1,代理
//UIPickView和TableView一样,想要展示数据也要设置数据源和代理
// 设置数据源
self.pickView.dataSource = self;
// 设置代理
self.pickView.delegate = self;
//遵守数据源,代理协议:
@interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>
@property (weak, nonatomic) IBOutlet UIPickerView *pickView;
@end
//实现数据源代理方法:
//总共有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 3;
}
//第component列有多少行.
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
return 4;
}
//返回每一列的宽度
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component{
}
//返回第一列的高度
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{
return 50;
}
//返回每一行的标题
- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
return @"gaowei";
}
//返回每一行的视图UIView
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view{
UIButton *btn = [UIButton buttonWithType:UIButtonTypeContactAdd];
return btn;
}
2,简单Demo
image.png
#import "ViewController.h"
@interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>
//展示数据的pickView
@property (weak, nonatomic) IBOutlet UIPickerView *pickView;
//数组当中有3个小数组, 每一个小数组代表一列.每一列小数组的个数代表这一列有多少行.
@property(nonatomic,strong) NSArray *foodArray;
//显示当前选中的食物
@property (weak, nonatomic) IBOutlet UILabel *foodLabel;
@end
@implementation ViewController
//懒加载数据
-(NSArray *)foodArray{
if (_foodArray == nil) {
// 获取Plist文件的路径
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil];
// 从Plist文件当中加载数组.
_foodArray = [NSArray arrayWithContentsOfFile:filePath];
}
return _foodArray;
}
- (void)viewDidLoad {
[super viewDidLoad];
// 设置数据源
self.pickView.dataSource = self;
// 设置代理
self.pickView.delegate = self;
}
//总共有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
// 数组当中有几个元素, 就展示多少列.每一个元素代表一列,
return self.foodArray.count;
}
//第component列有多少行.
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
// 取出当前所在的列.每一列都是一个数组.
NSArray *array = self.foodArray[component];
//返回每一组当中, 每一个小数组的数个, 也就是这一组里面有多少行.
return array.count;
}
//返回每一行的标题
- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
// 取出当前所在的列.每一列都是一个数组.
NSArray *componentArray = self.foodArray[component];
// 返回小数组当中每一个元素
return componentArray[row];
}
//点击了哪一列的哪一行
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
NSString *food = self.foodArray[component][row];
self.foodLabel.text = food;
}
