iOS:选择器控件UIPickerView的详解和演示

选择器控件UIPickerView:

功能：它能够创建一个类似于密码锁式的单列或多列的选择菜单，用户可以通过它设置的代理来选择需要菜单中的任意的数据。例如创建日历、字体表(类型、大小、颜色)、图库等.

它是UIView视图的子类，而且遵从UIPickerViewDelegate协议和UIPickerViewDataSource协议。因此，选择器需要设置代理去进行操作;
设置视图控制器self为数据源代理和数据操作代理,即
@property(strong,nonatomic)UIPickerView *pickerView;
self.pickerView.dataSource = self;
self.pickerView.delegate = self;

一、具体类信息：

@protocol UIPickerViewDataSource, UIPickerViewDelegate;

@interface UIPickerView : UIView <NSCoding>

@property(nonatomic,assign) id<UIPickerViewDataSource> dataSource; // default is nil,设置代理

@property(nonatomic,assign) id<UIPickerViewDelegate> delegate; // default is nil，设置代理

@property(nonatomic) BOOL showsSelectionIndicator; // default is NO

@property(nonatomic,readonly) NSInteger numberOfComponents; //列数

二、协议UIPickerViewDataSource

@protocol UIPickerViewDataSource<NSObject>

@required //必须要实现的方法

// 返回的列显示的数量。

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;

//返回行数在每个组件(每一列)

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;

@end

三、协议UIPickerViewDelegate

@protocol UIPickerViewDelegate<NSObject>

@optional //可以选择执行的方法

//每一列组件的列宽度

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component;

//每一列组件的行高度

- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component;

// 返回每一列组件的每一行的标题内容

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

// 返回每一列组件的每一行的标题内容的属性

- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component;

// 返回每一列组件的每一行的视图显示

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view;

//执行选择某列某行的操作

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

@end

演示一：制作简单的万年历,一开始就显示当前日期

#import "ViewController.h"
2
3 @interface ViewController ()
4 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
5 @property (strong,nonatomic)NSArray *imageNames;
6 @end
7
8 @implementation ViewController
9
10 - (void)viewDidLoad {
11     [super viewDidLoad];
12     //初始化数据
13     NSMutableArray *mutImageNames = [NSMutableArray arrayWithCapacity:9];
14     for(int i=0; i<9; i++)
15     {
16         [mutImageNames addObject:[NSString stringWithFormat:@"%d.png",i]];
17     }
18     self.imageNames = mutImageNames;
19
20     //设置pickerView的数据源和代理
21     self.pickerView.dataSource = self;
22     self.pickerView.delegate = self;
23
24 }
25 #pragma mark - pickerview代理方法
26 -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
27 {
28     return 1;
29 }
30 -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
31 {
32     return self.imageNames.count;
33 }
34 //设置行高
35 -(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
36 {
37     UIImage *image = [UIImage imageNamed:self.imageNames[0]];
38     return image.size.height;
39 }
40 //设置每行显示的视图
41 -(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
42 {
43     UIImage *image = [UIImage imageNamed:self.imageNames[row]];
44     //UIImageView *imageView = [[UIImageView alloc]initWithImage:image];
45     //imageView.frame = CGRectMake(0, 0, image.size.width, image.size.height);
46     //return imageView;
47
48     UIButton *button = [[UIButton alloc]initWithFrame:CGRectMake(0, 0,image.size.width, image.size.height)];
49     [button setBackgroundImage:image forState:UIControlStateNormal];
50     [button addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
51     return button;
52 }
53 -(void)buttonClicked:(UIButton *)sender
54 {
55     NSLog(@"button clicked");
56 }
57 @end

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