 //  06-简单选菜系统的实现
  4 //
  5 //  Created by apple on 14-6-5.
  6 //  Copyright (c) 2014年 itcase. All rights reserved.
  7 //
  8 
  9 #import "YYViewController.h"
 10 
 11 //遵守数据源和代理协议
 12 @interface YYViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>
 13 /**
 14  *  水果
 15  */
 16 @property (strong, nonatomic) IBOutlet UILabel *fruitLab;
 17 /**
 18  *  主菜
 19  */
 20 @property (strong, nonatomic) IBOutlet UILabel *stapleLab;
 21 /**
 22  *  饮料
 23  */
 24 @property (strong, nonatomic) IBOutlet UILabel *drinkLab;
 25 /**
 26  *  保存所有的数据
 27  */
 28 @property(nonatomic,strong)NSArray *foods;
 29 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
 30 - (IBAction)randomFood:(id)sender;
 31 
 32 @end
 33 
 34 @implementation YYViewController
 35 
 36 - (void)viewDidLoad
 37 {
 38     [super viewDidLoad];
 39     
 40     //在这里设置下方数据刷新部分的初始显示
 41     for (int component = 0; component<self.foods.count; component++) {
 42         [self pickerView:nil didSelectRow:0 inComponent:component];
 43     }
 44 }
 45 
 46 #pragma mark-使用懒加载，把数据信息加载进来
 47 -(NSArray *)foods
 48 {
 49     if (_foods==nil) {
 50         NSString *fullpath=[[NSBundle mainBundle]pathForResource:@"foods.plist" ofType:nil];
 51         NSArray *arrayM=[NSArray arrayWithContentsOfFile:fullpath];
 52         _foods=arrayM;
 53     }
 54     return _foods;
 55 }
 56 
 57 #pragma mark-处理随机按钮的点击事件
 58 - (IBAction)randomFood:(id)sender {
 59     
 60     // 让pickerView主动选中某一行
 61     // 让pickerView选中inComponent列的Row行
 62     //    [self.pickerView selectRow:1 inComponent:0 animated:YES];
 63     
 64     /*
 65      [self.pickerView selectRow: arc4random() % 12 inComponent:0 animated:YES];
 66      [self.pickerView selectRow: arc4random() % 15 inComponent:1 animated:YES];
 67      [self.pickerView selectRow: arc4random() % 10 inComponent:2 animated:YES];
 68      */
 69     
 70     //    [self.foods objectAtIndex:0]; == self.foods[0];
 71     //    [self.foods[0] count];
 72     
 73     /*
 74      // 根据每一列的元素个数生成随机值
 75      [self.pickerView selectRow: arc4random() % [self.foods[0] count] inComponent:0 animated:YES];
 76      [self.pickerView selectRow: arc4random() % [self.foods[1] count] inComponent:1 animated:YES];
 77      [self.pickerView selectRow: arc4random() % [self.foods[2] count] inComponent:2 animated:YES];
 78      */
 79     
 80     //设置一个随机数
 81     for (int component=0; component<self.foods.count; component++) {
 82         //获取当前列对应的数据元素的个数
 83         int total=[self.foods[component] count];
 84         //根据每一列的总数生成随机数（当前生成的随机数）
 85         int randomNumber=arc4random()%total;
 86         
 87         //获取当前选中的行（上一次随机后移动到的行）
 88         int oldRow=[self.pickerView selectedRowInComponent:0];
 89         
 90         //比较上一次的行号和当前生成的随机数是否相同，如果相同的话则重新生成
 91         while (oldRow==randomNumber) {
 92                 randomNumber=arc4random()%total;
 93         }
 94         
 95         //让pickerview滚动到指定的某一行
 96         [self.pickerView selectRow:randomNumber inComponent:component animated:YES];
 97         //模拟，通过代码选中某一行
 98         [self pickerView:nil didSelectRow:randomNumber inComponent:component];
 99     }
100 }
101 
102 #pragma mark- 设置数据
103 //一共多少列
104 -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
105 {
106     return self.foods.count;
107 }
108 
109 //每列对应多少行
110 -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
111 {
112     //1.获取当前的列
113     NSArray *arayM= self.foods[component];
114     //2.返回当前列对应的行数
115     return arayM.count;
116 }
117 
118 //每列每行对应显示的数据是什么
119 -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
120 {
121     //1.获取当前的列
122     NSArray *arayM= self.foods[component];
123     //2.获取当前列对应的行的数据
124     NSString *name=arayM[row];
125     return name;
126 }
127 
128 #pragma mark-设置下方的数据刷新
129 // 当选中了pickerView的某一行的时候调用
130 // 会将选中的列号和行号作为参数传入
131 // 只有通过手指选中某一行的时候才会调用
132 -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
133 {
134     //获取对应列，对应行的数据
135     NSString *name=self.foods[component][row];
136     //赋值
137     if (0==component) {
138         self.fruitLab.text=name;
139     }else if(1==component)
140     {
141         self.stapleLab.text=name;
142     }else
143         self.drinkLab.text=name;
144 }
145 
146 #pragma mark-隐藏状态栏
147 -(BOOL)prefersStatusBarHidden
148 {
149     return YES;
150 }
151 @end