IOS学习之UIPickerView控件的关联选择

接上篇IOS学习之UIPickerView控件的简单使用 

接着上篇的代码 http://download.csdn.net/detail/totogo2010/4391870 ，我们要实现的效果如下：

当选择左边的一级选项时，左边展示一级选项里含有的二级选项，选择后显示在TextField里。

如何实现呢？建立一个和左边的列表key对应的数组，当选择这个key时，刷新左边UIPickerView部分的内容显示对应数组的数据，选择时，找到

两个UIPickerView部件rowIndex，找出数据，放到TextField里。

1、打开上篇PickerViewDemo项目，在ViewController.h添加两个成员变量：NSArray *subPickerArray; NSDictionary *dicPicker;

#import <UIKit/UIKit.h> @interface ViewController : UIViewController<UIPickerViewDelegate, UITextFieldDelegate,UIPickerViewDataSource> { NSArray *pickerArray; NSArray *subPickerArray; NSDictionary *dicPicker; } - (IBAction)selectButton:(id)sender; @property (strong, nonatomic) IBOutlet UIToolbar *doneToolbar; @property (strong, nonatomic) IBOutlet UIPickerView *selectPicker; @property (strong, nonatomic) IBOutlet UITextField *textField; @end

2、初始化

- (void)viewDidLoad { [super viewDidLoad]; pickerArray = [NSArray arrayWithObjects:@"动物",@"植物",@"石头", nil]; dicPicker = [NSDictionary dictionaryWithObjectsAndKeys: [NSArray arrayWithObjects:@"鱼",@"鸟",@"虫子", nil], @"动物", [NSArray arrayWithObjects:@"花",@"草",@"葵花", nil], @"植物", [NSArray arrayWithObjects:@"疯狂的石头",@"花岗岩",@"鹅卵石", nil], @"石头",nil]; subPickerArray = [dicPicker objectForKey:@"动物"]; textField.inputView = selectPicker; textField.inputAccessoryView = doneToolbar; textField.delegate = self; selectPicker.delegate = self; selectPicker.dataSource = self; selectPicker.frame = CGRectMake(0, 480, 320, 216); }

给 NSDictionary *dicPicker;赋值，对应的三个关键字添加了对应的数组。

3、Component返回两个，这样就有两个齿轮了。

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{ return 2; }

4、使用宏

在#import "ViewController.h"下面定义两个宏，代表UIPickerView齿轮的左边的部分和右边的部分。左边的部分是0，右边的是1.

#import "ViewController.h"

#define kFirstComponent 0

#define kSubComponent 1

5、判断是那个齿轮，返回相应的数据的Count。

-(NSInteger) pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{ if(component == kFirstComponent){ return [pickerArray count]; }else { return [subPickerArray count]; } }

6、根据component返回相应的String数据

-(NSString*) pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{ if(component == kFirstComponent){ return [pickerArray objectAtIndex:row]; }else { return [subPickerArray objectAtIndex:row]; } }

7、拖动左边的齿轮时，右边的数据相应的Reload更新。

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{ if (component == kFirstComponent) { subPickerArray = [dicPicker objectForKey:[pickerArray objectAtIndex:row]]; [pickerView selectRow:0 inComponent:kSubComponent animated:YES]; [pickerView reloadComponent:kSubComponent]; } }

8、相应选择的数据，并显示在TextField上。

-(void)textFieldDidEndEditing:(UITextField *)textField{ NSInteger firstViewRow = [selectPicker selectedRowInComponent:kFirstComponent]; NSInteger subViewRow = [selectPicker selectedRowInComponent:kSubComponent]; NSString * firstString = [pickerArray objectAtIndex:firstViewRow]; NSString * subString = [[dicPicker objectForKey:[pickerArray objectAtIndex:firstViewRow]] objectAtIndex:subViewRow] ; NSString *textString = [[NSString alloc ] initWithFormat:@"您选择了：%@%@%@", firstString, @" 里的 ", subString]; self.textField.text = textString; } - (IBAction)selectButton:(id)sender { [textField endEditing:YES]; }大功告成，运行，点击TextField，弹出：

最终代码：http://download.csdn.net/detail/totogo2010/4393004

著作权声明：本文由http://blog.csdn.net/totogo2010/原创，欢迎转载分享。请尊重作者劳动，转载时保留该声明和作者博客链接，谢谢