UIViewAnimation with block

UIViewAnimationWithBlocks使用block,动画结束后不需要使用回调方法，相比UIViewAnimation 方式要简洁很多

- (void)setSelectedVeg:(id)sender

{    

    [selectedVegetableIcon setAlpha:0.0];

    [UIView animateWithDuration:0.4

                     animations: ^{

                         float angle = [self spinnerAngleForVegetable:sender];

                         [vegetableSpinner setTransform:CGAffineTransformMakeRotation(angle)];

                     } 

                     completion:^(BOOL finished) {

                         [selectedVegetableIcon setAlpha:1.0];

                     }];

}

以上代码来自WWDC2010 iPlant PlantCareViem.m

UIViewAnimation style Animation

- (void)setSelectedVeg:(id)sender

{    

    [selectedVegetableIcon setAlpha:0.0];

[UIView beginAnimations:@"setSelectedVeg" context:nil];

float angle = [self spinnerAngleForVegetable:sender];

[vegetableSpinner setTransform:CGAffineTransformMakeRotation(angle)];

[UIView setAnimationDuration:0.4];

[UIView setAnimationDelegate:self];

[UIView setAnimationDidStopSelector:@selector(done)];

[UIView commitAnimations];

}

-(void)done

{

[selectedVegetableIcon setAlpha:1.0];

}