(素材源码)猫猫学IOS（二十）UI之UIPickerView_点菜系统

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素材代码地址：http://download.csdn.net/detail/u013357243/8596279
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地址：http://blog.csdn.net/u013357243?viewmode=contents

先看效果图 ##

代码

////  NJViewController.m//  01-点菜////  Created by apple on 14-6-3.//  Copyright (c) 2014年 heima. All rights reserved.//#import "NJViewController.h"@interface NJViewController ()<UIPickerViewDataSource, UIPickerViewDelegate>@property (weak, nonatomic) IBOutlet UIPickerView *pickerView;/** *  随机按钮点击事件 */- (IBAction)randomFood:(UIButton *)sender;/** *  所有食物 */@property (nonatomic, strong) NSArray *foods;/** *  水果 */@property (weak, nonatomic) IBOutlet UILabel *fruitLabel;/** *  主菜 */@property (weak, nonatomic) IBOutlet UILabel *stapleLabel;/** *  饮料 */@property (weak, nonatomic) IBOutlet UILabel *drinkLabel;@end@implementation NJViewController- (void)viewDidLoad{    [super viewDidLoad];    // 设置默认选中的内容//    self.fruitLabel.text = self.foods[0][0];//    self.stapleLabel.text = self.foods[1][0];//    self.drinkLabel.text = self.foods[2][0];//    [self pickerView:nil didSelectRow:0 inComponent:0];//    [self pickerView:nil didSelectRow:0 inComponent:1];//    [self pickerView:nil didSelectRow:0 inComponent:2];    for (int component = 0; component < self.foods.count; component++) {        [self pickerView:nil didSelectRow:0 inComponent:component];    }}#pragma mark - UIPickerViewDataSource// 返回pickerView一共有多少列- (NSInteger) numberOfComponentsInPickerView:(UIPickerView *)pickerView{//    return 3;    return self.foods.count;}// 返回pickerView的第component列有多少行- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{//    return 4;    // 1.获取对应列的数组    NSArray *subFoods = self.foods[component];    // 2.返回对应列的行数    return subFoods.count;}#pragma mark - UIPickerViewDelegate// 返回第component列的第row行显示什么内容- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{    // 1.获取对应列的数组    NSArray *subFoods = self.foods[component];    // 2.获取对应行的标题    NSString *name = subFoods[row];    return name;}// 当选中了pickerView的某一行的时候调用// 会将选中的列号和行号作为参数传入// 只有通过手指选中某一行的时候才会调用- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{//    NSLog(@"component = %d, row = %d", component, row);    // 1.获取对应列对应行的数据    NSString *name = self.foods[component][row];//    NSLog(@"name = %@", name);    // 2.判断选择的是哪一列, 根据列号设置对应的数据    if (0 == component) {        // 水果        self.fruitLabel.text = name;    }else if (1 == component)    {        // 主菜        self.stapleLabel.text = name;    }else    {        // 饮料        self.drinkLabel.text = name;    }}#pragma mark - 懒加载- (NSArray *)foods{    if (_foods == nil) {        NSString *fullPath = [[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil];        _foods = [NSArray arrayWithContentsOfFile:fullPath];    }    return _foods;}#pragma mark - 监听按钮点击- (IBAction)randomFood:(UIButton *)sender {    // 让pickerView主动选中某一行    // 让pickerView选中inComponent列的Row行//    [self.pickerView selectRow:1 inComponent:0 animated:YES];    /*    [self.pickerView selectRow: arc4random() % 12 inComponent:0 animated:YES];     [self.pickerView selectRow: arc4random() % 15 inComponent:1 animated:YES];     [self.pickerView selectRow: arc4random() % 10 inComponent:2 animated:YES];     *///    [self.foods objectAtIndex:0]; == self.foods[0];//    [self.foods[0] count];    /*    // 根据每一列的元素个数生成随机值    [self.pickerView selectRow: arc4random() % [self.foods[0] count] inComponent:0 animated:YES];    [self.pickerView selectRow: arc4random() % [self.foods[1] count] inComponent:1 animated:YES];    [self.pickerView selectRow: arc4random() % [self.foods[2] count] inComponent:2 animated:YES];    */    for (int component = 0; component < self.foods.count; component++) {        // 获取对应列的数据总数        int total = [self.foods[component] count];        // 根据每一列的总数生成随机数(当前生成的随机数)        int randomNumber = arc4random() % total;        // 获取当前选中的行(上一次随机后移动到的行)        int oldRow =  [self.pickerView selectedRowInComponent:0];//        NSLog(@"oldRow = %d", oldRow);        // 比较上一次的行号和当前生成的随机数是否相同, 如果相同重新生成        while (oldRow == randomNumber) {            randomNumber = arc4random() % total;        }        // 让pickerview滚动到某一行        [self.pickerView selectRow: randomNumber inComponent:component animated:YES];        // 通过代码选中某一行        [self pickerView:nil didSelectRow:randomNumber inComponent:component];    }}@end

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翟乃玉的博客
地址：http://blog.csdn.net/u013357243?viewmode=contents