学步园

1. File -> New Project -> View-based Application ->  输入工程名称 PickerView

2. PickerViewViewController.h

    #import <UIKit/UIKit.h><br /> @interface PickerViewViewController : UIViewController<UIPickerViewDataSource, UIPickerViewDelegate><br /> {<br /> UIPickerView *m_pPickerView;<br /> NSArray *m_data;<br /> }<br /> @property (nonatomic, retain) IBOutlet UIPickerView *m_pPickerView;<br /> @property (nonatomic, retain) NSArray *m_data;<br /> @end 

3. PickerViewViewController.m

    #import "PickerViewViewController.h"<br /> @implementation PickerViewViewController<br /> @synthesize m_pPickerView, m_data;<br /> /*<br /> // The designated initializer. Override to perform setup that is required before the view is loaded.<br /> - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {<br /> self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];<br /> if (self) {<br /> // Custom initialization<br /> }<br /> return self;<br /> }<br /> */<br /> /*<br /> // Implement loadView to create a view hierarchy programmatically, without using a nib.<br /> - (void)loadView {<br /> }<br /> */</p> <p>// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.<br /> - (void)viewDidLoad {<br /> NSArray *arr = [[NSArray alloc] initWithObjects:@"白菜", @"包心菜", @"菠菜", @"韭菜", @"冬瓜", @"胡萝卜", @"竹笋", nil];</p> <p> self.m_data = arr;<br /> [arr release];</p> <p> [super viewDidLoad];<br /> }<br /> /*<br /> // Override to allow orientations other than the default portrait orientation.<br /> - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {<br /> // Return YES for supported orientations<br /> return (interfaceOrientation == UIInterfaceOrientationPortrait);<br /> }<br /> */<br /> - (void)didReceiveMemoryWarning {<br /> // Releases the view if it doesn't have a superview.<br /> [super didReceiveMemoryWarning];</p> <p> // Release any cached data, images, etc that aren't in use.<br /> }<br /> - (void)viewDidUnload {<br /> // Release any retained subviews of the main view.<br /> // e.g. self.myOutlet = nil;<br /> m_pPickerView = nil;<br /> m_data = nil;<br /> [super viewDidUnload];<br /> }</p> <p>- (void)dealloc {<br /> [m_pPickerView release];<br /> [m_data release];<br /> [super dealloc];<br /> }<br /> #pragma mark -<br /> #pragma mark Picker View Data Source Methods<br /> - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView<br /> {<br /> return 1;<br /> }<br /> - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component<br /> {<br /> return [m_data count];<br /> }<br /> #pragma mark -<br /> #pragma mark Picker View Delegate Methods<br /> - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component<br /> {<br /> return [m_data objectAtIndex:row];<br /> }<br /> @end 

4. 双击 PickerViewViewController.xib， 按下shift + command + L, 拖一个PickerView 放到View上。

    按下control 键同时从 File's Owner 拖动到 PickerView 控件上，连接输入口(IBOutlet).

    按下 command + 2, 把 dataSource和delegate 拖动到File's Owner上。

5. 运行后的效果如下: