学步园

    前面iOS学习之UIPickerView控件的简单使用 用到的UIPickerView弹出来是通过
textField.inputView = selectPicker;   textField.inputAccessoryView = doneToolbar; 这中方法来做的。如果UIPickerView或UIDatePicker控件通过其他按钮或事件激活的时候怎么能像系统那样弹出来呢？为了实现这个需求，就要用到动画效果了。

1、新建一个Single View App项目,在.xib文件中添加控件如下：

2、创建xib和ViewController的连接

#import <UIKit/UIKit.h>  
  
@interface ViewController : UIViewController  
@property (retain, nonatomic) IBOutlet UIDatePicker *pickerView;  
- (IBAction)popView:(id)sender;  
- (IBAction)inView:(id)sender;  
@property  (nonatomic, retain) NSString *string;  
@end 

3、隐藏pickerView

- (void)viewDidLoad  
{  
    [super viewDidLoad];  
    self.pickerView.frame = CGRectMake(0, 480, 320, 260);  
}  

- (IBAction)popView:(id)sender {  
      
    CGContextRef context = UIGraphicsGetCurrentContext();  
    [UIView beginAnimations:nil context:context];  
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];  
    [UIView setAnimationDuration:0.6];//动画时间长度，单位秒，浮点数  
    [self.view exchangeSubviewAtIndex:0 withSubviewAtIndex:1];  
    self.pickerView.frame = CGRectMake(0, 245, 320, 260);  
      
    [UIView setAnimationDelegate:self];  
    // 动画完毕后调用animationFinished  
    [UIView setAnimationDidStopSelector:@selector(animationFinished)];  
    [UIView commitAnimations];  
}  
  
- (IBAction)inView:(id)sender {  
    CGContextRef context = UIGraphicsGetCurrentContext();  
    [UIView beginAnimations:nil context:context];  
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];  
    [UIView setAnimationDuration:0.6];//动画时间长度，单位秒，浮点数  
    self.pickerView.frame = CGRectMake(0, 480, 320, 260);  
      
    [UIView setAnimationDelegate:self];  
    // 动画完毕后调用animationFinished  
    [UIView setAnimationDidStopSelector:@selector(animationFinished)];  
    [UIView commitAnimations];  
}  
-(void)animationFinished{  
    NSLog(@"动画结束!");  
} 

  

4、代码块的方法做动画弹出pickerView

- (void)ViewAnimation:(UIView*)view willHidden:(BOOL)hidden {  
      
    [UIView animateWithDuration:0.3 animations:^{  
        if (hidden) {  
            view.frame = CGRectMake(0, 480, 320, 260);  
        } else {  
            [view setHidden:hidden];  
            view.frame = CGRectMake(0, 245, 320, 260);  
        }  
    } completion:^(BOOL finished) {  
        [view setHidden:hidden];  
    }];  
}  

5、在Action中调用

- (IBAction)popView:(id)sender {  
  
    [self ViewAnimation:self.pickerView willHidden:NO];  
}  
  
- (IBAction)inView:(id)sender {  
    [self ViewAnimation:self.pickerView willHidden:YES];  
  
}