iOS开发之PickerView和DatePicker的简单使用
Picker View和Date Picker是iOS开发中很常用的两个空间，设置出生日期，选择国家城市省份以及性别啊等等，都会用都这两个控件。
一、Picker View：
@interface UIPickerView : UIView <NSCoding, UITableViewDataSource> @property(nullable,nonatomic,weak) id<UIPickerViewDataSource> dataSource; // default is nil. weak reference @property(nullable,nonatomic,weak) id<UIPickerViewDelegate> delegate; // default is nil. weak reference @property(nonatomic) BOOL showsSelectionIndicator; // default is NO // info that was fetched and cached from the data source and delegate @property(nonatomic,readonly) NSInteger numberOfComponents; - (NSInteger)numberOfRowsInComponent:(NSInteger)component; - (CGSize)rowSizeForComponent:(NSInteger)component; // returns the view provided by the delegate via pickerView:viewForRow:forComponent:reusingView: // or nil if the row/component is not visible or the delegate does not implement // pickerView:viewForRow:forComponent:reusingView: - (nullable UIView *)viewForRow:(NSInteger)row forComponent:(NSInteger)component; // Reloading whole view or single component - (void)reloadAllComponents; - (void)reloadComponent:(NSInteger)component; // selection. in this case, it means showing the appropriate row in the middle - (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated; // scrolls the specified row to center. - (NSInteger)selectedRowInComponent:(NSInteger)component; // returns selected row. -1 if nothing selected @end
可以看到，它有一个数据源和一个代理属性，分别遵守UIPickerViewDataSource和UIPickerViewDelegate协议。
@protocol UIPickerViewDataSource<NSObject> @required // returns the number of 'columns' to display. //返回一共有多少列 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView; // returns the # of rows in each component.. //返回第component列有多少行 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component; @end @protocol UIPickerViewDelegate<NSObject> @optional // returns width of column and height of row for each component. //返回第component列的宽度 - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component; //返回第component列的行高 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component; // these methods return either a plain NSString, a NSAttributedString, or a view (e.g UILabel) to display the row for the component. // for the view versions, we cache any hidden and thus unused views and pass them back for reuse. // If you return back a different object, the old one will be released. the view will be centered in the row rect //返回每一行的标题 - (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component; //返回每一行的富文本标题 - (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component NS_AVAILABLE_IOS(6_0); // attributed title is favored if both methods are implemented - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view; //主动选中第component列第row行时调用该方法，一定是手动选择时才会调用 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component; @end
//
// ViewController.m
//
// Created by Daniel on 16/3/21.
// Copyright © 2016年 Daniel. All rights reserved.
//
#import "ViewController.h"
@interface ViewController () <UIPickerViewDelegate, UIPickerViewDataSource>
@property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
@property (weak, nonatomic) IBOutlet UILabel *frultLable;
@property (weak, nonatomic) IBOutlet UILabel *mainLable;
@property (weak, nonatomic) IBOutlet UILabel *drinkLable;
@property (nonatomic, strong) NSArray *foods;
@end
@implementation ViewController
- (NSArray *)foods {
if (_foods == nil) {
NSString *path = [[NSBundle mainBundle]pathForResource:@"foods.plist" ofType:nil];
_foods = [NSArray arrayWithContentsOfFile:path];
}
return _foods;
}
/**
* 点击时随机给lable赋值
*
* @param sender
*/
- (IBAction)random:(id)sender {
for (int i = 0; i < 3; i++) {
NSInteger count = [self.foods[i] count];
int random = arc4random_uniform((u_int32_t)count);
//pickerView每一列随机显示一行
[self.pickerView selectRow:random inComponent:i animated:YES];
//将选中的值显示到lable上
[self pickerView:_pickerView didSelectRow:random inComponent:i];
}
}
- (void)viewDidLoad {
[super viewDidLoad];
//初始化lable
for (int i = 0; i < 3; i++) {
[self pickerView:_pickerView didSelectRow:0 inComponent:i];
}
}
#pragma mark - <UIPickerViewDataSource>
// returns the number of 'columns' to display.
/**
* 返回一共有多少列
*
* @param pickerView
*
* @return
*/
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return self.foods.count;
}
/**
* 返回第component列有多少行
*
* @param pickerView
* @param component
*
* @return
*/
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
return [self.foods[component] count];
}
#pragma mark - <UIPickerViewDelegate>
/**
* 返回每一行的高度
*
* @param pickerView
* @param component
*
* @return
*/
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component {
return 40;
}
/**
* 返回每一行的标题
*
* @param pickerView
* @param row
* @param component
*
* @return
*/
- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
return self.foods[component][row];
}
/**
* 主动选中第component列第row行时调用该方法
*
* @param pickerView
* @param row
* @param component
*/
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
switch (component) {
case 0:
_frultLable.text = self.foods[component][row];
break;
case 1:
_mainLable.text = self.foods[component][row];
break;
case 2:
_drinkLable.text = self.foods[component][row];;
break;
}
}
@end
二、Date Picker：