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IOS 取值控件(UIPicker)的使用方法
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1.简单地取值控件示例
我们要做的一个UITextFiled,当点击UITextFiled，出现一个UIPick取值的页面，可以选择性别,在viewDidLoad中写下
//sexPicker
UIPickerView *sexPicker=[[UIPickerView alloc]init];
sexPicker.showsSelectionIndicator=YES;
sexPicker.delegate=self;
sexPicker.dataSource=self;
self.sex.inputView=sexPicker;
对于数据源回调函数和代理回调函数的实现，代码如下:
#pragma sexPicker
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return rSexComponentCount;
} -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return rSexRowCount;
} -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if(==row)
{
return @"Male";
}
else
{
return @"Female";
}
} -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
if (==row) {
self.sex.text=@"Male";
}
else
{
self.sex.text=@"FeMale";
}
}
显示结果如图：
2.UIPickData的使用
在viewDidLoad中添加如下代码：
//birthday Picker Choose
self.birthdate.clearButtonMode=UITextFieldViewModeNever;
UIDatePicker *birthPicker=[[UIDatePicker alloc]init];
birthPicker.datePickerMode=UIDatePickerModeDate;
//birthPicker.locale=[[NSLocale alloc]initWithLocaleIdentifier:<#(NSString *)#>];
NSDateFormatter *formatter=[[NSDateFormatter alloc]init];
formatter.dateFormat=@"MM-dd-yyyy";
NSString *stdDate=@"01-01-1990";
birthPicker.date=[formatter dateFromString:stdDate];
[birthPicker addTarget:self action:@selector(chooseDate:) forControlEvents:UIControlEventValueChanged];
self.birthdate.inputView=birthPicker;
其的触发事件函数
#pragma DatePicker
-(void)chooseDate:(UIDatePicker *)datePicker
{
NSDate *date=datePicker.date;
NSDateFormatter *formatter=[[NSDateFormatter alloc]init];
formatter.dateFormat=@"MM-dd-yyyy";
NSString *dateString=[formatter stringFromDate:date];
self.birthdate.text=dateString; //[showAllBarButton appendString:[[NSString alloc] initWithString:dateString]];
//self.barButtonItem.title=showAllBarButton; }
运行结果:
3.自定义UIPicker的选项外观
除了通过简单的字符串进行UIPicker的显示之外，系统也提供了自定义视图的方法来为每一个选项进行自定义，API如下：
-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
虽然在每次调用此方法时都重新生成一个全新的UIView子类对象，配置完后返回给调用者也能够达到自定义选项的效果。不过就像UITableView的重用机制般，这里也必须考虑到当选项数量特别巨大时，有理由使用此代理方法提供的reusingView参数来重用之前的视图。
所以为了方便维护和扩展起见，专门新建一个自定义的UIView子类比较好，取名为customRowView，考虑到需要让此类有一定的外部配置功能，所以customRowView的头文件可以设置如下:
#import <UIKit/UIKit.h> #define CUSTOM_HEIGHT 60.0f
#define CUSTOM_WIDTH 240.0f @interface HBCustomRowView : UIView
{
@private
UIImageView *_photoView;
UILabel *_nameLabel;
} @property(nonatomic,retain) UIImage *photo;
@property(nonatomic,retain) NSString *name; @end
上述代码中，两个属性photo和name是专供外部进行重用配置的，而长度的宏定义是为新建对象和实现特定UIPicker代理方法服务。
- (void)drawRect:(CGRect)rect
{
// Drawing code
//照片
if (!_photoView) {
_photoView = [[UIImageView alloc]initWithFrame:CGRectMake(10.0f, 0.0f, CGRectGetWidth(self.frame)-50.0f, CGRectGetHeight(self.frame))]; _photoView.backgroundColor = [UIColor clearColor];
[self addSubview:_photoView];
} _photoView.image=self.photo; //球员名字
if (!_nameLabel) {
_nameLabel = [[UILabel alloc] initWithFrame:CGRectMake(CGRectGetMaxX(_photoView.frame), 0.0f, CGRectGetWidth(self.frame)-CGRectGetMaxX(_photoView.frame)-5.0f, CGRectGetHeight(self.frame))];
_nameLabel.backgroundColor = [UIColor clearColor];
_nameLabel.textAlignment = NSTextAlignmentRight;
_nameLabel.textColor = [UIColor darkGrayColor];
_nameLabel.shadowColor = [UIColor blackColor];
_nameLabel.shadowOffset = CGSizeMake(1.0f, 1.0f);
_nameLabel.numberOfLines=;
_nameLabel.font = [UIFont systemFontOfSize:14.0f]; [self addSubview:_nameLabel];
}
_nameLabel.text=self.name;
}
然后需要UIPickerView准备一个数据源对象和代理对象，此对象的相关代码实现如下:
#pragma mark-
#pragma mark UIPicker datasource
//几列
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
//只显示球员
return ;
} //每列多少行选项
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return _datasource.count;
} #pragma mark-
#pragma mark UIPicker delegate
//每列的宽度
-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
{
return 240.0f;
} //每列的高
-(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
return 60.0f;
} //那列第几行的内容的标题
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
return @"";
} //选中任何列的某一行
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
} //自定义UIPickerView的选项视图
-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
HBCustomRowView *aCustomView = nil;
HBPlayerInfo *onePlayer =nil; //异常
if(row>=_datasource.count)
{
return [[UIView alloc]init];
}
//取出相应的球员对象
NSDictionary *player=[_datasource objectAtIndex:row];
onePlayer.name=[player objectForKey:@"name"];
onePlayer.role=[player objectForKey:@"role"];
onePlayer.number=[player objectForKey:@"number"];
if(view)
{
//重用
aCustomView=(HBCustomRowView *)view; //让重用的视图再次调用drawRect方法
[aCustomView setNeedsDisplay];
}
else
{
//新建
aCustomView =[[HBCustomRowView alloc]initWithFrame:CGRectMake(0.0f, 0.0f, 240.0f, 60.0f)];
aCustomView.backgroundColor=[UIColor clearColor];
} //配置自定义视图
aCustomView.photo = [UIImage imageNamed:@"gaolin.jpeg"];
aCustomView.name=onePlayer.name; return aCustomView;
}
