iphone褪色的图像

Question

wat我想要的是在图像视图中显示图像并在5秒后淡化图像并显示下一个图像.图像存储在数组对象中...我能够在5秒后成功转换图像.我想要的是在5秒后淡出第一个图像并显示下一个图像必须在无限循环中发生...下面是代码,它对图像之间的正常过渡非常有用..我想要的是图像的淡化...并在下面的代码中添加淡入过渡

- (void)viewDidLoad {

    imgView.animationImages=[NSArray arrayWithObjects:  
                             [UIImage imageNamed:@"lori.png"],
                             [UIImage imageNamed:@"miranda.png"],
                             [UIImage imageNamed:@"taylor.png"],
                             [UIImage imageNamed:@"ingrid.png"],
                             [UIImage imageNamed:@"kasey.png"], 
                             [UIImage imageNamed:@"wreckers.png"], nil];


    imgView.animationDuration=20.0;
    imgView.animationRepeatCount=0;
    [imgView startAnimating];
    [self.view addSubview:imgView];
    [imgView release];



    [super viewDidLoad];
}

Answer 1

您可以使用重复的NSTimer来调用一种特殊的方法,该方法可以连续地将图像视图alpha属性设置为0.0到1.0.以下是我编写的一些代码:

- (void)viewDidLoad {
    imgView.animationImages=[NSArray arrayWithObjects:  
                             [UIImage imageNamed:@"lori.png"],
                             [UIImage imageNamed:@"miranda.png"],
                             [UIImage imageNamed:@"taylor.png"],
                             [UIImage imageNamed:@"ingrid.png"],
                             [UIImage imageNamed:@"kasey.png"], 
                             [UIImage imageNamed:@"wreckers.png"], nil];



    imgView.animationDuration=20.0;
    imgView.animationRepeatCount=0;
    [imgView startAnimating];
    [self.view addSubview:imgView];
    [imgView release];
    //The timers time interval is the imageViews animation duration devided by the number of images in the animationImages array. 20/5 = 4 
    NSTimer *timer = [NSTimer timerWithTimeInterval:4.0 
                                              target:self 
                                            selector:@selector(onTimer) 
                                            userInfo:nil 
                                             repeats:YES];

    [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
    [timer fire];

    [super viewDidLoad];
}

//It is important that the animation durations within these animation blocks add up to 4 
//(the time interval of the timer). If you change the time interval then the time intervals 
//in these blocks must also be changed to refelect the amount of time an image is displayed. 
//Failing to do this will mean your fading animation will go out of phase with the switching of images.   

-(void)onTimer{
        [UIView animateWithDuration:3.0 animations:^{
            imgView.alpha = 0.0; 
        }];
        [UIView animateWithDuration:1.0 animations:^{
            imgView.alpha = 1.0; 
        }];
    }

如果希望淡入淡出持续时间持续5秒而不是4秒,则需要将图像视图animationDuration属性增加到25,然后增加两个块中的淡入淡出动画持续时间,使得淡入淡出时间= 5.