IOS UI控件之Picker View
Picker View的使用,通常有一系列相同类型元素的控件都会有一些代理方法和数据源.像tableView 、CollectionView等。Picker也是一样的,以前学过了tableView，这次再次使用Picker的时候就轻松了很多。
首先，说一下最近看到的一点细微的知识点吧.这点肯定很多人都知道了。不过还是要记录一下的。最近在iphone中使用[UIScreen mainScreen].bounds看到了整个能操作屏幕大小为(375, 667),除去状态栏要占用的20，所以可用高度就是647了。开发的时候还是要注意的。
下面来关于PickerView怎么使用。我是刚开始学就是IOS 8开始的。也没接触过别的版本。所以就直接用storeboard 来开发界面了。当然使用代码也是可以的。两者都不是很难。首先在storeboard中拖一个Picker View。并且使用IBOutlet 来连接类中的控件属性。在viewController中声明要实现的代理。在.m文件中实现相关的数据源和代理。就能够完成Picker View的初始化了》
下面是.m文件的相关实现代码
<span style="font-family:Comic Sans MS;font-size:18px;">//
// SecondViewController.m
// PickerDemo
//
// Created by terry on 14/12/22.
// Copyright (c) 2014年 huawei. All rights reserved.
//
#import "NormalViewController.h"
@interface NormalViewController ()<UIPickerViewDelegate,UIPickerViewDataSource> {
NSMutableArray *_country;
}
@property (weak, nonatomic) IBOutlet UIPickerView *countryPicker;
@property (weak, nonatomic) IBOutlet UIPickerView *clubPicker;
@end
@implementation NormalViewController
- (void)viewDidLoad {
[super viewDidLoad];
_country = [NSMutableArray arrayWithObjects:@"中国", @"美国", @"日本", @"韩国", nil];
self.countryPicker.delegate = self;
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 1;
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
return [_country count];
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
return _country[row];
}
@end
</span>
这样就能够完成Picker View的简单使用了。确实很简单吧
后面完成两个Picker..这个差不多跟tableView中的section一样,只需要在
<span style="font-family:Comic Sans MS;font-size:18px;">- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 2;
}</span>
<span style="background-color: rgb(255, 255, 255);"><span style="font-family:Comic Sans MS;font-size:18px;">这个代理方法中返回2或者n即可.在另外的两个代理方法中分别通过compont来定义数据源。</span></span>
下面是实现的两个Picker同时使用的写法
<span style="font-family:Comic Sans MS;font-size:18px;">- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
//
// SecondViewController.m
// PickerDemo
//
// Created by terry on 14/12/22.
// Copyright (c) 2014年 huawei. All rights reserved.
//
#import "NormalViewController.h"
@interface NormalViewController ()<UIPickerViewDelegate,UIPickerViewDataSource> {
NSMutableArray *_country;
NSMutableArray *_clubArray;
}
@property (weak, nonatomic) IBOutlet UIPickerView *countryPicker;
@property (weak, nonatomic) IBOutlet UIPickerView *clubPicker;
@end
@implementation NormalViewController
- (void)viewDidLoad {
[super viewDidLoad];
_country = [NSMutableArray arrayWithObjects:@"中国", @"美国", @"日本", @"韩国", nil];
_clubArray = [NSMutableArray arrayWithObjects:@"LGD", @"IG", @"CK", @"DK", nil];
self.countryPicker.delegate = self;
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 2;
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
if (component == 0) {
return [_country count];
}else {
return [_clubArray count];
}
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
if (component == 0) {
return [_country objectAtIndex:row];
}else {
return [_clubArray objectAtIndex:row];
}
}
@end
}
</span>
后面就是相关联Picker的使用了。其实不用之前也应该能够想到，就是使用字典等数据结构把数据绑定在一起就可以了当第一个Picker中的数据显示时，判断选中的item，更新第二个或者第三个Picker即可.下面是我写的一个具体实现
//
// SecondViewController.m
// PickerDemo
//
// Created by terry on 14/12/22.
// Copyright (c) 2014年 huawei. All rights reserved.
//
#import "NormalViewController.h"
@interface NormalViewController ()<UIPickerViewDelegate,UIPickerViewDataSource> {
NSMutableArray *_country;
NSMutableArray *_clubArray;
NSMutableDictionary *_dict;
NSMutableArray *_data;
NSString *_countrySelect;
}
@property (weak, nonatomic) IBOutlet UIPickerView *countryPicker;
@property (weak, nonatomic) IBOutlet UIPickerView *clubPicker;
@end
@implementation NormalViewController
- (void)viewDidLoad {
[super viewDidLoad];
_country = [NSMutableArray arrayWithObjects:@"中国", @"美国", @"日本", @"韩国", nil];
_clubArray = [NSMutableArray arrayWithObjects:@"LGD", @"IG", @"CK", @"DK", nil];
_data = _country;
_dict = [NSMutableDictionary dictionary];
[_dict setObject:_country forKey:@"country"];
[_dict setObject:_clubArray forKey:@"club"];
self.countryPicker.delegate = self;
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 2;
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
if (component == 0) {
_data= [_dict objectForKey:[[_dict allKeys] objectAtIndex:row]];
[pickerView selectRow:0 inComponent:1 animated:YES];
[pickerView reloadComponent:1];
}
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
if (component == 0) {
return [_dict allKeys].count;
}else {
return _data.count;
}
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
if (component == 0) {
return [_dict allKeys][row];
}else {
return _data[row];
}
}
@end
这样就完成了Picker View的基本功能了。
后面有一个 DatePicker 一个具体的实例，通过datePicker.date来获取 选中的日期.具体的代码就不具体看了。这个就更加简单了。