009 在Xcode4.5上创建IOS6.0应用 (高级控件 拾取器)

IOS中的高级控件拾取器

在学习这个高级控件之前先建立好项目

然后按照在   《008 在Xcode4.5上创建IOS6.0应用 (多视图应用程序)》中的方法建立两个视图

最后在AppDelegate.m文件中添加如下代码（图中的红框内代码为新添加的代码） 注意要在AppDelegate.m文件中引入

第一种：时间拾取器 时间拾取器这个在实现起来最为简单 第一步在视图中添加控件

第二步：设置它的属性

第三步：编码实现其中的效果 FirstViewController.h

@interface FirstViewController : UIViewController{
    IBOutlet UIDatePicker *uidataPicker;
}

@property(nonatomic,retain)UIDatePicker *uidataPicker;

-(IBAction)onClick:(id)sender;

@end
           

FirstViewController.m

@synthesize uidataPicker;

-(IBAction)onClick:(id)sender{
    NSDate *selected = [uidataPicker date];
    NSString *message = [[NSString alloc] initWithFormat:@"您选择的日期是: %@",selected];
    
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"选择的日期"
                                                    message:message delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil, nil];
    
    [alert show];
    [alert release];
    
    [message release];
}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"First", @"First");
        self.tabBarItem.image = [UIImage imageNamed:@"first"];
    }
    return self;
}
							
- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)dealloc
{
    [uidataPicker release];
    [super dealloc];
}

@end
           

第四步：为其控件连线

这样下来，一个简单的时间拾取器这样就完成了

第二种：单个标签拾取器（比较复杂）

第一步：加入控件-->实现输入输出--> 最后注意要输出数据一定要注意图中第3步

第二步：编码 需要注意的是要在SecondViewController.h文件中实现两个协议

< UIPickerViewDataSource,UIPickerViewDelegate>

源码如下：

@interface SecondViewController : UIViewController< UIPickerViewDataSource,UIPickerViewDelegate>{
    IBOutlet UIPickerView *pickView;
    NSArray * arr;
}

@property (nonatomic,retain)UIPickerView *pickView;
@property (nonatomic,retain)NSArray * arr;

-(IBAction)onClick:(id)sender;
@end
           

然后在SecondViewController.m文件中编码

实现协议后必须实现协议里面的三个方法分别为

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component｛｝

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView｛｝

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component｛｝

然后必须在初始化的时候创建一个定义了拾取器中内容的数组

也就拾在ViewDidLoad方法中

NSArray *array = [[NSArrayalloc]initWithObjects:@"欧洲",@"南美洲", @"非洲",@"北美洲",@"亚洲",@"大洋洲",nil];

源代码如下：

@implementation SecondViewController

@synthesize pickView;
@synthesize arr;

-(IBAction)onClick:(id)sender{
    NSInteger row = [pickView selectedRowInComponent:0];
    NSString *selected = [arr objectAtIndex:row];
    NSString *title = [[NSString alloc] initWithFormat:@"您选择了 %@!",selected];
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"选择的日期"
                                                    message:title
                                                   delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil, nil];
    
    [alert show];
    [alert release];
    [title release];
    [selected release];
}

//pragma mark 实现协议UIPickerViewDelegate方法
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    return [arr objectAtIndex:row];
}

//pragma mark 实现协议UIPickerViewDataSource方法
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 1;
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    return [arr count];
}


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"Second", @"Second");
        self.tabBarItem.image = [UIImage imageNamed:@"second"];
    }
    return self;
}
							
- (void)viewDidLoad
{
    [super viewDidLoad];
	NSArray *array = [[NSArray alloc] initWithObjects:@"欧洲",@"南美洲",
                      @"非洲",@"北美洲",@"亚洲",@"大洋洲",nil];
    self.arr = array;
    [array release];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)dealloc
{
    [pickView release];
    [arr release];
    [super dealloc];
}

@end
           

最后再次提醒一定要加入上图第三步中的连线

最后再看看效果图

第三种：双标签拾取器（如果上面那个搞清楚了这个就相对比较简单）

由于这个只是把拾取器从1个变成了2个所以在定义集合变量的时候要定义两个

ThreeViewController.h

@interface ThreeViewController : UIViewController< UIPickerViewDataSource,UIPickerViewDelegate>{
    IBOutlet UIPickerView *pickView;
    NSArray * arr1;
    NSArray * arr2;
}

@property (nonatomic,retain)UIPickerView *pickView;
@property (nonatomic,retain)NSArray * arr1;
@property (nonatomic,retain)NSArray * arr2;

-(IBAction)onClick:(id)sender;

@end
           

ThreeViewController.m文件也只要做点点的修改就行了，说白了，就拾一个变两个的过程

@implementation ThreeViewController

@synthesize pickView;
@synthesize arr1;
@synthesize arr2;

-(IBAction)onClick:(id)sender{
    NSInteger row1 = [pickView selectedRowInComponent:0];
    NSInteger row2 = [pickView selectedRowInComponent:1];
    NSString *selected1 = [arr1 objectAtIndex:row1];
    NSString *selected2 = [arr2 objectAtIndex:row2];
    
    NSString *title = [[NSString alloc] initWithFormat:@"您选择了%@中的%@!",selected1,selected2];
    
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"选择"
                                                    message:title
                                                   delegate:nil
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil, nil];
    
    [alert show];
    [alert release];
    [title release];
    [selected1 release];
    [selected2 release];
}

//pragma mark 实现协议UIPickerViewDelegate方法
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    if (component == 0) {
        return [arr1 objectAtIndex:row];
    }else if(component == 1){
        return [arr2 objectAtIndex:row];
    }else{
        return nil;
    }
}

//pragma mark 实现协议UIPickerViewDataSource方法
-(NSInteger) numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 2;
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    if (component ==0) {
        return [arr1 count];
    }else if (component == 1){
        return [arr2 count];
    }else{
        return 0;
    }
}




- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"Three", @"Three");
        self.tabBarItem.image = [UIImage imageNamed:@"first"];
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSArray *array1 = [[NSArray alloc] initWithObjects:@"欧洲",@"南美洲",
                      @"非洲",@"北美洲",@"亚洲",@"大洋洲",nil];
    NSArray *array2 = [[NSArray alloc] initWithObjects:@"足球",@"篮球",
                       @"羽毛球",@"乒乓球",@"保龄球",@"铅球",nil];
    self.arr1 = array1;
    self.arr2 = array2;
    [array1 release];
    [array2 release];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)dealloc
{
    [pickView release];
    [arr1 release];
    [arr2 release];
    
    [super dealloc];
}

@end
           

第四种：双标签拾取器有联动效果（如果上面那个搞清楚了这个就相对比较简单）

有联动效果的拾取器相对与第三种稍微麻烦一点

首先来看看源代码

FourViewController.h

@interface FourViewController : UIViewController< UIPickerViewDataSource,UIPickerViewDelegate>{
    NSDictionary *date;
    IBOutlet UIPickerView *pickView;
    NSArray * arr1;
    NSArray * arr2;
}

@property(nonatomic,retain)NSDictionary *date;

@property (nonatomic,retain)UIPickerView *pickView;
@property (nonatomic,retain)NSArray * arr1;
@property (nonatomic,retain)NSArray * arr2;

-(IBAction)onClick:(id)sender;
@end
           

FourViewController.m

@implementation FourViewController


@synthesize date;
@synthesize pickView;
@synthesize arr1;
@synthesize arr2;


//pragma mark 实现协议UIPickerViewDelegate方法
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    if (component == 0) {
        return [arr1 objectAtIndex:row];
    }else if(component == 1){
        return [arr2 objectAtIndex:row];
    }else{
        return nil;
    }
}

//pragma mark 实现协议UIPickerViewDataSource方法
-(NSInteger) numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 2;
}


-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    if (component ==0) {
        return [arr1 count];
    }else if (component == 1){
        return [arr2 count];
    }else{
        return 0;
    }
}


//实现联动的效果
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
    if(component ==0){
        NSString *selectedCol1 = [self.arr1 objectAtIndex:row];
        NSArray *array = [self.date objectForKey:selectedCol1];
        self.arr2 = array;
        [self.pickView reloadComponent:1];
    }
}


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"Four", @"Four");
        self.tabBarItem.image = [UIImage imageNamed:@"second"];

    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSBundle * bundle = [NSBundle mainBundle];
    NSString * plistPath = [bundle pathForResource:@"statedictionary"
                                            ofType:@"plist"];
    
    NSDictionary * dict = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
    self.date = dict;
    
    [dict release];
    
    NSArray *col1 = [self.date allKeys];
    //下面这个方法是排序的意思
    NSArray *sorted = [col1 sortedArrayUsingSelector:@selector(compare:)];
    self.arr1 = sorted;
    
    NSArray *seleteCol1 = [self.arr1 objectAtIndex:0];
    NSArray *col2 = [self.date objectForKey:seleteCol1];
    self.arr2 = col2;
    
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)dealloc
{
    [date release];
    [pickView release];
    [arr1 release];
    [arr2 release];
    [super dealloc];
}
@end
           

代码中与上一个有小区别的是

多了一个联动是调用的方法

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

还多了一个变量这个变量是字典变量

唯一不同的是这次获取内容是从文件中获取的

下面就来介绍一下定义文件的过程

第一步：看图建立文件

第二步：编辑文件中的内容（由于Xcode为我们提供了比较好的编辑工具所以文件编辑过程就不多做介绍）

但是要注意下图红框中的内容一但填错就得不到数据

在选择Root类型的时候一定要选择字典类型

最后看两张效果图片

最后拾取器就这样介绍完了，看了以上的介绍一定觉得拾取器还是比较简单的控键把。