UIPicker city.plist(实例)

前言： UIPickerView 是一个选择器控件， 它可以生成单列的选择器，也可生成多列的选择器，而且开发者完全可以自定义选择项的外观，因此用法非常灵活。UIPickerView 直接继承了 UIView ，没有继承 UIControl ，因此，它不能像 UIControl 那样绑定事件处理方法， UIPickerView 的事件处理由其委托对象完成。

Interface Builder只支持为UIPickerView设置一个属性——Shows Selection Indicator，该属性用于控制是否显示UIPickerView中的选中标记（以高亮背景作为选中标记）。

 

 

@property(strong,nonatomic) UIPickerView *picker;
@property(strong,nonatomic) NSMutableArray *sheng;
@property(strong,nonatomic) NSMutableArray *shi;

@property(strong,nonatomic) NSArray *array;

 

 

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.sheng=[NSMutableArray array];
    self.shi=[NSMutableArray array];
    NSBundle *bundle=[NSBundle mainBundle];

    NSString *path=[bundle pathForResource:@"city.plist" ofType:nil];

    self.array=[NSArray arrayWithContentsOfFile:path];

 

 

    for (NSDictionary *ar1 in self.array) {

 

 

        NSArray *ar2=[ar1 objectForKey:@"Cities"];
        [self.sheng addObject:[ar1 objectForKey:@"State"]];
        for (NSDictionary *ar3 in ar2) {
//            NSLog(@"%@",[ar3 objectForKey:@"city"]);
        [self.shi addObject:[ar3 objectForKey:@"city"]];
           
        }
       
       
    }

    self.picker=[[UIPickerView alloc]initWithFrame:CGRectMake(0, 200, 414, 300)];
    self.picker.backgroundColor=[UIColor greenColor];
   
    [self.view addSubview: self.picker];
    self.picker.delegate=self;
    self.picker.dataSource=self;
   
}

#pragma mark -数据源  nubertOfComponentsInPickerView:
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 2;
}

#pragma mark - 数据源 pickerView: attributedTitleForRow: forComponent:
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
   
 
   
    if (component==0) {
        return self.sheng.count;
    }
         return self.shi.count;
}


#pragma mark - 显示信息方法  delegate
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    if (component==0) {
        return self.sheng[row];
       
    }
   
  
         return self.shi[row];
}
#pragma mark -选中行的信息
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    if (component==0) {
        //清除上次选择地城市
        [self.shi removeAllObjects];
        NSDictionary *dic=[self.array objectAtIndex:row];
//          NSLog(@"%@",dic);
        NSArray *arr1=dic[@"Cities"];
     

        NSMutableArray * arr2 =[NSMutableArray array];
        for (NSDictionary * dic in arr1) {
            [arr2 addObject:dic[@"city"]];
           
          
        }
        self.shi=arr2;
        [self.picker selectRow:row inComponent:0 animated:YES];
       
        [self.picker reloadComponent:1];
       
        }
    else {
        NSInteger firstRow=[self.picker selectedRowInComponent: 0];
        NSInteger secondRow=[self.picker selectedRowInComponent:1];
       
        NSString *firstString=[self.sheng objectAtIndex:firstRow];
        NSString *secondString=[self.shi objectAtIndex:secondRow];
       
       
        NSString *message=[NSString stringWithFormat:@"您确定要选择%@%@吗？",firstString,secondString];
        UIAlertController *alertMessage=[UIAlertController alertControllerWithTitle:@"提示" message:message preferredStyle:UIAlertControllerStyleAlert];
       
        UIAlertAction *cancle=[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
       
        UIAlertAction *ok=[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:nil];
       
        [alertMessage addAction:cancle];
        [alertMessage addAction:ok];
        [self presentViewController:alertMessage animated:YES completion:nil];
        NSLog(@"%@%@",firstString,secondString);

    }
   
       
    }

   

#pragma mark - 行高
-(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
    if (component==0) {
         return  80;
    }
    return 50;

}