首页 > 代码库 > [iOS基础控件 - 6.10.1] PickerView 餐点搭配Demo
[iOS基础控件 - 6.10.1] PickerView 餐点搭配Demo
A.需求
1.使用PickerView做出有3列餐点（水果、主菜、饮料）的搭配Demo
2.选择的餐点实时显示在“显示区”
3.提供“随机”按钮，随机选择菜品搭配
B.实现步骤
1.拖入一个PickerView
2.用控制器配置dataSource和delegate
1 // 遵守UIPickerViewDataSource,UIPickerViewDelegate 2 @interface ViewController () <UIPickerViewDataSource, UIPickerViewDelegate> 3 4 /** 选择器 */ 5 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView; 6 7 @end 8 9 @implementation ViewController10 11 - (void)viewDidLoad {12 [super viewDidLoad];13 // Do any additional setup after loading the view, typically from a nib.14 15 // 设置dataSource16 self.pickerView.dataSource = self;17 // 设置delegage18 self.pickerView.delegate = self;19 }
3.实现代理方法
1 #pragma mark - 代理方法 2 /** 列数 */ 3 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { 4 return 3; 5 } 6 7 /** 对应列的行数 */ 8 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { 9 return 5;10 }11 12 /** 对应列和行的显示内容 */13 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {14 return @"内容";15 }
4.引入plist文件，读取数据
1 /** 加载数据，延迟加载 */ 2 - (NSArray *) foodCategories { 3 if (nil == _foodCategories) { 4 _foodCategories = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil]]; 5 } 6 7 return _foodCategories; 8 } 9 10 #pragma mark - dataSource方法11 /** 列数 */12 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {13 return self.foodCategories.count;14 }15 16 /** 对应列的行数 */17 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {18 NSArray *foods = self.foodCategories[component];19 return foods.count;20 }21 22 23 #pragma mark - delegate方法24 /** 对应列和行的显示内容 */25 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {26 NSArray *foods = self.foodCategories[component];27 return foods[row];28 }
5.制作显示区
1 /** 水果 */2 @property (weak, nonatomic) IBOutlet UILabel *fruitLabel;3 /** 主菜 */4 @property (weak, nonatomic) IBOutlet UILabel *mainLabel;5 /** 饮料 */6 @property (weak, nonatomic) IBOutlet UILabel *drinkLabel;
6.响应选择事件
1 /** 响应选择餐点事件 */ 2 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { 3 NSArray *foods = self.foodCategories[component]; 4 NSString *food = foods[row]; 5 6 switch (component) { 7 case 0: 8 self.fruitLabel.text = food; 9 break;10 case 1:11 self.mainLabel.text = food;12 break;13 case 2:14 self.drinkLabel.text = food;15 break;16 default:17 break;18 }
7.制作“随机”功能
1 /** 随机选择餐点 */ 2 - (IBAction)onRandomClicked { 3 // 循环所有餐点种类 4 for (int i=0; i<self.foodCategories.count; i++) { 5 // 之前选择的餐点行数 6 NSInteger originalRow = [self.pickerView selectedRowInComponent:i]; 7 8 NSInteger row = originalRow; 9 10 // 此种类内含有的所有餐点11 NSArray *foods = self.foodCategories[i];12 // 如果随机的餐点跟上一次的相同，继续随机13 while (row == originalRow) {14 row = arc4random() % foods.count;15 }16 17 // 通知pickerView改变选择18 [self.pickerView selectRow:row inComponent:i animated:YES];19 20 // 改变显示区21 [self pickerView:self.pickerView didSelectRow:row inComponent:i];22 }23 }
[iOS基础控件 - 6.10.1] PickerView 餐点搭配Demo
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