如何“可选”基于块的UIView动画？

animated

if (animated) {
    [UIView beginAnimations:@\"Foo\"];
    [UIView setAnimationDuration:5.0];
}
// ... layout views ...
if (animated) {
    [UIView commitAnimations];
}

[UIView animateWithDuration:(animated ? 5.0 : 0.0) animations:^{
    // ... layout views ...
}];

UIView animate...

void (^myViewChanges)(void) = ^() {
    myView.alpha = 0.5;
    // other changes you want to make to animatable properties
};

if (animated) {
    [UIView animateWithDuration:5.0f animations:myViewChanges];
} else {
    myViewChanges();
}