IOS第11天(3:UIPickerView省市联动)

*********

#import "ViewController.h"
#import "Province.h"

@interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>

@property (nonatomic,strong)NSArray *provinces;


@property (nonatomic,assign)NSInteger indexOfProvice;//当前默认选中的省份
@end



@implementation ViewController


-(NSArray *)provinces{
    if (!_provinces) {
        _provinces = [Province provinceList];
    }
    
    return _provinces;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    NSLog(@"%@",self.provinces);
}


// returns the number of 'columns' to display.
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 2;
}

// returns the # of rows in each component..
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    
    if (component == 0) {//省分
        return self.provinces.count;
    }

    
    //获取对应省份的城市个数
    Province *province = self.provinces[self.indexOfProvice];
    
    return province.cities.count;

}

#pragma mark 显示数据
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    
    
    
    if(component == 0){//显示省份的名字
        //对应列行的省份
        Province *province = self.provinces[row];
        return province.name;
    }
    
    //获取选中的城市，显示城市名字
    Province *selectedProvice = self.provinces[self.indexOfProvice];
    return selectedProvice.cities[row];
}

//-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
//    
//    UILabel *label = (UILabel *)view;
//    if (!label) {
//        label = [[UILabel alloc] init];
//    }
//    
//    if(component == 0){//显示省份的名字
//        //对应列行的省份
//        Province *province = self.provinces[row];
//        label.text =  province.name;
//        label.backgroundColor = [UIColor grayColor];
//    }else{
//        
//        //获取选中的城市，显示城市名字
//        Province *selectedProvice = self.provinces[self.indexOfProvice];
//        label.text = selectedProvice.cities[row];
//        label.backgroundColor = [UIColor blueColor];
//    }
//    
//    
//    
//    
//    return label;
//}


#pragma mark 选中行

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
    
    if (component == 0) {//第一列省的选中改变后，就要更新第二列数据
        //更新选中省份的索引
        self.indexOfProvice = row;
        
        //刷新数据
        //全部刷新
        //[pickerView reloadAllComponents];
        
        //部份刷新
        [pickerView reloadComponent:1];
        
        //不管之前第二列选中第几行，重新刷新数据后，都显示每二列的第一行
        [pickerView selectRow:0 inComponent:1 animated:YES];
    }
}

#pragma mark 设置宽度
-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component{
    if (component == 0) {
        return 80;
    }
    
    return 200;
}

@end

***model.m

#import "Province.h"

@implementation Province


-(instancetype)initWithDict:(NSDictionary *)dict{
    if (self = [super init]) {
        [self setValuesForKeysWithDictionary:dict];
    }
    
    return self;
}
+(instancetype)provinceWithDict:(NSDictionary *)dict{
    return [[self alloc] initWithDict:dict];
}

+(NSArray *)provinceList{
    //plist文件路径
    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"provinces.plist" ofType:nil];
    NSArray *provincePlist = [NSArray arrayWithContentsOfFile:filePath];
    
    NSMutableArray *provinceM = [NSMutableArray array];
    for (NSDictionary *dic in provincePlist) {
        Province *prov = [Province provinceWithDict:dic];
        [provinceM addObject:prov];
    }
    
    return provinceM;

}
@end

****model.h

#import <UIKit/UIKit.h>

@interface Province : NSObject

@property(nonatomic,copy)NSString *name;
@property(nonatomic,strong)NSArray *cities;

-(instancetype)initWithDict:(NSDictionary *)dict;
+(instancetype)provinceWithDict:(NSDictionary *)dict;


+(NSArray *)provinceList;

@end