1 //  2 //  ViewController.m  3 //  12-27-UIPickerView  4 //  5 //  Created by xiaomoge on 14/12/27.  6 //  Copyright (c) 2014年 xiaomoge. All rights reserved.  7 //  8   9 #import "ViewController.h" 10  11 @interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate> 12  13 @property (nonatomic,strong)NSArray *foods; 14 //水果标签 15 @property (weak, nonatomic) IBOutlet UILabel *fruitLabel; 16 //主食标签 17 @property (weak, nonatomic) IBOutlet UILabel *mainFoodLabel; 18 //饮料标签 19 @property (weak, nonatomic) IBOutlet UILabel *drinkLabel; 20 //随机按钮事件 21 - (IBAction)randomMenu; 22 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView; 23  24 @end 25  26 @implementation ViewController 27  28 #pragma mark - 懒加载 29 -(NSArray *)foods{ 30     if (!_foods) { 31         NSString *filePath = [[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil]; 32         _foods = [NSArray arrayWithContentsOfFile:filePath]; 33     } 34     return _foods; 35 } 36  37 - (void)viewDidLoad { 38     [super viewDidLoad]; 39      40     //默认选中数据，第一行数据 41     NSInteger columns = self.foods.count; 42     for (int i = 0; i < columns; i++) { 43         [self pickerView:nil didSelectRow:0 inComponent:i]; 44     } 45 } 46 #pragma mark - UIPickerView数据源 47 //列数 48 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{ 49     return self.foods.count; 50 } 51 //每一列的行数 52 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{ 53     //获取每一列的数据 54     NSArray *items = self.foods[component]; 55     //返回每一列的个数 56     return items.count; 57 } 58 #pragma mark - UIPickerView代理 59 -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{ 60     //获取每一列的数据 61     NSArray *items = self.foods[component]; 62     //返回对应列的行的数据 63     return items[row]; 64 } 65 #pragma mark - pickerView的选中方法 66 -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{ 67     //获取数据 68     NSArray *items = self.foods[component]; 69     NSString *rowStr = items[row]; 70     //更改数据 71     switch (component) { 72         case 0://水果 73             self.fruitLabel.text = rowStr; 74             break; 75         case 1://主食 76             self.mainFoodLabel.text = rowStr; 77             break; 78         case 2://饮料 79             self.drinkLabel.text = rowStr; 80             break; 81         default: 82             break; 83     } 84 } 85 #pragma mark 随机菜单，由天决定我们吃什么 86 - (IBAction)randomMenu { 87     //获取每列有多少行 88     NSInteger columns = self.foods.count; 89      90     for (int i = 0; i < columns; i ++) { 91         NSArray *items = self.foods[i]; 92         //对应列的行数 93         NSInteger rowsInColumn = items.count; 94         //在行范围产生随机数据 95         NSInteger randomRow =arc4random_uniform((int)rowsInColumn); 96         // 获取旧的行数 97         NSInteger oldRow = [self.pickerView selectedRowInComponent:i]; 98          99         while (oldRow == randomRow ) {100             randomRow =arc4random_uniform((int)rowsInColumn);//如果随机出来的数据和旧数据相同，那么继续进行随机101         }102         //更改label的数据103         [self pickerView:nil didSelectRow:randomRow inComponent:i];104         //更改UIPickerView选中的数据105         [self.pickerView selectRow:randomRow inComponent:i animated:YES];106     }107 }108 @end

1 - (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated;