UIPickerView控件在给用户选择某些特定的数据时经常使用到，这里演示一个简单的选择数据，显示在UITextField输入框里，把UIPickerView作为输入View，用Toolbar作为选定数据的按钮。和其他UITableView控件相似，UIPickerView也需要数据源。
我们要实现的效果如下：
下面开始使用的步骤。
1、打开XCode 4.3.2，新建一个Single View Application ,命名为PickerViewDemo，Company Identifier 为：com.rongfzh.yc
2、拖放控件
2.1、拖放一个UIPickerView，放置在View的最下方
2.2、拖放一个Toolbar控件，放置在View的外面，让它不属于View的子控件，并把item命名为“完成”，效果如下：
2.3 放置一个Flexible Space Bar Button Item 撑开
2.4 放一个UITextField,用来显示选择的数据
3、创建映射
在ViewController.xib文件里按 alt + command+ enter键，打开Assistant Editor，按住Control键，选择各个控件，拖拽到 ViewController.h文件里，生成以下变量代码
#import <UIKit/UIKit.h>
@interface ViewController : UIViewController
{
NSArray *pickerArray;
}
- (IBAction)selectButton:(id)sender;
@property (strong, nonatomic) IBOutlet UIToolbar *doneToolbar;
@property (strong, nonatomic) IBOutlet UIPickerView *selectPicker;
@property (strong, nonatomic) IBOutlet UITextField *textField;
@end
4、实现数据源和协议
ViewController.h文件里实现
<UIPickerViewDelegate, UITextFieldDelegate,UIPickerViewDataSource>
#import <UIKit/UIKit.h>
@interface ViewController : UIViewController<UIPickerViewDelegate, UITextFieldDelegate,UIPickerViewDataSource>
{
NSArray *pickerArray;
}
- (IBAction)selectButton:(id)sender;
@property (strong, nonatomic) IBOutlet UIToolbar *doneToolbar;
@property (strong, nonatomic) IBOutlet UIPickerView *selectPicker;
@property (strong, nonatomic) IBOutlet UITextField *textField;
@end
ViewController.m文件
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;
}
-(NSInteger) pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
return [pickerArray count];
}
-(NSString*) pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
return [pickerArray objectAtIndex:row];
}
-(void)textFieldDidEndEditing:(UITextField *)textField{
NSInteger row = [selectPicker selectedRowInComponent:0];
self.textField.text = [pickerArray objectAtIndex:row];
}
上面numberOfComponentsInPickerView返回有几个PickerView ，
textFieldDidEndEditing这个在textField结束编辑时，显示PickerView选择中的数据。
Toolbar 的item的完成按钮
- (IBAction)selectButton:(id)sender {
[textField endEditing:YES];
}
5、初始化
- (void)viewDidLoad
{
[super viewDidLoad];
pickerArray = [NSArray arrayWithObjects:@"动物",@"植物",@"石头",@"天空", nil];
textField.inputView = selectPicker;
textField.inputAccessoryView = doneToolbar;
textField.delegate = self;
selectPicker.delegate = self;
selectPicker.dataSource = self;
selectPicker.frame = CGRectMake(0, 480, 320, 216);
}
代码解释：
设置委托
textField.delegate =self;
selectPicker.delegate =self;
selectPicker.dataSource =self;
隐藏UIPickerView
selectPicker.frame =CGRectMake(0,480,320, 216);
运行：
UIPickerView控件的关联选择
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：
