iOS學習之UIPickerView控制項的關聯選擇

接上篇iOS學習之UIPickerView控制項的簡單使用 

接著上篇的代碼 http://download.csdn.net/detail/totogo2010/4391870 ，我們要實現的效果如下：

當選擇左邊的一級選項時，左邊展示一級選項裡含有的二級選項，選擇後顯示在TextField裡。

如何?呢？建立一個和左邊的列表key對應的數組，當選擇這個key時，重新整理左邊UIPickerView部分的內容顯示對應數組的資料，選擇時，找到

兩個UIPickerView組件rowIndex，找出資料，放到TextField裡。

1、開啟上篇PickerViewDemo項目，在ViewController.h添加兩個成員變數：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:@"動物",@"植物",@"石頭", nil];    dicPicker = [NSDictionary dictionaryWithObjectsAndKeys:                 [NSArray arrayWithObjects:@"魚",@"鳥",@"蟲子",            nil], @"動物",                 [NSArray arrayWithObjects:@"花",@"草",@"葵花",            nil], @"植物",                 [NSArray arrayWithObjects:@"瘋狂的石頭",@"花崗岩",@"鵝卵石", nil], @"石頭",nil];        subPickerArray = [dicPicker objectForKey:@"動物"];    textField.inputView = selectPicker;    textField.inputAccessoryView = doneToolbar;    textField.delegate = self;    selectPicker.delegate = self;    selectPicker.dataSource = self;    selectPicker.frame = CGRectMake(0, 480, 320, 216);}

給 NSDictionary *dicPicker;賦值，對應的三個關鍵字添加了對應的數組。

3、Component返回兩個，這樣就有兩個齒輪了。

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

4、使用宏

在#import "ViewController.h"下面定義兩個宏，代表UIPickerView齒輪的左邊的部分和右邊的部分。左邊的部分是0，右邊的是1.

#import "ViewController.h"

#define kFirstComponent 0

#define kSubComponent 1

5、判斷是那個齒輪，返回相應的資料的Count。

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

6、根據component返回相應的String資料

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

7、拖動左邊的齒輪時，右邊的資料相應的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、相應選擇的資料，並顯示在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:@"您選擇了：%@%@%@", firstString, @" 裡的 ", subString];    self.textField.text = textString;}- (IBAction)selectButton:(id)sender {    [textField endEditing:YES];}

大功告成，運行，點擊TextField，彈出：

最終代碼：http://download.csdn.net/detail/totogo2010/4393004

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