点按即可更改UIImageView alpha状态

Question

希望通过点击手势更改UIimageview alpha,例如:

点击 - 将alpha更改为0.5f
再次点击 - alpha返回1状态

可能吗？

Answer 1

是.

将点击手势识别器附加到视图:

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(yourFunction:)];
[imageView addGestureRecognizer:tap];

然后在手势识别器的处理程序中:

if (imageView.alpha > 0.5f){
    imageView.alpha = 0.5f;
}
else {
    imageView.alpha = 1.0;
}