iOS开发UIPickerView常用属性方法
Posted
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了iOS开发UIPickerView常用属性方法相关的知识，希望对你有一定的参考价值。
//
// ViewController.m
// UIPickerViewAll
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
/*
UIPickView控件常用的方法和属性：
(1) - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView; 返回PickerView的列数
(2) - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;
返回PickView的component列对应的行数
(3) - (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;
返回每一列每一行的内容
(4) - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component;
用户选中PickView的某一列和某一行时会调用该方法
(5) - (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component
修改PickView中component列row行的文本的样式
(6) - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view 该方法返回的UIView的控件将直接作为UIPickView对应的component 列row行的列表项
(7) - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component 设置component列对应的行高
(8) - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
该方法设置component列对应的宽度
(9) - (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated
该方法设置选中的UIPickView 第component列row行项，最后一个参数animated代表是否要用到动画
(10) @property(nonatomic,readonly) NSInteger numberOfComponents;
获取UIPickerView指定列中包含的列表项的数量，该属性是只读的
*/
//简单实用
//- (void)viewDidLoad
//{
// [super viewDidLoad];
//
// //获取需要展示的数据
// [self loadData];
//
// // 初始化pickerView
// self.pickerView = [[UIPickerView alloc]initWithFrame:CGRectMake(0, 50, self.view.bounds.size.width, 200)];
// [self.view addSubview:self.pickerView];
//
// //指定数据源和委托
// self.pickerView.delegate = self;
// self.pickerView.dataSource = self;
//}
//#pragma mark 加载数据
//-(void)loadData
//{
// //需要展示的数据以数组的形式保存
// self.letter = @[@"aaa",@"bbb",@"ccc",@"ddd"];
// self.number = @[@"111",@"222",@"333",@"444"];
//}
//
//#pragma mark UIPickerView DataSource Method 数据源方法
//
////指定pickerview有几个表盘
//-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
//{
// return 2;//第一个展示字母、第二个展示数字
//}
//
////指定每个表盘上有几行数据
//-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
//{
// NSInteger result = 0;
// switch (component) {
// case 0:
// result = self.letter.count;//根据数组的元素个数返回几行数据
// break;
// case 1:
// result = self.number.count;
// break;
//
// default:
// break;
// }
//
// return result;
//}
//
//#pragma mark UIPickerView Delegate Method 代理方法
//
////指定每行如何展示数据（此处和tableview类似）
//-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
//{
// NSString * title = nil;
// switch (component) {
// case 0:
// title = self.letter[row];
// break;
// case 1:
// title = self.number[row];
// break;
// default:
// break;
// }
//
// return title;
//}
#pragma mark 两个联动
- (void)viewDidLoad
{
[super viewDidLoad];
//加载数据
[self loadData];
//指定委托
self.pickerView.delegate = self;
self.pickerView.dataSource = self;
}
//加载数据
-(void)loadData
{
NSString * path = [[NSBundle mainBundle]pathForResource:@"area" ofType:@"plist"];
self.provinces = [NSArray arrayWithContentsOfFile:path];
self.cities = [NSArray arrayWithArray:self.provinces[0][@"Cities"]];
//label的布局约束
self.label = [[UILabel alloc]initWithFrame:CGRectZero];
self.label.translatesAutoresizingMaskIntoConstraints = NO;
self.label.backgroundColor = [UIColor groupTableViewBackgroundColor];
self.label.textColor = [UIColor greenColor];
self.label.font = [UIFont systemFontOfSize:30];
[self.label setTextAlignment:NSTextAlignmentCenter];
[self.view addSubview:self.label];
NSArray * labelTop = [NSLayoutConstraint constraintsWithVisualFormat:@"V:[_pickerView]-30-[_label(50)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_pickerView,_label)];
NSArray * labelH = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-20-[_label]-20-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_label)];
[self.view addConstraints:labelTop];
[self.view addConstraints:labelH];
}
//有几个表盘（component）
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}
//没个表盘有几行数据（rows）
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
NSInteger rows = 0;
switch (component) {
case 0:
rows = self.provinces.count;//根据plist文件中的数据返回rows
break;
case 1:
rows = self.cities.count;
break;
default:
break;
}
return rows;
}
//每行的标题
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
NSString * title = nil;
switch (component) {
case 0:
title = self.provinces[row][@"State"];
break;
case 1:
title = self.cities[row][@"city"];
break;
default:
break;
}
return title;
}
//选中时回调的委托方法，在此方法中实现省份和城市间的联动
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
switch (component) {
case 0://选中省份表盘时，根据row的值改变城市数组，刷新城市数组，实现联动
self.cities = self.provinces[row][@"Cities"];
[self.pickerView reloadComponent:1];
break;
case 1:
self.label.text = [NSString stringWithFormat:@"%@%@",self.provinces[[self.pickerView selectedRowInComponent:0]][@"State"],self.cities[[self.pickerView selectedRowInComponent:1]][@"city"]];//如果选中第二个
break;
default:
break;
}
}
//修改pickerview的title样式
//#pragma mark pickerView Method
//- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
//{
// return 1;//表盘数量
//}
//
////判断是哪个pickerview，返回相应的rows
//- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
//{
// NSInteger rows = 0;
//
// if (pickerView == self.pickerView)
// {
// rows = self.pickerViewArr.count;
// }
// else
// {
// rows = self.pickerViewArr2.count;
// }
//
// return rows;
//}
//
////判断是哪个pickerview，返回相应的title
//- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
//{
// NSString *str = nil;
//
// if (pickerView == self.pickerView)
// {
// str = self.pickerViewArr[row];
// }
// else
// {
// str = self.pickerViewArr2[row];
// }
// return str;
//}
//
//#pragma mark 给pickerview设置字体大小和颜色等
//- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
//{
// //可以通过自定义label达到自定义pickerview展示数据的方式
// UILabel* pickerLabel = (UILabel*)view;
//
// if (!pickerLabel)
// {
// pickerLabel = [[UILabel alloc] init];
// pickerLabel.adjustsFontSizeToFitWidth = YES;
// pickerLabel.textAlignment = NSTextAlignmentCenter;
// [pickerLabel setBackgroundColor:[UIColor lightGrayColor]];
// [pickerLabel setFont:[UIFont boldSystemFontOfSize:15]];
// }
//
// pickerLabel.text=[self pickerView:pickerView titleForRow:row forComponent:component];//调用上一个委托方法，获得要展示的title
// return pickerLabel;
//}
////选中某行后回调的方法，获得选中结果
//- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
//{
// if (pickerView == self.pickerView)
// {
// self.pickerViewSelect = self.pickerViewArr[row];
// NSLog(@"selected == %@",self.pickerViewSelect);
// }
// else
// {
// self.pickerViewSelect2 = self.pickerViewArr2[row];
// }
//}
//转自链接：http://www.jianshu.com/p/811882ba8d78
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
以上是关于iOS开发UIPickerView常用属性方法的主要内容，如果未能解决你的问题，请参考以下文章