Objective-c 动画块似乎没有触发

Question

我的 UIView 子类“Card”中有一个方法可以通过将其 alpha 从 1 淡化为 0 来关闭实例。当我将卡片添加到超级视图时，我会执行类似的操作，并且它会淡入淡出。但是当我调用 fadeAway 时，它会立即消失。演示代码在我的控制器类中。这是我的 Card.h 和 Card.m

---

#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>

@class Card;

@interface Card : UIView {

 int            upperOperand;
    int         lowerOperand;
    NSString*   theOperator;
    int         theResult;
}

@property(nonatomic) int upperOperand;
@property(nonatomic) int lowerOperand;
@property(nonatomic, retain) NSString* theOperator;
@property(nonatomic) int theResult;

- (void)fadeAway;

@end

---

#import "Card.h"

@implementation Card

@synthesize upperOperand;
@synthesize lowerOperand;
@synthesize theOperator;
@synthesize theResult;

- (void)fadeAway {
    self.alpha = 1.0f;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:2.0f];
    [UIView setAnimationCurve:UIViewAnimationCurveLinear];
    self.alpha = 0.0f;
    [UIView commitAnimations];  

    [self removeFromSuperview];
}

- (id)initWithFrame:(CGRect)frame {
    if ((self = [super initWithFrame:frame])) {
        // Initialization code
        self.backgroundColor = [UIColor redColor];
        self.layer.cornerRadius = 15;
        self.alpha = 1.0;
        self.layer.borderColor = [[UIColor blueColor] CGColor];
        self.layer.borderWidth = 4;
    }
    return self;

   - (void)dealloc {
    [super dealloc];
}

@end

---

Answer 1

由于您要立即从其超级视图中删除 self，我认为它没有机会执行动画。

您可能想查看setAnimationDidStopSelector:。这里有一个讨论：Animation End Callback for CALayer?

另一个想法是延迟删除子视图。例如，

[self performSelector:@selector(removeFromSuperview) 
    withObject:nil 
    afterDelay:2.0f];