ios - 图像动画

Question

我有一个 scrollview 和 imageview subview to scrollview.on a button click I subview another imageview 并通过

将该图像发送到该现有图像的背面

[nextImageView sendSubviewToBack:firstImageView];

我希望 firstImageView 在单击按钮时淡入淡出并显示第二个图像，在单击按钮时我也希望发生相反的情况

Answer 1

好的，据我了解，您希望通过单击按钮“切换”输入和输出几个图像。尝试以下操作，其中“img1”是第一个 UIImageView，“img2”是第二个 UIImageView。这称为 animation block .

-(IBAction)showSecondImg:(id)sender {

     // Some code to add Img2 subview behind Img1..

     [UIImageView animateWithDuration:1 // <--  Number of seconds 
                     animations:^{
                     img1.alpha = 0; // <-- fade out in 1 second and shows Img2 below it
                     //add other animations here, like background color, etc. if needed.
                     }
     ];
}

-(IBAction)showFirstImg:(id)sender {

          // gradually fades the first UIImageView back on top
         [UIImageView animateWithDuration:1 
                         animations:^{
                         img1.alpha = 1;
                         }
         ];
    }