CATransaction begin example in Objective C (iOS).

CATransaction begin

Begin a new transaction for the current thread.

+ (void)begin

Discussion of [CATransaction begin]
The transaction is nested within the thread’s current transaction, if there is one.

CATransaction begin example.

[CATransaction begin];
[topLayer addAnimation:topAnimation forKey:@"flip"];
[bottomLayer addAnimation:bottomAnimation forKey:@"flip"];
[CATransaction commit];

Example of [CATransaction begin].

.h

+ (void)transactionWithDuration:(NSTimeInterval)duration
                     animations:(void (^)(void))animations;
.m

+ (void)transactionWithDuration:(NSTimeInterval)duration
                     animations:(void (^)(void))animations;
{
    [CATransaction begin];
    [CATransaction setValue:[NSNumber numberWithFloat:duration] forKey:kCATransactionAnimationDuration];
    animations();
    [CATransaction commit];
}
Usage with your code (assuming you made it a category on UIView)

[UIView transactionWithDuration:3 animations:^{

    CGPoint low  = CGPointMake(0.150, 0.000);
    CGPoint high = CGPointMake(0.500, 0.000);

    CAMediaTimingFunction* perfectIn =
        [CAMediaTimingFunction functionWithControlPoints:low.x
                                                        :low.y
                                                        :1.0 - high.x
                                                        :1.0 - high.y];
    [CATransaction setAnimationTimingFunction: perfectIn];
    CABasicAnimation *fadeIn = [CABasicAnimation animationWithKeyPath:@"opacity"];
    fadeIn.fromValue = [NSNumber numberWithFloat:0];
    fadeIn.toValue = [NSNumber numberWithFloat:1.0];
    [viewB.layer addAnimation:fadeIn forKey:@"animateOpacity"];

}];

CATransaction begin example.

[CATransaction begin];
[CATransaction setAnimationDuration:0.5];
[CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[CATransaction setCompletionBlock:^{
    NSLog(@"blabla");
}];

// Create the CABasicAnimation using your existing code
CABasicAnimation *myPropertyAnim = [CABasicAnimation animationWithKeyPath:@"myProperty"];
// TODO: Setup animation range
myPropertyAnim.toValue = newValue;

// The CATransaction does not observe arbitrary properties so this fails:
//myLayer.myProperty = newValue;

// Add the CAAnimation subclass during the CATransaction
[myLayer addAnimation:myPropertyAnim forKey:@"myKey"];

[CATransaction commit];

End of CATransaction begin example article.