今天博主有一个UIPickerView的需求,遇到了一些困难点,在此和大家分享,希望能够共同进步.
UIPickerView是一个选择器控件，它比UIDatePicker更加通用，它可以生成单列的选择器，也可生成多列的选择器，而且开发者完全可以自定义选择项的外观，因此用法非常灵活.
UIPickerView直接继承了UIView，没有继承UIControl，因此，它不能像UIControl那样绑定事件处理方法，UIPickerView的事件处理由其委托对象完成.
self.viewOfPick=[[UIPickerView alloc]initWithFrame:CGRectMake(100, 0, 200, [UIScreen mainScreen].bounds.size.height)];
_viewOfPick.dataSource=self;
_viewOfPick.delegate=self;
//pickerView默认选中row为0,无线滚动只是在一开始的时候显示row的中间值,造成无线滚动的假象
[_viewOfPick selectRow:9 inComponent:0 animated:YES];
//设置pickerView默认选中最后一行
[_viewOfPick selectRow:9 inComponent:1 animated:YES];
[self.view addSubview:_viewOfPick];
//类似tableView的cell for row,根据row和component返回字符串显示
- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component __TVOS_PROHIBITED
{
return @"空";
}
//类似tableView的didSelect,根据row和component进行具体的传值等操作
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component __TVOS_PROHIBITED
{
NSLog(@"*********%ld,%ld",(long)component,row);
}
//类似tableView的cell for row,根据row和component返回自定义视图显示
//注意,同时实现返回NSString 和下面这个 返回UIView的方法,只执行返回UIView的方法
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view __TVOS_PROHIBITED
{
UIView *blackView=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 10, 10)];
blackView.backgroundColor=[UIColor blackColor];
return blackView;
}
//返回pickerView的行高
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component __TVOS_PROHIBITED
{
return 40;
}
// returns the number of ‘columns‘ to display.component的数量
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}
// returns the # of rows in each component..row的数量
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return 10;
}