效果:
72F2FA61-5CE4-4D2F-BA1C-B30146F2956E.png
废话不多少,直接上代码:
#import "ViewController.h"
@interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>
{
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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