ios中 pickerView的用法

今天是一个特殊的日子（Mac pro 敲的 爽。。。 昨天到的）

//
//  QRViewController.m//

#import "QRViewController.h"

@interface QRViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>
@property (weak, nonatomic) IBOutlet UILabel *fruitLable;//水果
@property (weak, nonatomic) IBOutlet UILabel *mainLabel;//主菜
@property (weak, nonatomic) IBOutlet UILabel *drinkLabel;//饮料
@property (nonatomic,strong) NSArray *foods;
@property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
- (IBAction)ranDom;

@end

@implementation QRViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    for (int i=0; i<self.foods.count; i++) {
        [self pickerView:nil didSelectRow:0 inComponent:i];
    }
    //[self pickerView:nil didSelectRow:0 inComponent:0];
    //[self pickerView:nil didSelectRow:0 inComponent:1];
    //[self pickerView:nil didSelectRow:0 inComponent:2];
}
/**
 *懒加载数据
 */
- (NSArray *)foods
{
    if(_foods==nil){
        NSString *path=[[NSBundle mainBundle] pathForResource:@"foods" ofType:@"plist"];
        NSArray *arraylist=[NSArray arrayWithContentsOfFile:path];
        _foods=arraylist;
    }
    return _foods;
}
#pragma mark   -数据源方法
/**
 *一共多少列
 */
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return self.foods.count;
}
/**
 * 某一列显示多少行
 */
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    NSArray *subfoods=self.foods[component];
    return subfoods.count;
}

#pragma mark - 代理方法
/**
 *某一列中的某一行显示的数据
 */
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    return self.foods[component][row];
}
/**
 *选中某一行一列
 */
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    if(component==0){//水果
        self.fruitLable.text=self.foods[component][row];
    }else if(component==1){//主菜
        self.mainLabel.text=self.foods[component][row];
    }else if(component==2){//饮料
        self.drinkLabel.text=self.foods[component][row];
    }
}
/**
 *随机生成一个
 */
- (IBAction)ranDom {
    for (int i=0; i<self.foods.count; i++) {
        //每一行的总长度
        int count=[self.foods[i] count];
        //生成一个随机数
        int row=arc4random()%count;
        //设置pickerView选中的列的行
        [self.pickerView selectRow:row inComponent:i animated:YES];
        //设置Label的文字
        [self pickerView:nil didSelectRow:row inComponent:i];
    }
    
}

@end