iOS开发UI篇—UIPickerView控件简单介绍

iOS开发UI篇—UIPickerView控件简单介绍

一.UIPickerView 控件

1.简单介绍：

 2.示例代码

TXViewController.m文件

//  Created by 鑫 on 14-10-15.

//  Copyright (c) 2014年 梁镋鑫. All rights reserved.

//

#import "TXViewController.h"

@interface TXViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>

@property (weak, nonatomic) IBOutlet UIPickerView *pickerView;

- (IBAction)randomFood;

@property(nonatomic ,strong)NSArray *foods;

@property (weak, nonatomic) IBOutlet UILabel *fruitLabel;

@property (weak, nonatomic) IBOutlet UILabel *mainLabel;

@property (weak, nonatomic) IBOutlet UILabel *drinkLabel;

@end

@implementation TXViewController

- (void)viewDidLoad

{

    [super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

    //初始化

//    self.fruitLabel.text = self.foods[0][0];

//    self.mainLabel.text = self.foods[1][0];

//    self.drinkLabel.text = self.foods[2][0];

    //手动调用代理方法  所以可用for循环，上面不可以

//    [self pickerView:nil didSelectRow:0 inComponent:0];

//    [self pickerView:nil didSelectRow:0 inComponent:1];

//    [self pickerView:nil didSelectRow:0 inComponent:2];

    for ( int Component  = 0; Component < self.foods.count; Component++) {

        [self pickerView:nil didSelectRow:0 inComponent:Component];

    }

}

//随机选中某一食物

- (IBAction)randomFood {

    //生成随机数

    //arc4random()%14; 生成0到14的随机数  ,[self.foods[0] count]取出第0列这个数组，这个数组在调用count这个方法

//    [self.pickerView selectRow:arc4random()%[self.foods[0] count] inComponent:0 animated:YES];

//    [self.pickerView selectRow:arc4random()%[self.foods[1] count] inComponent:1 animated:YES];

//    [self.pickerView selectRow:arc4random()%[self.foods[2] count] inComponent:2animated:YES];

    //  用for循环

    for (int component = 0; component < self.foods.count; component++) {

        //第component列数组的总长度

        int count = [self.foods[component]count];

        //之前的行号

        int oldrow = [self.pickerView selectedRowInComponent:component];

        //第几行 默认新的行号跟旧的行号一样

        int row =oldrow;

    //    arc4random()%count等价 arc4random_uniform(count);

        //保证行数不一样

        //之前的行号

        while (row ==oldrow) {

            row = arc4random()%count;

        }

        //让pickerView主动选中第component列第row行

        [self.pickerView selectRow:row inComponent:component animated:YES];

        //设置label的文字

        [self pickerView:nil didSelectRow:row inComponent:component];

    }

}

-(NSArray *)foods

{

    if (_foods == nil) {

        _foods = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle]pathForResource:@"foods" ofType:@"plist"]];

    }

    return _foods;

}

#pragma mark ---数据源方法

//一共多少列

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

{

    return self.foods.count;

}

//列。(NSInteger)component   第(NSInteger)componentl列显示多少行

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

{

   // 先取出第component列的数组

    NSArray *subfoods = self.foods[component];

    return subfoods.count;

}

#pragma mark  - - 代理方法

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

{

    //先取出第component列，在取出这个数组这一行

    return self.foods[component][row];

}

//选中第component列第row行

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

{

    NSLog(@"选中了第%d列第%d行",component, row);

    if (component ==0) {

        self.fruitLabel.text = self.foods[component][row];

    }

    else if(component ==1)

    {

        self.mainLabel.text = self.foods[component][row];

    }

    else if (component  == 2)

    {

        self.drinkLabel.text = self.foods[component][row];

    }

}

@end

实现效果：

二.UIPickerView 用法

1.UIPickerView的常见属性
// 数据源(用来告诉UIPickerView有多少列多少行)
@property(nonatomic,assign) id<UIPickerViewDataSource> dataSource;
// 代理(用来告诉UIPickerView每1列的每1行显示什么内容,监听UIPickerView的选择)
@property(nonatomic,assign) id<UIPickerViewDelegate>   delegate;
// 是否要显示选中的指示器
@property(nonatomic)        BOOL                       showsSelectionIndicator;
// 一共有多少列
@property(nonatomic,readonly) NSInteger numberOfComponents;

2.UIPickerView的常见方法
// 重新刷新所有列
- (void)reloadAllComponents;
// 重新刷新第component列
- (void)reloadComponent:(NSInteger)component;

// 主动选中第component列的第row行
- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated;

// 获得第component列的当前选中的行号
- (NSInteger)selectedRowInComponent:(NSInteger)component;

3.数据源方法(UIPickerViewDataSource)
//  一共有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;
//  第component列一共有多少行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;

4.代理方法(UIPickerViewDelegate)
//  第component列的宽度是多少
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component;
//  第component列的行高是多少
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component;

//  第component列第row行显示什么文字
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;

//  第component列第row行显示怎样的view(内容)
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view;

//  选中了pickerView的第component列第row行
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component;