UIPickerView 使用详解

效果:

72F2FA61-5CE4-4D2F-BA1C-B30146F2956E.png

废话不多少,直接上代码:

#import "ViewController.h"

@interface ViewController ()

{
    NSArray *_provinceArr;
    NSArray *allArr;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self loadData];
    [self loadPickerView];
}

/** 设置数据源 并初始化控件*/

/** 数据源 */
- (void)loadData {
    //省这个数组的位置位于第0列
    _provinceArr = [[NSArray alloc] initWithObjects:@"河北省",@"河南省",@"山东省", nil];
    
    //小数组对应的是省数组中的省份
    NSArray *heiBeiArr = [[NSArray alloc] initWithObjects:@"石家庄",@"唐山",@"秦皇岛",@"邯郸",@"保定",@"邢台", nil];
    NSArray *heNanArr = [[NSArray alloc] initWithObjects:@"郑州",@"新乡",@"安阳",@"驻马店", nil];
    NSArray *shangDongArr = [[NSArray alloc] initWithObjects:@"日照",@"济南",@"淄博",@"青岛",@"德州", nil];
    allArr = @[heiBeiArr,heNanArr,shangDongArr];
}
/** 初始化控件 */
- (void)loadPickerView {
    
    UIPickerView *pickView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 100, self.view.frame.size.width, 400)];
    pickView.delegate = self;
    pickView.dataSource = self;
    pickView.showsSelectionIndicator = YES;
    
    [self.view addSubview:pickView];
}

UIPickerView的协议方法

#pragma mark --- UIPickerViewDelegate
/** 设置组件中每行的标题row:行 */
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    if (component == 0) {
        return _provinceArr[row];
    }else{
        NSInteger selectedRow = [pickerView selectedRowInComponent:0];
        NSArray *arr = [allArr objectAtIndex:selectedRow];
        
        return [arr objectAtIndex:row];
    }
}
/** 当选择某一个列中的某一行的时候会调用该方法 */
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    //在拖动第 0 列行的时候, 要及时的刷新第 1 列的数据
    if (component == 0) {
        //如果滑动的是第 0 列, 刷新第 1 列
        //在执行完这句代码之后, 会重新计算第 1 列的行数, 重新加载第 1 列的标题内容
        [pickerView reloadComponent:1];//重新加载指定列的数据
        [pickerView selectRow:0 inComponent:1 animated:YES];
        //
        
        //重新加载数据
        //[pickerView reloadAllComponents];
    }
}

/** 设置组件的宽度 */
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
    if (component == 0) {
        return 100;
    }else{
        return 80;
    }
    
}
/** 设置组件中每行的高度 */
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
    if (component == 0) {
        return 60;
    }else{
        return 60;
    }
}

//- (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component {}
//- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view{}



- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

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