iPhone开发【六】常用控件之Picker View-白红宇的个人博客

iPhone开发【六】常用控件之Picker View

发布日期：2021-09-28 18:46:11 浏览次数：12 分类：技术文章

本文共 6368 字，大约阅读时间需要 21 分钟。

转载请注明出处，原文网址：作者：张燕广

实现的功能：演示Picker View的使用方法

关键词：Picker View

1、创建一个Single View Application工程，命名为：PickersDemo，如下图

2、修改ViewController.xib，添加一个Picker View和一个Button控件，如下

连接输出口、操作，如下

3、视图控制器ViewController，需要实现协议UIPickerViewDataSource、UIPickerViewDelegate中的必须实现的方法，

在工程目录依次展开Frameworks->UIKit.framework->Headers，然后打开UIPickerView.h，在文件的尾部可以看到协议UIPickerViewDataSource、UIPickerViewDelegate的定义，如下

4、修改ViewController.h：

[cpp]
 //  
 //  ViewController.h  
 //  PickersDemo  
 //  
 //  Created by Zhang Yanguang on 12-10-25.  
 //  Copyright (c) 2012年 MyCompanyName. All rights reserved.  
 //  
   
 #import <UIKit/UIKit.h>  
 #define kDeviceCategory 0  
 #define kDeviceName 1  
   
 @interface ViewController : UIViewController  
   
 @property(strong,nonatomic)IBOutlet UIPickerView *picker;  
 @property(nonatomic,retain)NSDictionary *appleDevices;  
 @property(nonatomic,retain)NSArray *deviceCategory;  
 @property(nonatomic,retain)NSArray *deviceName;  
   
 -(IBAction)buttonPressed:(id)sender;  
 @end  

5、修改ViewController.m：

[cpp]
 //  
 //  ViewController.m  
 //  PickersDemo  
 //  
 //  Created by Zhang Yanguang on 12-10-25.  
 //  Copyright (c) 2012年 MyCompanyName. All rights reserved.  
 //  
   
 #import "ViewController.h"  
   
 @interface ViewController ()  
   
 @end  
   
 @implementation ViewController  
 @synthesize picker;  
 @synthesize appleDevices;  
 @synthesize deviceCategory;  
 @synthesize deviceName;  
   
 - (void)viewDidLoad  
 {  
     [super viewDidLoad];  
     // Do any additional setup after loading the view, typically from a nib.  
     NSArray *array1 = [NSArray arrayWithObjects:@"iPhone",@"iPad",@"iPod",nil];  
     NSArray *array2 = [NSArray arrayWithObjects:@"Mac",@"iMac",@"Mac Mini",@"Mac Pro",nil];  
     NSDictionary  *dictionary= [NSDictionary dictionaryWithObjectsAndKeys:array1,@"Mobile",array2,@"Computers",nil];//注意用nil结束  
     appleDevices = [[NSDictionary alloc]initWithDictionary:dictionary copyItems:YES];  
       
     NSArray *components = [self.appleDevices allKeys];  
     NSArray *sorted = [components sortedArrayUsingSelector:@selector(compare:)];  
     self.deviceCategory = sorted;  
       
     NSString *selectedCategory = [self.deviceCategory objectAtIndex:0];  
     self.deviceName = [self.appleDevices objectForKey:selectedCategory];  
 }  
   
 - (void)viewDidUnload  
 {  
     [super viewDidUnload];  
     picker = nil;  
     appleDevices = nil;  
     deviceCategory = nil;  
     deviceName = nil;  
     // Release any retained subviews of the main view.  
 }  
   
 -(void)dealloc{  
     [picker release];  
     [appleDevices release];  
     [deviceCategory release];  
     [deviceName release];  
 }  
   
 -(IBAction)buttonPressed:(id)sender{  
     NSString *selectedCategory = [self.deviceCategory objectAtIndex:[self.picker selectedRowInComponent:kDeviceCategory]];  
     NSString *selectedDevice = [self.deviceName objectAtIndex:[self.picker selectedRowInComponent:kDeviceName]];  
     //NSLog(@"%@-%@",selectedCategory,selectedDevice);  
   
     UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"结果" message:[NSString stringWithFormat:@"%@:%@",selectedCategory,selectedDevice]  delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];  
     [alertView show];  
 }  
   
 - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation  
 {  
     return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);  
 }  
   
 #pragma mark Picker View  DataSource methods  
 // returns the number of 'columns' to display.  
 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{  
     return 2;  
 }  
   
 // returns the # of rows in each component..  
 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{  
     if(component == kDeviceCategory){  
         return [self.deviceCategory count];  
     }else{  
         return [self.deviceName count];  
     }  
 }  
   
 #pragma mark Picker View  Delegate methods  
 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{  
     if(component == kDeviceCategory){  
         return [self.deviceCategory objectAtIndex:row];  
     }else{  
         return [self.deviceName objectAtIndex:row];  
     }  
 }  
   
 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{  
     if(component == kDeviceCategory){  
         NSString *selectedCategory = [self.deviceCategory objectAtIndex:row];  
         NSArray *array = [self.appleDevices objectForKey:selectedCategory];  
         self.deviceName = array;  
           
         [self.picker selectRow:0 inComponent:kDeviceName animated:YES];  
         [self.picker reloadComponent:kDeviceName];  
     }  
 }  
   
 @end  

6、编译、运行，效果如下：

=========================================================================

以下是我实现的，更为简单的单选择器：

////  MyTestViewController.m//  MyTest////  Created by H3c on 13-1-4.//  Copyright (c) 2013年.H3c All rights reserved.//#import "MyTestViewController.h"@interface MyTestViewController ()@end@implementation MyTestViewController@synthesize picker;@synthesize appleDevices;@synthesize deviceCategory;@synthesize deviceName;- (void)viewDidLoad{    [super viewDidLoad];    NSArray *arr1 = [NSArray arrayWithObjects:@"1",@"5",@"7",@"4", nil] ;        // 排序    NSArray *sorted = [arr1 sortedArrayUsingSelector:@selector(compare:)];    self.deviceCategory = sorted;        // 设定默认值    [self.picker selectRow:2 inComponent:0 animated:YES];}- (void)viewDidUnload{    picker = nil;    appleDevices = nil;    deviceCategory = nil;    deviceName = nil;    [super viewDidUnload];}-(void)dealloc{    [picker release];    [appleDevices release];    [deviceCategory release];    [deviceName release];    [super dealloc];}- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];}- (IBAction)click:(id)sender{    // 获取选中内容    NSString *selectedCategory = [self.deviceCategory objectAtIndex:[self.picker selectedRowInComponent:0]];        UIAlertView *alertV = [[UIAlertView alloc]initWithTitle:@"Note" message:selectedCategory delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:nil, nil];    [alertV show];}// 列数-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{    return 1;}// 行数-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{    return [self.deviceCategory count];}// Cell内容-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{    return [self.deviceCategory objectAtIndex:row];}@end

#import 
   
    #define one  0;@interface MyTestViewController : UIViewController
    
     @property(strong,nonatomic)IBOutlet UIPickerView *picker;@property(nonatomic,retain)NSDictionary *appleDevices;@property(nonatomic,retain)NSArray *deviceCategory;@property(nonatomic,retain)NSArray *deviceName;- (IBAction)click:(id)sender;@end

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